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Welcome!
This FAQ is a collection of aviation safety articles which I feel are of particular interest to sailplane pilots. A wide range of topics are covered. Any additions or corrections would be appreciated.
This article is Copyright (c) 1994, 1995, 1996 by Michael Steckner. It may be freely distributed in its entirety provided that this copyright notice is not removed. It may not be sold for profit nor incorporated in commercial documents without the author's written permission. This article is provided "as is" without express or implied warranty.
I would like to thank the following people who took the time to send me their comments. Many of them contributed substantial material for this FAQ. Some contributed unknowingly, as I lifted their posts directly from the newsgroup, obtained them from summaries kept by other people, or lifted them out of mailing lists.
Guy Ford Byars, Gosta Arvastson, Noel Matthews, Judah Milgram, Ronnie Moore, Ian Oldaker, Ake Pettersson, John Roake.
Special thanks to the Aviation Safety Institute, publishers of Monitor, for allowing me to reproduce several of their safety articles.
Special thanks to the Flight Training & Safety Committee of SAC (Soaring Association of Canada) and the Chairman, Ian Oldaker, for making the Safety Audit program document available.
I would like to thank John Leibacher for his assistance in producing the html formatted version of this FAQ.
Editor: Michael Steckner Mail address: 418 Eagle Trace Mayfield Heights,
OH 44124 USA Internet:
LIGHT POLARIZATION AND SUNGLASSES FOR
PILOTS
From the internet
NEW
FLYING AND DRUGS
New Zealand Gliding Kiwi (Original from Free Flight #3/1993 - Dr Peter
Perry)
Perhaps the key ingredient to an adequate scan is an expectation of danger. The best trained scanners are almost always ex-military pilots who have flown in war zones and lived with an anticipation of hostile aircraft attacks. They know only too well how important it is to see others in time to deal with them successfully. Civilian pilots are more likely to grow up with the "Big Friendly Sky" attitude which says, in effect: "There's tons and tons of airspace out there. How unlikely it is that two little airplanes are going to occupy the some blob of space at the same time!"
What we see is largely what we expect to see.
The human eye is a marvellous instrument, but it is not built like a radar, or even exactly like a camera. Our eyes can observe about a 200 degree arc of the horizon at one glance, but not everything we see will be sharp. In contrast to the camera, which can present all objects that lie within a 10 to 15 degree arc. That is because only a small area at the back of the eye, the fovea, is capable of sending sharp images to the brain. Any image that is not processed directly through the fovea will be blurred.
For example, an airplane that we can see distinctly with the foveal centre at seven miles would have to be as close as 7/10 of a mile in order to be recognized, if the angle of sight caused the image to reach the eye just out- side of the fovea. Hence the first rule of scanning is to examine relatively small blocks of airspace successively -- not all at once.
Another important fact is that it takes some time, as much as several minutes, for our eyes to adjust to the light level outside after a period of studying the instrument panel -- just as, conversely, it takes several minutes for us to adapt to a dimly lit room after having been in full daylight. For that reason bobbing your head in and out of the cockpit does not make for effective scanning. Since we are usually familiar with the instrument panel and we know what is there and what to look for, it is possible with some practice to keep the keep panel gauges and instruments within peripheral view while scanning through the windshield. In any event an exclusive panel scan, important as it is, may be accomplished in a much shorter time than an external scan.
Most experienced (and attentive) pilots can sense changes in the aircraft operation -- such as loss or gain of airspeed, pitch angle changes, etc. -- by means of feeling or sound. This minimizes the number of gauges or instruments that have to be monitored routinely. Ideally a pilot should spend only about one minute looking inside the cockpit for every three or four minutes he is looking outside.
Window panes or windshields obscured with dirt or bug stains make it difficult to scan the adjacent airspace, because our eyes tend naturally to focus on what is close at hand.
Forcing yourself to ignore the windshield distractions and scan beyond them puts a strain on your eyes which may weaken their effectiveness at distance. Cleaning the windows may seem like a rather menial job for a pilot, but if it has not been done before you get into the cockpit and you take off as is, you are burdening your vision unnecessarily.
A different sort of problem occurs when your field of vision contains no distinctive objects, such as during a flight above a cloud layer, or in haze. With nothing of apparent interest to see, your eyes tend to relax and come to rest at a comfortable focal distance of about 15 to 20 feet. This kind of near- sightedness, Or "empty field myopia," as it is formally called, is a dangerous substitute for active scanning. It also probably explains the frequent statement of crewmen following a near midair collision ". . . the plane suddenly materialized out of a clear blue sky." Chances are that the airplane was visible in the distance long before the observer's eyes focused upon it.
To scan apparently empty airspace effectively you have to direct your eyes to move in a slow deliberate pattern. Some pilots like to start at the upper left hand corner of a selected area or block of space and scan left to right, then down, right to left, and back up to the starting point. Then on to the ad- joining block with the same pattern, until the scan is complete. In time, as you learn to control your eye movements, you will see more and more objects that you missed earlier. It is something like looking for a dropped contact lens on a rug: if you examine the rug, imaginary square by square, you stand a much better chance of finding your lost lens than if you just stare at the entire floor covering. Incidently this system also works well for looking over "checkerboard" or mottled terrain that tends to camouflage aircraft.
There is no special scanning technique that works magic; you simply find one that you are comfortable with. Because we are in the habit of absorbing so much information from left to right this kind of motion seems to produce good eye-to-brain teamwork.
After each complete sweep, spend a few seconds looking over the instruments or charts, then resume scanning. Think of it not as a chore to be carried out periodically but as a continuous, ongoing flight activity that you can perform while talking on the radio, making conversation, maneuvering the airplane, drinking coffee, etc. Eventually you may become so accustomed to it that you will feel ill at ease when you are not scanning.
Then you will have the makings of a safe pilot.
WHAT YOU SEE IS NOT ALWAYS WHAT YOU GET (c)
[Reprinted with the kind permission of the Aviation Safety Institute]
This article is taken from the U.S. Naval Safety Center's publication called APPROACH -- February 1983, pp. 12-14. The article was written by Dr. R.A. Alkov of the Naval Safety Center (with the cooperation of Dr. Stanley Roscoe, New Mexico State University).
Although you will see liberal reference to Navy activities and some Navy terminology we felt that this article should be made available to you. Our special thanks to Admiral T.C. Steele, Commander of NSC, for granting us permission to reprint APPROACH articles.
[Edited for Safety FAQ]
Research conducted by Dr. Stanley Roscoe of New Mexico State University and others, notably Dr. Robert Randle of the NASA-Ames Research Center and Dr. Herschel Leibowitz and his students at Penn State, has provided some answers to these questions. To understand the mechanisms involved, let's quickly review the physiology of visual accommodation--the focusing of the eye.
The lens of the eye is elastic and changes its curvature to focus at different distances under the control of the ciliary muscle. This is known as the accommodation of the lens. It was once believed that relaxation of the ciliary muscle caused the eye to focus at optical infinity. We now know it focuses at a relatively short distance when at rest, although this resting distance varies greatly from person to person and moves outward as we get older. The typical result for pilots in flight is space myopia (or nearsightedness) while flying under conditions where there's little or no texture to focus on outside of the aircraft's surfaces. Relatively "empty" visual fields occur when you're flying at night, at high altitudes, over water or snow, or during a hazy day. Also, clouds have surprisingly little effect as stimuli for distant focusing. Under such conditions, the eye relaxes and allows the lens to seek an intermediate curvature that requires no particular focusing effort. This relaxed state is known as the dark focus.
The eyes are constantly involved in a tug-of-war between focusing on some stimulus and returning to the dark focus, with the stimulus normally pulling just hard enough to be seen and recognized. Most of the time in flight, however, there's no stimulus out there to pull the eyes' focus away from the dark focus.
As previously stated, the dark focus varies considerably with the individual, even among those with normal vision. To find your own dark focus, try an experiment first described by Dr. J. Mandelbaum in 1960 (in a ground-breaking article for the "American Medical Association Archives of Ophthalmology") and since called the Mandelbaum effect. From the screened-in porch of his summer cottage, he found he couldn't read a sign on the beach when he stood a certain distance from the screen. All he could focus on was the mesh of the screen. When he moved closer or farther away or moved his head from side to side, he could again read the sign. The distance from his eye to the screen when he couldn't read the sign turned out to be his dark focus, a fact later confirmed experimentally by Dr. Fred Owens at Penn State.
Even if you do have "normal" vision, your dark focus can vary with the time of day, your emotional state, your work- load, and your fatigue and stress levels. Furthermore, it has long been apparent that many naval aviators have much better than 20/20 vision, and there is a wide range of individual differences in perceptual abilities among those considered normal.
Empty-field myopia is reinforced by window posts and frames, some of which are quite close to the eyes. Traffic appearing along a line of sight close to a window post may by virtually invisible to the aviator. There are two main reasons for this. First, the nearby structure can serve as a focus trap. Probably even more important is the normal scan habit of looking to one side of a post with both eyes and then to the other with both eyes.
The two fixations are typically about 30 degrees apart. As a consequence, traffic appearing near one edge of the post will be as much as 15 degrees off the line of sight. Only if targets move, flash, or glisten will they be picked up soon enough in peripheral vision. Even targets that present an extended distinctive shape, such as a long, thin contrail, can be missed when they appear close to a window post. Remember, an aircraft on a collision course stays on the same relative bearing and doesn't appear to move--it only seems to grow. . .
Research reported by Dr. Stanley Roscoe has revealed a high correlation between the size an object is judged to be and the distance at which the eyes are focused. When the eye is focused close-up, we judge the apparent size of a more distant object to be smaller than it really is, and the converse is true when the eye is focused farther away. Since the apparent size of an object serves as a cue to distance, it follows that the perception of depth and distance depends upon where the eyes are focused.
The apparent size of an object is therefore influenced by other objects near the line of sight that also affect focus. Dr. Roscoe believes that this accounts for the popular illusion that the moon seems larger and closer when it is near the horizon than it does when viewed overhead in an empty sky. He's shown experimentally that changes in the apparent size of the moon (or other objects) correlate almost perfectly with the distance at which the eye is focused. When we look at the moon above a horizon, our eyes focus at a great distance; when we look up at the moon in the sky overhead, our eyes relax to a near point close to the dark focus, and the moon appears to shrink accordingly.
If you want to see for yourself, try sticking your thumb out at arm's length and closing one eye. Look at a relatively distant object with your thumb held near the line of view of the open eye and then alternately open and close your other eye while still looking at your thumb and the object. Notice the apparent change in size of the object, shrinking when one eye is closed and expanding when it's opened. The reason for this is that the closed eye tends to return to its dark focus and to pull the open eye with it. The compromise between the two eyes is about halfway between the dark focus and the distance of the object being viewed.
What about the guy landing short at night? When flying over water toward a lighted runway on a dark night, pilots with distant dark focuses, looking at the lights of a runway on the shore with the lights of a city beyond, suffer from the illusion that the runway is larger and therefore closer than it really is, and the runway threshold consequently appears lower in the visual field. An aviator in this situation may take off power too soon and land short (see "The Last Run of Flight 915," APPROACH, April 1974). Dr. Roscoe recommends that lead-in light buoys be used where this problem exists.
As to the overshooting accident, researchers an NASA- Ames have shown that intense stimulation of the inner ears, such as that caused by a sudden increase in cabin pressurization, results in an overaccommodation of the eyes' focusing mechanism. This causes the runway to appear smaller and farther away than it really is (see "The Fallacy of Pilot Error," AVIATION ACCIDENT INVESTIGATOR, December 1982). Outward accommodation is at least partially controlled by the sympathetic branch of the autonomic nervous system That's the one that allows us to run faster and fight harder when we're "psyched up." It increases our visual acuity by magnifying what we see to allow us to detect enemies or sight elusive prey when our adrenaline is pumping This mechanism has helped us since the days of the caveman. Can it be that today this same process causes the attack pilot's visual world to expand, making the ground appear lower and causing him to pull up too late?
It has been demonstrated that some people can be trained more easily than others to control the focal distance of their eyes. This ability is related to a person's dark focus and should be given consideration in the selection and training of aviators. A distant dark focus could be one basis for assigning a flier to fighter or attack aircraft. Individuals with a distant resting focus are not troubled as much by empty- field or space myopia.
Of course, as pilots gain more experience, they learn to compensate for biased distance judgments. As an individual ages, resting focus moves farther away so that target detection tends to improve. In extreme cases, however, a pilot who has "eagle eyes" may have serious problems in making a "black hole" approach at night and may be more likily to land in the water.
The key is detection. Now that we know that certain circumstances can alter our vision, we can take steps to voluntarily control our eyes' accommodation. There you have it; what you see is not always what you get, but you can learn ways to see more than you've ever seen before!
1. Benel, R.A. and Amerson, T.L., Jr., "The Dark Focus of Accommodation and Pilot Performance," In R.S. Jensen (ed.), First Symposium on Aviation Psychology, Columbus, OH, Aviation Psychology Laboratory, The Ohio State University, 1981, 182-191.
2. Clark, B., Randle, R.J., and Stewart, J.D., "Vestibular Ocular Accommodation Reflex in Man," Aviation Space and Environmental Medicine, 1975, 46, 1336-1339.
3. Leibowitz, H.W. and Owens, D.A., Anomalous myopias and the intermediate dark focus of accommodation, Science, 1975, 189,646-648.
4. Leibowitz, H.W., Hennessy, R.T., and Owens, K.A., "The Intermediate Resting Position of Accommodation and Some Implications for Space Perception, Psychologia, 1975, 18,162-170.
5. Owens, D.A., "The Mandelbaum Effect: Evidence for an Accommodative Bias Toward Intermediate Viewing Distances," Journal of the Optical Society of America, 1979, 69, 646-652.
6. Roscoe, S.N., Aviation Psychology, Ames, IA, The Iowa State University Press, 1980, 97-107.
7. Roscoe, S.N., "Landing Airplanes, Detecting Traffic, and the Dark Focus," Aviation, Space, and Environmental Medicine, 1982, 53, 970-976.
COLOUR SCHEMES FOR AIRCRAFT
Australian Gliding June 1990
As all pilots realize, safety in the air depends to a great extent on the ability to see and be seen. To this end, the colour of an aircraft can play an important role. The more easily you can see other aircraft and be seen yourself, the less chance there is of a mid-air collision.
In several parts of the world, experiments have been carried out to develop colours that are highly visible in all the usual flying conditions.
From these experiments have come some interesting results. It has been found that the most visible colours for an aircraft are yellow, orange and silver- grey.
One of the most interesting findings of these experiments was that all the colours outside the blue and orange red range gave a satisfactory visibility result. An aircraft painted sky blue, one would expect, would be invisible against a blue sky. This is not so, the experiments showed.
The real value of colour to an aircraft, it was found, is obtained by the correct use of colour contrast. Already some use has been made of this knowledge in the painting of registration letters. A combination of deep blue letter with a yellow orange border was proved to be visible at distances up to 12 km.
In Australia, several decades ago, we went through a stage of using Dayglo paint on rudders, wingtips and other parts of our sailplanes. The result might have been effective, but it was not particularly attractive to the appearance of the aircraft. Perhaps this was why it was eventually dropped.
One result of experiments in Australia is the realization that an aid to visibility is to have the moving surfaces of a sailplane painted in a dark colour - red, dark blue, brown and dark grey are some of the colour that have been tried.
It has been noted that, when the controls surface is deflected, as when making a turn, it presents a contrasting surface to any aircraft that is behind or in front.
TIPS TO ENHANCE YOUR CHANCES OF DETECTING
OTHER AIRCRAFT
COPA Flight Safety Bulletin Feb/91
The following safety tips do not come with any "iron clad" guarantee. However, if they are followed, your chances of detecting other aircraft that may be on a collision course with you will be enhanced.
If the other aircraft appears to be stuck in the same position on your windshield, you are on a collision course. If it moves you are going to miss it, but take some positive avoidance action just to be on the safe side.
You are looking for a small target which grows rapidly in size only after it is too late to be avoided. It can take a couple of seconds for you to appreciate the situation, make a response and change your course, therefore, minimize the time that you have your head stuck in the cockpit.
Concentrate your search in those areas of potential conflict, which in most situations will be along the horizon. Look for those aircraft at the same altitude as yourself.
Keep your eyes scanning the search areas in quick movements. It is impossible to move your eyes in a smooth, continuous way, unless there is something out there moving in a smooth way which the eye can track.
A pilot who cant see is an accident waiting to happen. Without good glare protection, flying on bright sunny days can be tiring and hazardous. And it can affect night flying too. Exposure to bright sunlight for a whole day without protection interferes with proper night adaptation for 12 to 24 hours! The following brief summary will focus on how to choose your sunglasses and the advantages and disadvantages of the various types.
There are three problems caused by bright sunlight: glare, infrared (IR) radiation and ultraviolet (UV) radiation. Glare, although the most obvious nuisance - causing tearing, distraction and fatigue - is responsible for less serious problems than IR or UV radiation. Cutting down glare by using very dark sunglasses, however, can cause problems because reducing transmitted light reduces visual acuity, as anyone who has driven from a bright road into a dark tunnel whilst wearing sunglasses can verify. Even moderately dark sunglasses can, on a bright day, cut your vision down from 20/20 to 20/40.
On the ground, UV is partially filtered by the earth's atmosphere, but the higher you go, the less the protection. UV light is not filtered equally by all types of sunglasses and can damage the eye, causing early cataracts (lens opacities). Clear plastic sunglasses which only cut down glare allow the pupils to remain dilated in sunlight and may actually increase this risk. Good sunglasses reduce light transmission to 12-20%, but should cut down UV transmission by at least 90%. IR damage, caused by looking directly into the sun, should be avoided as IR can quickly injure the sensitive retina at the back of the eye.
Sunglasses may be constant gradient, photochromic or polarized. Polarized lenses are great for fishing but bad for flying. Due to manufacturing stresses, there may be small areas of polarization in an aircraft canopy or windscreen and, if the angles of polarization in the glasses and the windscreen differ, a blind spot can be produced. Polarization may also interfere with depth and distance perception, particularly during a bank. Just what you need turning on final!
Photochromic lenses which darken with increasing UV light are good for driving, but polycarbonate aircraft canopies shield out much of the ultraviolet rays and may interfere with their proper darkening. Additionally, going from bright sunlight into cloud the glasses may take several minutes to lighten.
Constant gradient glasses come in various colours and are the most commonly used. All are about equally effective for glare, but green or grey lenses have the least adverse effect on your vision. Yellow lenses are good in haze, but less effective in bright sunshine. Sports orange lenses should not be chosen because they interfere with blue green discrimination and may make red warning lights more difficult to see.
What is best? Where vision is concerned there are numerous cheap sunglasses, but few good inexpensive ones. Constant gradient lenses which reduce light transmission to 15-20% and block 90% of UV are ideal. Plastic lenses are lighter in weight, and sometimes less expensive, but tend to scratch. Neutral grey, green or brown lenses are the most popular. Blue, orange or polarizing lenses should not be worn while flying. If in doubt, ask an optometrist or your eye doctor. in the long run, it is wiser to save your eyes than to save your money!
SEE AND AVOID
statistics from Canadian Airspace Newsletter 2/92
Did you realize that pilots need a total of 12.5 seconds to avoid a collision? That is what an American military study concluded was necessary to avoid a collision. That is a lot of time! In 12.5 seconds two sailplanes on a head-on collision course traverse about 0.7 - 1.0 km, assuming closing speeds of 200 - 300 km/hr.
The researchers determined that the 12.5 seconds are broken down as follows:
0.1 seconds to see the threat
1.0 seconds to recognize the threat as an aircraft
5.0 seconds to perceive a collision course
4.0 seconds to decide how to avoid the collision
0.4 seconds for the pilot to move the controls
2.0 seconds for full response from the aircraft.
SUNGLASSES AND POLAROID PROBLEMS
[Canadian] Aviation Safety Letter (unknown issue)
"It was bright but hazy with 40 miles plus visibility. Radar advised me of an aircraft at the same altitude which was slowly overtaking on my left side. Soon it was reported at 9 o'clock and three miles. The sun was behind me. It was near noon. I couldn't see the traffic until I slipped off my polaroid clip-ons and suddenly the image of the other aircraft snapped sharply into view with considerable contrast against the hazy background.
When I put the polaroids back on again, it was a moment or two before I could find it again since there was almost no contrast between the aircraft and sky."
Our Aviation Medicine experts explain this phenomenon:
Sunglasses reduce solar glare from direct, reflected and scattered sunlight. Glare may cause both discomfort and reduced visual acuity. The ideal sunglasses for aviation are neutral grey in colour to avoid affecting colour discrimination, and have a luminous transmittance of between 10 and 15%, that is, they will filter 85 to 90% of the glare effect.
Polaroid lenses are constructed by placing a matrix of minute dichroic (double refracting) crystals between two pieces of glass. The matrix is oriented so that the lens acts as one large crystal which polarizes light in one direction, usually in a horizontal plane. They are therefore very effective in reducing glare. However, since aircraft windscreens are usually made of laminated glass, the combination of a laminated windscreen and a polaroid lens may produce polarization of light in two planes, thus effectively blocking vision.
BETTER GET RID OF THE CHEAP SUNGLASSES,
DILBERT! (c)
[Reprinted with the kind permission of the Aviation Safety Institute]
Edited for Safety FAQ
(Editor Note: This good article was written by Lt. David M. Kennedy (USN), VA-27, appearing in APPROACH Magazine, September 1984. Our thanks to Lt. Kennedy and the Navy Safety Center for the availability of this article. We commend it to your reading).
AS naval aviators, we like to look good. We're also very interested in protecting our precious assets; our "family jewels," so to speak. That's where a solid safety program, thorough preflights, steel toes, NOMEX (Ed: fire resistance flight suits) and sunglasses come into our lives. Sunglasses? Yes, SUNGLASSES. They protect our eyes while producing that unmistakable look that civilians are always trying to copy. But - be honest - how much do you REALLY know about your favorite shades? You wear them as much off the job as on; yet, you probably know very little about what they'e designed to protect you against or exactly how they do it.
First, a little aviation physiology. The sun can do some bad things to your eyes. The known mechanisms of damage are glare, ultraviolet radiation (UV) and infrared radiation (IR). GLARE is the amount of visible brilliant light your eyes have to handle, such as direct light on a sunny day, reflected light from snow or water, or the blinding light from an F-14 burner cat (Ed: catapault) shot at night. Glare can be discomforting or disabling, normally interferes with vision, and individuals have differing sensitivity to differing glare intensity levels. ULTRAVIOLET rays are invisible, potentially harmful and increase in intensity with an increase in level of visible light. UV radiation is the principal cause of high altitude snow blindness and is linked with development of cataracts. INFRARED rays are the sun's heat rays, are also invisible and are a potential cause of retina burns and blindness - (one of the reasons for the warning not to look directly into a solar eclipse even when wearing dark tinted sunglasses). The cumulative effects of glare, UV and IR radiation are fatigue, discomfort, squinting, tearing, distraction and a loss of night vision and dark adaption. Concerning dark adaption, the American Optometric Association counsels that "people who spend an entire day in bright sunlight will not regain their normal night vision even after a full night. Those who spend every day in the sun may require from several days to two weeks of non-exposure to totally regain their normal night vision."
Ideally, sunglasses should provide protection as well as comfort for the wearer -- in our case, the intrepid naval aviator. The rugged, stylish look is just one of the fringe benefits of choosing the "right profession." In flight, the tinted visor, alone or in conjunction with issue sunglasses, works with canopy plexiglas (a UV shield) to provide the required protection. On the ground or at the beach, sunglasses and informed good sense do the job.
The major types of sunglass lenses are CONSTANT GRADIENT, POLARIZING, PHOTOCHROMATIC, REFLECTING and a combination of the previously named types. CONSTANT GRADIENT or TINTED lenses are fixed in color and the amount of ambient light they allow to be passed. They come in various colors, the most popular being gray, green, brown and amber. Although the color of the tint has no effect on the lens' ability to block or absorb UV rays, it does affect the lens' ability to absorb IR rays. The lens' color also affects color perception. POLARIZING lenses absorb some of the light rays reflected from horizontal surfaces, especially water, snow, and sand. Their glare-reducing effectiveness depends upon the light-to-lens angle of incidence. PHOTOCHROMATIC or CHANGEABLE lenses are made of light-sensitive glass which automatically adjusts in density to the level of brightness. Most depend upon UV rays to trigger the darkening reaction. REFLECTING or MIRROR lenses are tinted lenses with a thin metallic coating applied to further reduce light transmission. The coating may be applied to the entire lens or only to the top and/or bottom to combat intense overhead and/or reflected glare.
The only sunglasses authorized for inflight wear by Navy aircrews are the familiar "FG-58" (Flight Goggle 58), introduced in 1958 by American Optical and equipped with neutral gray lenses that block all but 1-18 percent of the ambient light. (This, from the MILSPEC). Neutral gray lenses are stipulated because they don't distort or change colors as most colored lenses do. All things considered, the FG-58 is an excellent pair of sunglasses. Polarized lenses are specifically not authorized for inflight wear due to the possibility of blind spots caused by the cumulative polarizing of canopy/windscreen, visor and sunglass lenses. Photochromatic lenses are not authorized in flight because they are not considered dark enough, even at their darkest, to provide adequate protection. Lenses whose changing density depends upon UV rays are also hampered by the canopy's absortion (sic) of UV rays.
Although naval aviators are encouraged to shun commercially obtainable sunglasses in favor of the FG-58, a simple glance around any naval air station will show a wide variety of sunglasses, most of which are excellent. Some, unfortunately, don't provide the wearer with adequate protection and may be potentially dangerous. By filtering out glare and by tinting the lens, some substandard sunglasses allow your natual squinting impulse to relax and your pupils to dilate. As a result, your eyes become susceptible to retina-damaging IR and UV radiation.
How can you -- the intrepid naval aviator -- best evaluate those shades you're thinking of buying? Only a few manufacturers publish vital statistics with their sunglasses, but those with the best quality lenses do or will gladly provide the information. Additionally the National Society for the Prevention of Blindness suggests several criteria, among them:
1. TRANMISSION FACTOR. For persons engaged in bright work outside or who contemplate night flying, the experts recommend lenses that block 85-90 percent of sunlight, allowing 10-15 percent to reach the eyes.
2. UV TRANSMISSION. The amount of ultraviolet radiation blocked by the sunglass lens varies widely, but all quality lenses rank high in this important category. Studies continue in order to determine the effect of even small amounts of UV radiation over long periods of time.
3. IR TRANSMISSION. Like UV radiation, quality sunglass lenses rank high in this category, measured in terms of IR radiation blocked.
4. COLOR. Neutral gray (or "smoked") is the lens color that retains color fidelity best, but there are advocates of green and brown lenses. The transmission curves of green lenses resemble the color sensitivity of the eye, while brown lenses block scattered blue light rays prevalent with dust or moisture in the air, thereby reducing haziness, improving contrast and sharpening details.
5. OPTICAL QUALITY. Both lenses of your sunglasses should be evenly matched, equal in color and absorptive qualities. The lenses should be free from waves, surface blemishes, scratches or other distortions that can cause eyestrain. To test the lenses, hold the glasses at arm's length, focusing on a distant vertical line. Move the glasses vertically and horizontally. If the line waivers, the lenses contain distortions and should not be used. However, this test is NOT valid for prescription lenses.
6. IMPACT RESISTANCE. The Federal Food and Drug Administration requires that all eyeglass lenses -- including sunglass lenses -- be made of impact-resistant glass or plastic.
The following chart indicates how several popular commercially obtainable sunglasses compare. In no way should be considered complete, or as an advertisement. Optical quality standards of the type set out below, and not mere style and price, should be your guide when buying sunglasses. Also make SURE they are impact resistant.
| Sunglasses | Colour/Type Lens | Transmission (%) | UV (%) | IR (%) |
| FG-58 (American Optical et al) | constant density, neutral gray, N-15 | 15% | 99.8% | 85% |
| Ray Ban Outdoorsman/aviator | Constant density, neutral gray, G-15 | 15% | 99% | 85% |
| Bausch & Lomb | Constant density green | 26% | 99% | 95% |
| Bausch & Lomb | Constant density brown | 15% | 99% | 95% |
| Bausch & Lomb | Reflecting + neutral gray G-31 | top: 4%; center: 23% | 99% | 90% |
| Vuarnet Skilynx Acier (Vuarnet-France) | Reflecting + brown | top: 7.7%; center: 12.2%; bottom: 6.5% | 100% | 90-99% |
| Fishing glasses (Eddie Bauer) | Polarizing | 25% | 84% | 70% |
CAUTION: Although some manufacturers suggest that certain lenses with particularly high transmission factors are "light" enough for use indoors, or while driving at night, such a practice is bad headwork! So, next time you select a set of shades, use these standards of judgment -- and if the bargains you're picking up don't pass, you'd be smart to consider just how much those "cheap sunglasses" might be costing you!
Acknowledgment is given to the National Society for the Prevention fo Blindness, American Optometric Association, Better Vision Institute, Bausch and Lomb, Vuarnet-France, American Optical Company and Navy Opthalmic Support and Training Activity.
(ASI Note: Thanks to Lt. David M. Kennedy for an informative and well-written article.)
LIGHT POLARIZATION AND SUNGLASSES FOR PILOTS
From the internet
This article is written in order to explain the basis for various statements and comments about polarized sunglasses as they apply to aviation. Below are a couple of specific examples that will be addressed in the text following them. My hope is that this article will lead to broader understanding of polarized light effects pertinent to aviation.
Anecdote from the: "SUNGLASSES AND POLAROID PROBLEMS" [Canadian] Aviation Safety Letter (unknown issue) :
"It was bright but hazy with 40 miles plus visibility. Radar advised me of an aircraft at the same altitude which was slowly overtaking on my left side. Soon it was reported at 9 o'clock and three miles. The sun was behind me. It was near noon. I couldn't see the traffic until I slipped off my polaroid clip-ons and suddenly the image of the other aircraft snapped sharply into view with considerable contrast against the hazy background."
Comment from the "BETTER GET RID OF THE CHEAP SUNGLASSES, DILBERT! (c)" article by Lt. David M. Kennedy (USN), VA-27, appearing in APPROACH Magazine, September 1984. :
"Polarized lenses are specifically not authorized for inflight wear due to the possibility of blind spots caused by the cumulative polarizing of canopy/windscreen, visor and sunglass lenses."
POLAROID SUNGLASSES
Polaroids are made of materials typically based on polyvinyl alcohol with iodine or some dyes incorporated into it. These materials exhibit linear dichroism with the direction of the absorbed polarization being set into polaroid sheet by an anisotropic stretching process. In that process the long polyvinyl alcohol molecules are oriented along the stretch direction, and thus the incorporated iodine or dyes become anisotropically active. Good polarizers fabricated this way transmit more than 80% of one polarization while essentially completely eliminating the other. Typical field of view of human eyes is +-35 degrees from the normal to the glasses. For all practical purposes one can consider light viewed through polaroid sunglasses to be incident perpendicularly to lens surface, and dispense with extra complications in discussion.
Most, if not all polaroid sunglasses sold in the stores are set to transmit light polarized vertically (in the frame of a standing person wearing the glasses). This suppresses glare caused by sunlight reflecting off a rear window of a car which is being followed, to darkening of sky toward the zenith when the sun is behind an observer wearing the polarizing sunglasses, and reduces haze with the sun overhead.
POLARIZATION VIA SCATTERING
Direct sunlight is unpolarized. As it traverses the atmosphere it is scattered within it by air molecules, small particles, molecules or tiny droplets of water and so on. For the most part this scattering is strongly, but smoothly, dependent on the wavelength of light. Blue light scatters roughly five times stronger than the red; thus the blue sky. Small particles (smaller than two tenth of a micron in diameter) scatter unpolarized sunlight more or less equally in all directions. However, as the scattering angle approaches 90 degrees the light becomes strongly polarized in the direction perpendicular to the scattering plane. This is strictly true for a "single scattering event". In the atmosphere, light often undergoes multiple scattering events before reaching the observer, thus the polarization due to this effect is not perfect.
Looking through polarized sunglasses perpendicularly to sun rays, an observer with sun behind him will find a band of darker sky. This effect is often used by photographers to increase the contrast of clouds against the sky. This also benefits a glider pilot who is looking for a small whisp of a cloud against the sky's background. When the sun is near to horizon the polarized band is overhead. At noon, with the sun nearing zenith, the polarized band moves towards the horizon. As an observer samples a greater distance through the atmosphere, multiple scattering effects become more important and the degree of polarization is lowered for a band close to the horizon.
The same effects are observed with scattering due to haze. As long as the haze is thin, the scattered light can be eliminated by polarized sunglasses (mostly single scattering events). However, as the haze thickens, multiple scattering destroys the polarization of light coming from further away. Polarized sunglasses now help only with the light scattered close to the observer. As the haze thickens even more, the light from the sun becomes diffuse enough to render polarized sunglasses completely ineffective.
So what is the explanation of the observation in the above anecdote?
I'm going somewhat on a limb but: The sun is overhead (near noon) somewhat to the back, haze is weak (more than 40 miles visibility). The observer is looking for an aircraft to his side, reasonably close to him and near horizon. Aircraft in this configuration does not reflect a lot of light so it is going to be basically a small, dark object against the background. But what is the background? With polaroids on, the observer eliminated light scattered by the haze and suppressed somewhat the intensity of the sky. So he is looking for a basically dark object against darkish background within a predominantly bright scene. I believe that this is one of the worst cases possible for noticing an object. The moment he takes off his polaroids the background lights up increasing the contrast significantly.
But what if the aircraft one were looking for presented itself as a bright object, (e.g. had its lights on, was in a turning bank so that it reflected more light towards the observer). My guess is that the polaroid sunglasses could help in such a case.
POLARIZATION VIA REFLECTION AND TRANSMISSION
About 4% of light incident perpendicularly at a glass surface is reflected on each glass-air interface. As the angle of incidence (half the angle between the incident and reflecting rays) increases, the reflectivity of light polarized perpendicularly to the plane of incidence (plane containing incident and reflecting rays) (s-polarization) increases. However the reflectivity of the light polarized in the plane of incidence (p-polarization) initially slowly decreases, and at a specific angle (Brewster angle) which for glass is about 56 degrees, it reaches zero.
For larger incidence angles, reflectivity of the p-polarized component rises rapidly but is always smaller than that of the s-polarized component until, at glancing incidence (incidence angle approaching 90 degrees) light is completely reflected. At Brewster angle the reflected (not transmitted) light is completely polarized. The reflectivity of the s-polarized component at Brewster angle is about 15% per surface (thus about 70% of this polarization of light is transmitted through a sheet of glass compared to 100% of the other). Metallic surfaces strongly reflect both polarizations.
It is now easy to understand why polarizing sunglasses help eliminate glare from a rear window when one follows a car. With the sun overhead, light reflected from glass surfaces of a car ahead is largely polarized in the plane horizontal to the observer, and that is the polarization that the polaroids absorb. Light reflected off of smooth paint is also to some extent polarized and glare from painted parts can be also suppressed. Note that a slanted windshield of the observer's car also acts as a polarizer (though a very poor one) which is oriented in the same direction as the polarizers of the sunglasses.
What are the implications of that for pilots? I am not sure. In general there appears to be concern about "blind spots" created by cumulative polarizing effects of windows, visors and sunglasses (the windshield effect described above). I do not think this is of any concern for any normal viewing situation. The polarizing effects of the intervening surfaces parallel those of the polaroids. I can imagine however some abnormal viewing conditions in which a "blind spot" might be created, e.g. a pilot tilts his head significantly to look backwards. "Blind spot" in such a case would mean almost total darkness, not loss of contrast. This problem would be exacerbated by a double paned window with an air gap inbetween. Window laminations do not contribute to polarization of light as the bonding materials are usually optically well matched to the glass they join. In my opinion, the "blind spot" effect may be of some concern to fighter pilots in combat, but I doubt very much that they are of any importance to an average pilot; even to a glider pilot who twists his head in a gaggle.
I would be more concerned with a different effect. As mentioned above reflection off paint can be polarized. More often than not I notice other gliders as they flash their wings in a distant turn. With the sun overhead this flash might be lost should I be wearing polaroids.
MY PERSONAL CONCLUSIONS ABOUT USING POLARIZING SUNGLASSES IN FLIGHT
Well, I do not think I want to use them. The variation in their effects is just too great. They definitely help in some situations (e.g. increase contrast of light objects against the sky, help see deeper into haze), but then there are also situations that they might be detrimental (see the anecdote above). In my opinion a pilot is better served by using sunglasses which eliminate the deep blue and thus achieve most of the positive effects of the polaroids by eliminating the radiation that is easiest to scatter, and at the same time help somewhat the visual acuity by limiting chromatic aberration effects (light of different colors comes to focus at different distances from a lens) in the eyes. The UV protection they may offer would be another, and maybe the most important benefit.
THE LANDING FLAREOUT (c)
[Reprinted with the kind permission of the Aviation Safety Institute]
Some pilots have difficulty with the last five to ten feet of altitude just as they progress through the flareout maneuver. It would be well to consider what can be done to improve the flare technique. (Obviously, to judge a pilot primarily on his or her flare skill is not fair.)
It is a well-tested theory that pilots who maximize the use of their extrafoveal or peripheral eye retina during the flare phase generally land better. The use of the peripheral vision results in two important assessments: 1) location in space above the runway, and 2) estimation of vertical speed -- up or down.
Let us assume, a priori, that there is sufficient intelligence out in the real world to give you the cues for making the flare maneuver. When snow cover is covering the runway and lighting environment, or when landing at night with no lights to assist (an unlikely event in today's flying environment), the necessary cues may not be there.
There is normally adequate visual intelligence external to your field of fixated vision, but still within your general view. This is much like having the experience of gazing at an object, and at the same time being aware of something else moving out of the corner of the eye.
The extrafoveal or peripheral retina is particularly sensitive to movement, and, as long as any vision remains, we have movement perception. The readiest explanation of our sense of movement is the successive stimulation of receptors leaving a trail of "on/off" discharges in the eye which gives some indication of direction and total displacement. (Wyburn, Pickford, and Hirst, 1964).
Tests reported by Majendie (1960) demonstrated that significant visual cues were received by pilots landing, from the dynamic pattern of the runway environment. Quoting ."furthermore, it was shown by photographic methods that the pilot did not use a pattern of fixation to assess these cues, but stared fixedly ahead, allowing the dynamic part of the pattern to stream across his field of vision..."
It is not clear what the origin is of this theory. Calvert (1954) credits Majendie for such a suggestion in a personal communication in 1949. However, in passing we might observe that earlier published reports by other investigators (.e.g, Grindley, 1942, Gibson, 1947) certainly dealt with the Parafaveal Streamer Theory of visual judgments made from an aircraft in motion, although they did not use the same terminology.
Sounds technical ? True, but we are giving you a list of references should you want to review the "older" literature -- the basic work that has been done on use of peripheral retina in flying.
Let us consider the task of flaring. The aircraft's speed at the point of entry into the flare maneuver is crucial. Being too slow or fast will profoundly effect the point of touchdown, and your total landing distance, as well as the control applications you apply to touch down for minimum vertical speed and good runway alignment.
We recommend that you bring the aircraft over the runway threshold no faster or slower than 1.3 times the power off stall speed. This would be 1.3Vso. You can determine Vso quite simply for your aircraft by doing a smooth, gentle power off stall(straight ahead) and reading what your airspeed indicator reads at the speed at which control is "lost". This is called the "minimum control speed", which is essentially equivalent to Vso. Multiple that indicated value by 1.3 and you have an acceptable speed over the "fence". Of course, you should add a knot or "MPH" for each knot of headwind speed over 10 knots. This will help keep the aircraft away from the stall regime due to turbulence on final.
Once at that speed and aligned with the aiming point you have chosen on the runway, you should cross the threshold at 1.3 Vso and begin your flare approximately 10 feet above the runway. You should, by now, have fixated on a point near the horizon line easily seen from your position in the cockpit. You may then sense any changes in position above the runway by the apparent motion of the runway edge environment. That is, if the runway edge appears to come up rapidly, you are sinking at the same rate, and you must apply appropriate elevator movements (and-or power) to reduce the rate of sink. Similarly, you should quickly observe any drop of the runway edge environment and take equally appropriate and timely action.
Do not make the common mistake of fixating on the runway below you. To do so will DESTROY the use of the peripheral retina faculties, and you will not effectively observe position changes and vertical rates. We recommend that you try this technique, probably with an instructor or competent pilot aboard as a safety pilot.
Calvert, E. S., Visual Judgments in Motion. Journal of Institute of Navigation, 1954, 7, 233-251.
Gibson, J. J. (ed). "Motion Picture Testing and Research". Amry Air Force Aviation Psychology Reports, Report 7, 1947.
Grindley, G.C. , "Notes on the Perception of Movement in Relation to the Problem of Landing an Airplane". Air Ministry Flying Personnel Research Committee, Report FPRC 426, 1942.
Majendie, A.M.A., "The Para-Visual Director", Jounral of Institute of Navigation, 1960, 13,447-454.
Wyburn, G.M. , Pickford, R. W., and Hirst, J.J., "Human Senses and Perception", Edinburgh and London, Oliver and Boyd, 1964.
Edited for Safety FAQ
The Grob G102 glider has a clear Plexiglas canopy and a black interior, which in the case of strong sunshine can produce a significant greenhouse effect. The pilot normally carried one and one half litres of drinking water when flying in his own glider. However, no water was available in the Grob. The pilot had eaten porridge for breakfast, consumed some fruit for lunch, and had drunk about three glasses of water while working on the flight line. He recalls being hot and tired during the flight. Aircrew rarely experience dehydration by itself, but rather more commonly encounter dehydration in combination with heat stress. Heat stress generally results from rising environmental temperatures and/or increased physical workloads, causing a rise in body temperature. Part of the body's response when heat stress is high is perspiration. The evaporating moisture is an effective cooling mechanism. However, when body moisture is not replenished, dehydration can result. The sweating mechanism can then become ineffective, and the body temperature will continue to rise.
Unchecked heat stress can lead to three conditions of increasing hazard level: heat cramps, heat exhaustion, and heat stroke. Performance affecting symptoms, including loss of concentration or focus on tasks and increasing irritability, become increasingly evident as the body continues to store heat. At low levels of heat stress, the effects on an individual's performance are more subtle, and a pilot being affected may not realize it at the time.
HYPOGLYCEMIC ATTACK CAUSES CRASH
[Canadian] Aviation Safety Letter 5/90
Approximately 45 minutes into a cross country flight, while flying at 4,000 feet above ground level, the pilot felt dizzy and then lost consciousness. He awoke as the aircraft was descending in an unusual attitude toward trees. The pilot was unable to recover from the unusual attitude, and the aircraft flew inverted into the trees. He survived and made his way back to civilization, and was admitted to hospital for tests.
Routine testing showed nothing amiss, but a medical specialist digging into the pilot's history learned that he was a regular consumer of alcohol. His hypothesis was that the pilot suffered a hypoglycemic attack due to fatty-liver disease. The pilot had only toast and coffee in the 18 hours prior to the accident, and a drink of grape juice just before departure. The high sugar content of the grape juice probably triggered the hypoglycemic reaction due to the pilot's liver condition.
Your liver may be in perfect condition, but you can still have hypoglycemic symptoms by not eating adequately prior to going flying, or eating foods that give quick energy (eg chocolate bars) but later lead to feelings of light- headedness, stomach upset and disorientation.
Remember to eat a substantial meal, high in protein, that provides long-term energy - it will make your flying more comfortable.
HEALTH AND WELFARE CANADA COMMENTS ON
ASPARTAME
Canadian General Aviation News Oct/90
In the March 1990 issue of Canadian General Aviation News in this column, a pilot outlined his concerns over questionable adverse effects from the
consumption of diet drinks containing aspartame.
As a result of the article, Health and Welfare Canada referred the pilot's comments to the Bureau of Chemical Safety, Food Directorate. Their finding indicate that aspartame is not a problem for most individuals. They point out that aspartame is composed of two amino acids, aspartic acid and phenylalanine, which are normal constituents of proteins. Aspartame is metabolized inexactly the same manner as any other food protein in the diet. In regard to the formation of methanol, it has long been known that methanol is formed upon degradation and metabolism of aspartame. Methanol however, is not foreign to the human diet. Many common foods, including fruits and fruit juices contain low levels of methanol and substances that are metabolized to methanol. For example, it has been calculated that degradation of all the aspartame in one litre of a soft drink would result in about the same amount of methanol as would be ingested from the consumption of two medium sized apples.
Since the use of aspartame was permitted in Canada, The Health Protection Branch has received as few reports, mostly unsubstantiated, of adverse reactions to this substance. These were generally in the nature of headache, and so called "general malaise" which could not be definitely attributed to aspartame ingestion.
There is however no question that some people do exhibit allergic reactions or hypersensitivities to specific food additives such as aspartame. Monosodium glutamate is a good example. This is the reason that there is a requirement for labelling of the contents of food and beverage preparation.
Dear Editor,
I noted from a recent article in Radio Control Models & Electronics that the author, whilst flying a model helicopter, had experienced a disorientation problem which he accidentally found was related to drinking "diet" soft drinks. Some time later (after laying off the soft stuff) he read a report in the Experimental Aircraft Association's magazine Sport Aviation (February 1985 issue) which explained the problem which could have a lot of relevance to our own sport.
The report, written by Dr. Stanley R. Mohler, concerned a substance called aspartame. This is marketed under the brand name "Nutrasweet" and used in a number of soft drinks. The report states that ... "I found that there are numerous reports by persons who have experienced visual impairment, dizziness, loss of equilibrium or disorientation following its use". The effect is attributed to an allergic reaction which some people may have to the methanol which is produced when aspartame breaks down in the body. The report concludes: "I'am not advocating that you don't drink diet soft drinks - but if you do develop headaches, dizziness, blurred vision or other symptoms, these may be associated with the diet drink. Just be aware of this".
Recently a letter was sent to COPA (the Canadian Owners and Pilots Association) in which a pilot expressed his concerns over questionable adverse effects from consumption of diet drinks containing aspartame. By 1986, the FDA and the Centre for Disease Control in the USA had evaluated 3000 known complaints. Fellow pilots who may have had similar side effects may be interested in the information below.
Plane and Pilot magazine featured an article on drugs and alcohol vis'ê'vis safe flying practises that also talked about food additives. It explained that diet soft drinks are sweetened artificially by "aspartame" (with brand names NutraSweet and Equal), and that aspartame contains 10 per cent methanol. That caught my attention! I know that methanol (sometimes called wood alcohol) is a poisonous substance, which on ingestion causes blindness and death; two teaspoons full are considered lethal.
The article disclosed that methanol destroys the brain, albeit a little at a time, and that effects are cumulative. Depending on a persons physical state and tolerance level, immediate effects can either be severe (resulting in epileptic seizures, including grand mal, blindness, chest palpitations), or less noticeable (causing blurred vision, "bright flashes", tunnel vision, ringing or buzzing in ears, migraine headaches, dizziness, loss of equilibrium, lip and mouth reactions). Less noticeable effects might be passed off as temporary or caused by something else. But everyone is affected in one way or another, since methanol causes toxic reactions, not just allergic ones, in a few unfortunates.
Here are direct excerpts from the article:
"An Air Force pilot traced the patterns of tremors and seizures he suffered for two years directly to his patterns of NutraSweet consumption. When he travelled to areas where diet sodas were not available, he was free of the symptoms. But when he resumed intake of the beverages, his tremors resumed, grew more severe and culminated in a grand mal seizure that ended his flying career. His medical problems ceased when he quit ingesting NutraSweet, but it was too late to restore his flying status."
"Another pilot suffered similar symptoms only when using aspartame products. But FAA revoked his medical certificate when it was informed of the symptoms. After only two cups of artificially sweetened hot chocolate, a pilot experienced blurred vision so severe he was unable, in flight, to read the instruments and very narrowly avoided a tragic landing. Safely on the ground, he related his symptoms to the secretaries in his office. Both of them told of experiencing similar symptoms after ingesting aspartame products."
I, too, had bad experiences with aspartame. It replaced saccharin about 10 years ago; as a marathon runner in my 30s I consumed litres of diet drinks daily at that time. When I first drank pop with aspartame, it had immediate and severe effects upon my consciousness and vision. After a few scary incidents, pop consumption and problems seemed related.
I described symptoms and circumstances to my doctor. He ran tests, but never seriously listened to my concern of relating pop with the effects. He was a reasonably competent GP, but not ready to distrust, let alone blame, an FDA approved sweetener. Eventually I quit ingesting aspartame and have not had incidents since. Employed in the professions and a post-graduate, I conduct research occasionally and am aware of the difficulty of matching cause and effect (and the danger of doing it improperly). But there is no doubt in my mind that "tests" with my body proved that aspartame is bad (at least for me).
Apparently the other main components of aspartame, phenylalanine (50 per cent) and aspartic acid (40 per cent), combined with the methanol (10 per cent), create a witches brew of 16 breakdown products after digestion that cause illness. Animal tests revealed brain tumours, some cancerous; holes in the brain, womb tumours, uterine tumours, and reproductive dysfunctions. Studies on humans indicated that pregnant women and young children run especially high risks.
If pilots want more information, I encourage them to call The Aspartame Consumer Safety Network in Dallas, Mary Nash Stoddard, (214) 352-4268. ACSN promises confidentiality if asked, and will send an eye-opening information package.
Comment by Dr. Peter Perry
Chairman, SAC Medical Committee
This is an interesting article on aspartame and methanol and their side effects, all of which are quite valid. I am sure the aim of the article was to increase pilot awareness of the same. However, I think it has been taken out of context, so to speak, and we have to put the information in the proper perspective. The writer of the article and, I am sure, the other people he has spoken to did indeed have those alarming symptoms, so other users of aspartame should be aware of that possibility, particularly pilots.
If one looked at the full range of side effects of Aspirin and Tylenol, to take two other over-the-counter drugs as an example, one probably wouldn't dream of taking them because they can both produce a wide range of serious side effects, some of which can even be fatal. Even regular coffee is not to be taken lightly - I have seen one authority write that the consumer would be unfit to drive a car after two cups.
Aspartame and the other drugs mentioned have been around for quite some time. They have nasty side effect profiles. But millions of "doses" have been taken. So what is the bottom line. The important thing to consider is not the possibility but the probability of an adverse reaction occurring (bad side effects have low probabilities). Luckily, all the specific cases referred to in the article had dramatic side effects with rapid onset, making it easy to recognize and so respond appropriately. Often we are at more risk from medications with insidious onset of reactions, such as cold remedies and sedating antihistamines, to say nothing of alcohol, smoking, and hypoxia.
ARE YOU A JELLY DONUT?
[Canadian] Aviation Safety Letter (unknown issue)
If it's true that "you are what you eat", then how many of us must stand up and be counted as bacon sandwiches, french fries and jelly donuts?
If you want to stay healthy, you have to give your body the materials it needs to do the work - to produce energy, remove toxic by-products and regenerate itself. Flying puts special demands on you, particularly at high altitudes. The cabin is dry, the temperature tends to be uncomfortable and hypoxia occurs, even in a pressurized cabin which is normally kept between 5000 and 7200 feet. The success you have combatting the stress of this environment depends on your life style - getting the proper rest, exercise and of course nutrition.
The average North American eats too much sugar, too much fat, too much salt and too many refined carbohydrates. The food is nearly always cooked, often overcooked and too often deep fat fried. One nutritional expert suggests, "Avoid as much as possible those foods which have been refined or processed and that contain food additives and chemical pollutants. Foods that increase the likelihood of disease should be avoided, including sugar, white flour, hydrogenated fat, food preservatives and the many artificial flavouring and colour agents."
Airline doctors and aerospace physicians give the same advice. "Crosscheck", a Pan American magazine for pilots, suggests they eat no refined carbohydrates, including sugar and all refined starches. Instead it suggests protein-rich meals eaten every four hours, especially when on flight duty, with fruit or protein snacks for pick-me-ups at odd duty times. It recommends eliminating coffee and soft drinks in favour of low fat milk or fruit juice.
Simply stated, "if many made it, don't eat it" or, more to the point "eat only those foods that spoil. rot or decay, - but eat them before they do."
The secret is not only eating right, but knowing what's good for you. It's a good idea to do some reading on nutrition and if you suspect your present diet many be inadequate, consult a specialist.
Eating regular, healthy meals can be quite a challenge, especially when you're flying the irregular, unpredictable hours of the flying instructor or charter pilot. It's worth the extra effort though. A good start would be to make a habit of keeping a few apples, nuts, and raisins in your flight bag. These will keep you away from those dreadful candy bar machines in airport terminals.
Think of food as your body's fuel. Would you expect your aircraft to perform properly if you ran it continuously on a lower grade fuel than it was designed for? Would you anticipate completing a long cross-country flight if you took off with the fuel low level lights on? If you want to perform at peak efficiency, be particular when you fill your body's "fuel tank". You owe it to yourself as well as your passengers.
QUENCH YOUR FATIGUE
[Canadian] Aviation Safety Letter (unknown issue)
Plain old fatigue can happen from many causes. But one if the most treatable is dehydration. Consider the following:
-we lose about a litre of water a day through normal excretion;
-in hot weather, sweating can cause the loss of up to an unbelievable 4 litres in an hour (In the cockpit, we won't lose that much, but we may lose quite a lot);
-the dehydration effect of pressurization systems (where the humidity can be lower than that of the Sahara Desert); And then there's altitude. As we go to altitude there's less nitrogen, less oxygen, and less water too. The tendency is for the human body to try to share its water with that virtually waterfree atmosphere.
Water loss from low humidity at altitude increases "insensible" perspiration - insensible because we don't notice it. We could call it evaporation just as easily. Our bodies, which are 75-80% water, are like a wet sponge on the desert, continually losing water through evaporation. The rate of insensible perspiration increases when the body goes to altitude.
A lot of dehydration is self-imposed because we probably don't drink enough water in the first place. When the human body gets thirsty it's already about a litre low - drinking sweetened drinks is sometimes the last thing the body needs at this point.
How many of us routinely ask for and drink water with our dinner? Not many ... Why? Because we want something sweet, right? Sure, like cola, ice tea or coffee, milk, etc., in fact almost anything but water. When the human body gets thirsty, sugar can complicate the absorption of water. (And alcohol and coffee can cause the body to lose more water than it gains.)
As if things weren't bad enough, thirst tends to diminish at altitude. Your body, which was created to survive on earth, usually loses most of its water by sweating - not by insensible perspiration. As we sweat on earth, we lose not only water but other body chemicals called electrolytes or "salts". The amount of salt and water lost in the sweat changes the concentration of salts left in the blood. As the blood flows through the brain, it detects the change in salt concentration and decides we've been sweating and have lost some water. Therefore, we must be "thirsty". For pilots, the mechanism must be delayed by the fact that the change in salt concentration is not as dramatic when we lose water through insensible perspiration .. so thirst lags behind. Why haven't we dried up like a piece of jerky by now? Fortunately, we get water in our food and our body produces water as a byproduct of cell respiration. Put those with the water we get the hard way through sweetened drinks, etc., and we manage to stay alive, but we're usually walking around in an almost freeze-dried state. There's no doubt that this dehydration makes us feel fatigued.
Even the early stages of dehydration can lead to emotional alterations and impaired judgment - not the sort of changes that go well with flying. Fatigue through dehydration must be recognized be each pilot and treated - stop and take a couple of swallows of water. Drink more water and quench that fatigue.
THE HANGOVER
[Canadian] Aviation Safety Letter (unknown issue)
No session of "hangar flying" is complete without some "hero" describing the accomplishment of a terrific aeronautical feat while burdened by a massive hangover. Although the air regulations and company operations manuals outline the minimum time from bottle to throttle, little is said about the hazards of flying with a hangover. Studies have shown it can take up to 30 hours for the body to rid itself of all alcohol and the residual symptoms of heavy drinking. In fact, hangovers can affect a pilot's performance just as much as drunkenness.
For those who are not already familiar with them, here are some of the effects that can linger "the morning after".
FATIGUE - The body requires restful sleep, uninterrupted by the presence of foreign chemicals. For this reason a full night's sleep after a binge may not always be restful, even if you are convinced you slept well.
DEHYDRATION - You eliminate fluids often while getting drunk which explains the frequency visits to the washroom during the early stages of a party and the dry feeling the next morning. If you continue to drink beyond the point of intoxication, your kidneys decrease the formation of urine, fluid is retained and you awake feeling waterlogged. In any case, your body's fluid balance is disrupted by drinking and many of its other functions are also affected.
IRRITABILITY - Initially when you drink you feel euphoric. but alcohol is really a depressant. It is also a strong cardiac stimulant that makes you feel like you have had too much coffee or are under stress. The "hyper" feeling can also lead to a "pounding pulse" and elevated blood pressure, the effects of which can last up to 24 hours or more after the party has ended.
HEADACHE - The cause of alcohol-induced headaches is unclear, but one theory says that a drinker's retained fluids may dilate the blood vessels to the brain causing a "vascular-type headache". These symptoms worsen with altitude and can last much longer than 12 hours after the last drink.
The "eight hours from bottle to throttle" rule is the regulatory bare minimum but in many cases it is not enough, so use your common sense.
ALCOHOL AND FLYING IS A DEADLY COMBINATION
[Canadian] Aviation Safety Letter (1/96)
Alcoholic beverages, used by many to "unwind"or relax, act as a social "ice-breaker," a way to alter one's mood by decreasing inhibitions.Alcohol consumption is widely accepted, often providing the cornerstone of social gatherings and celebrations. Along with cigarettes, many adolescents associate the use of alcohol as a rite of passage into adulthood.
While its use is prevalent and acceptable inour society, it should not come as a surprise that problems arise in the use of alcohol and the performance of safety-related activities,such as driving an automobile or flying an air-craft. These problems are made worse by the common belief that accidents happen "to other people, but not to me." There is a tendency to forget that flying an aircraft is a highlydemanding cognitive and psychomotor task that takes place in an inhospitable environment where pilots are exposed to various sources of stress.
Hard facts about alcohol
- It's a sedative, hypnotic, and addicting drug.
- Alcohol quickly impairs judgment and leads to behaviour that can easily contribute to, or cause accidents.
- Alcohol is rapidly absorbed from the stomach and small intestine, and transported by the blood throughout the body. Its toxic effects vary considerably from person to person, and are influenced by variables such as gender, body weight, rate of consumption (time), and total amount consumed.
- The average, healthy person eliminates pure alcohol at a fairly constant rate - about 1/3 to 1/2 oz. of pure alcohol per hour, which is equivalent to the amount of pure alcohol contained in any of the popular drinks. This rate of elimination of alcohol is relatively constant, regardless of the total amount of alcohol consumed. In other words, whether a person consumes a few or many drinks, the rate of elimination of alcohol from the body is essentially the same. Therefore, the more alcohol an individual consumes, the longer it takes his/her body to get rid of it.
- Even after complete elimination of all of the alcohol in the body, there are undesirable effects - hangover - that can last 48 to 72 hours following the last drink.
- The majority of adverse effects produced by alcohol relate to the brain, the eyes, and the inner ear - three crucial organs to a pilot.
- Brain effects include impaired reaction time, reasoning, judgment, and memory. Alcohol decreases the ability of the brain to make use of oxygen. This adverse effect can be magnified as a result of simultaneous exposure to altitude, characterized by a decreased partial pressure of oxygen.
- Visual symptoms include eye muscle imbalance, which leads to double vision and difficulty focusing.
- Inner ear effects include dizziness, and decreased hearing perception.
- If such other variables are added as sleep deprivation, fatigue, medication use, altitude hypoxia, or flying at night or in bad weather, the negative effects are significantly magnified.
The chart summarizes some of the effects of various blood alcohol concentrations. The blood alcohol content values in the table overlapbecause of the wide variation in alcohol tolerance among individuals.
How alcohol affects performance
- Pilots have shown impairment in their ability to fly an ILS approach or to fly IFR, and even to perform routine VFR flight tasks while under the influence of alcohol, regardless of individual flying experience.
- The number of serious errors committed by pilots dramatically increases at or above concentrations of 0.04% blood alcohol. This is not to say that problems don't occur below this value. Some studies have shown decrements in pilot performance with blood alcohol concentrations as low as 0.025%.
Hangovers are dangerous
A hangover effect, produced by alcoholic beverages after the acute intoxication has worn off, may be just as dangerous as the intoxication itself. Symptoms commonly associated with a hangover are headache, dizziness, dry mouth, stuffy nose, fatigue, upset stomach, irritability, impaired judgment, and increased sensitivity to bright light. A pilot with these symptoms would certainly not be fit to safely operate an aircraft. In addition, such a pilot could readily be perceived as being "under the influence of alcohol".
You are in control
Flying, while fun and exciting, is a precise, demanding, and unforgiving endeavor. Any factor that impairs the pilot's ability to perform the required tasks during the operation of an aircraft is an invitation for disaster.
The use of alcohol is a significant self-imposed stress factor that should be eliminated from the cockpit. The ability to do so is strictly within the pilot's control.
Keep in mind that regulations alone are no guarantee that problems won't occur. It is far more important for pilots to understand the negative effects of alcohol and its deadly impact on flight safety.
General Recommendations
1. As a minimum, adhere to the guidelines:
- 8 hours from "bottle to throttle"
- do not fly while under the influence of alcohol,
- do not fly while using any drug that may adversely affect safety
2. A more conservative approach is to wait 24 hours from the last use of alcohol before flying.
This is especially true if intoxication occurred or if you plan to fly IFR. Cold showers, drinking black coffee, or breathing 100% oxygen cannot speed up the elimination of alcohol from the body.
3. Consider the effects of a hangover. Eight hours from "bottle to throttle" does not mean you are in the best physical condition to fly, or that your blood alcohol concentration is below the legal limits.
4. Recognize the hazards of combining alcohol consumption and flying.
5. Use good judgment. Your life and the lives of your passengers are at risk if you drink and fly.
Some of the effects of various blood alcohol concentrations
0.01 - 0.05% (10-50 mg%) average individual appears normal
0.03 - 0.12% (30-120 mg%) mild euphoria, talkativeness, decreased inhibitions, decreased attention, impaired judgment, increased reaction time
0.09 - 0.25% (90-250 mg%) emotional instability, loss of critical judgment, impairment of memory and comprehension, decreased sensory response, mild muscular incoordination
0.18 - 0.30% (180 - 300 mg%) confusion, dizziness, exaggerated emotions (anger, fear, grief) impaired visual perception, decreased pain sensation, impaired balance, staggering gait, slurred speech, moderate muscular incoordination
0.27 - 0.40% (270 - 400 mg%) apathy, impaired consiousness, stupor, significantly decreased response to stimulation, severe muscular incoordination, inability to stand or walk, vomiting, incontinence of urine and feces
0.35 - 0.50% (350-500mg%) unconsiousness depressed or abolished reflexes, abnormal body temperature coma; possible death from respiratory paralysis (450 mg% or above)
* Legal limit for motor vehicle operation in most provinces is .08 or.10c/c (80-100 mg of alcohol per ml of blood).
Reprinted from: Medical Facts for Pilots Publication AM-400-94/2 FAA Civil Aeromedical Institute Aeromedical Education Division AAM-400, P.O. Box 25089 Oklahoma City, Oklahoma 73125
CAFFEINE AND FLYING "TO CAFF OR NOT TO CAFF?" Is That the
Question? (c)
[Reprinted with the kind permission of the Aviation Safety Institute]
[Edited for Safety FAQ]
By Lt. Tom Pokorski, MSC (Ed: This article is borrowed from the Navy Safety Center publication called APPROACH, May 1985, Page 10 to 11.)
Caffeine is a chemical naturally found in several plants that has for centuries been consumed for its stimulant properties. For any chemistry buffs out there, it is a member of the methylxanthine family. In its pure form, it is a white, bitter-tasting crystal. Like many other substances used by our society today, caffeine used moderately(about 200 to 300 mg per day) should have no detrimental efect on MOST people. I stress MOST because individuals with certain medical conditions should use no caffeine at all. Excessive caffeine consumption, however, can cause problems for almost everyone.
The lethal dose for caffeine is 10,000 milligrams, and you won't reach that level unless you're drinking over 70 cups of strong coffee at one sitting. However, many detrimental effects can be observed at much lower levels of intake. Probably the best-known effect that caffeine causes is that of a stimulant. The person who jokingly says, "I just can't function in the morning until I've had my first cup of coffee" probably sums it up the best. Many overconsumers of caffeine can actually develop a physical need for the drug and will exhibit certain withdrawal-like symptoms if they go without any for a few days. This stimulant effect is not always bad. If used properly and at the right time, the effect can help give you the alertness you might need in a tight situation. However, like any stimulant, the "up" period will always be followed by a certain "down" phase when your body has used all the caffeine in the system. Loss of sleep is another problem which often haunts caffeine abusers. Caffeine causes the stomach to increase acid secretions which on an empty stomach can be particularly distressing. It is also a diuretic which, in layman's terms, simply means that the old urine tank reaches the full level faster than it normally would. This can be a big problem on longer flights in some aircraft.
Interestly, studies have shown that caffeine increases the free fatty acid level in the bloodstream. "So what?" you may ask. Some endurance runners think this can be very beneficial for extra energy toward the end of a race. So if you see some runners drinking small amounts of coffee before a race, you know why.
All the stresses caused by caffeine are problems one would probably function much better without, especially when working in an already high-stress occupation such as aviation.
As stated earlier, caffeine is found naturally in a number of plants. Although it can be produced artifically in a laboratory, most of the caffeine marketed is derived from those plants. The coffee bean is probably the first thing that comes to mind, but caffeine is found in various tea leaves and in the kola nut. Table 1 lists some of the more common products that contain caffeine. Since every study differs to some degree on exactly how much caffeine is in each product, I've listed an average taken from several sources.
How Much Caffeine?
| Item | Milligrams of Caffeine |
| Percolated coffee (5 oz) Regular brewed | 90-120 (depends on strength) |
| Drip coffee (5 oz) Regular brewed | 100-150 |
| Instant coffee (5 oz) Regular brewed | 50-90 |
| Decaf brewed coffee (5 oz) Regular brewed | 4 |
| Decaf instant coffee (5 oz) Regular brewed | 2 |
| Tea (5 oz) brewed/instant | 20-80 (depends on strength) |
| Coca Cola | 39 |
| Dr. Pepper | 46 |
| Ginger Ale | 0 |
| Mountain Dew | 51 |
| Pepsi-Cola | 36 |
| 7-Up | 0 |
| Sunkist Orange | 0 |
| Water | 0 |
| Orange juice | 0 |
| MOST herbal teas | 0 |
| Cocoa beverage (6 oz) | 10 |
| Milk chocolate | 6 |
| Excedrin | 64.8 |
| Vanquish | 33.0 |
| Empirin compound | 32.2 |
So, what does this all mean? What can you do to prevent caffeine from being a problem? As stated before, most experts tend to agree that less than about 300 mgs of caffeine per day should not be hazardous, for MOST people. But, YOU must decide what is good for YOU. There are ways to control your caffeine intake. First though, you need to know how much you are using. Do this by making a table similar to Table 1 for a typical day. If you decide that the amount is excessive and want to reduce it, here are some guidelines for you. If you drink coffee, decide how many cups you can drink and keep count each day. If you make your own coffee, remember the stronger the brew, the more caffeine.
Decaffeinated coffees are becoming more and more popular nowadays; however, they can cause problems of their own. Most decaffeinating processes use a solvent (trichloroethylene or methylene chloride, among others) to extract the caffeine. These processes can add to or change the other organic compounds in coffee. Another process which seems safer in Switzerland, using steam only for extraction. This process, however, is more expensive and the coffee is normally sold only in gourmet stores.
All the caffeine extracted goes into medications or soft drinks that don't originally have caffeine. That's right, a lot of the caffeine in soft drinks is added. So again, if you're looking to reduce your caffeine consumption, watch what kind of sodas you drink. There are a lot of drinks on the market now that contain little or no caffeine.
Probably the best way to cut caffeine intake is to drink something which is naturally caffeine-free. Water is great, but people tend to get bored with it. Most fruit juices are also excellent. Many teas are on the market with ingredients containing no caffeine.
As I mentioned before, quitting caffeine will cause withdrawal symptoms. These symptoms often persist for two or three weeks after the last caffeine intake. They range from drowsiness and irritability to severe headaches. Also reported have been fever, chills, nausea, depression and many others. Many people will treat these symptoms with over-the-counter pain medications which normally will be of no help. However, the extra-strength does usually contain caffeine and obviously will help somewhat by satisfying the craving. For heavy caffeine users, the symptoms can be quite severe, indicating a real need to stop. These people should see their flight surgeons for assistance in stopping. For these individuals, after they've controlled their caffeine use and the symptoms have passed, they will find they'll enjoy a better quality of life.
So if you're trying to answer the question "To caff or not to caff?" stop and think of these few things and make the decision that is right for you.
(Lt. Pokorski is the aviation medical safety officer for Training Air Wing 6, NAS Pensacola, FL.)
ED: The author failed to make more than a passing comment about the diuretic effects of caffeine. It is generally accepted amongest the civil flight surgeon community that consumption of one cup of coffee with caffeine results in excretion of slightly more than one cup of urine. If the person fails to compensate for the extra loss of body fluid, there will ultimately be a reduction in brain fluids which are so very essential to proper cerebral functions. Thus, the knowledgeable flight crews who have either learned the lesson or heeded the warnings will consume sufficient non-caffeine liquids to preserve the proper body fluid level.
EATING BEFORE FLYING
(This information is excerpted from "Aviation Safety" [Feb 1/96]. Since
"AS" is copyrighted, I could not directly reproduce the article.)
Does eating before a flight increase or decrease your chances of becoming airsick? It seems to vary from person to person and between the sexes, but for many people an appropriate light meal seems to help. However, there is evidence which suggests that one should not eat immediately before the flight. Research published by the University of North Dakota Center for Aerospace Sciences produced mixed results. Studies showed that women were more likely to become airsick if they ate less than six hours before the flight. (The AS article did not comment on the equivalent male results.)
A number of studies, include the North Dakota study indicated that heavy foods, salty foods, diary products and high protein diets result in an increased risk of airsickness. It would seem that vegetables and complex carbohydrate diets run the lowest risk of producing airsickness. Additionally, males reduced their chances of airsickness if they ate only three or fewer meals a day rather than continual snacking. (The AS article did not comment on the equivalent female results.) Reducing total caloric intake also reduces the risk of airsickness. (It is not clear in the AS article if that trend held for both males and females, or just males.)
It is not wise to avoid food before the flight because then the blood sugar levels might be too low at flight time. Compounding this is the fact that most people drink fluids only during a meal. Therefore, if a meal is avoided, chances are the person is slightly dehydrated as well. Neither a low blood sugar level or dehydrated condition is good for flying! Conversely, a large meal eaten just before the flight can reduce pilot performance because large amounts of blood will then be routed to the gut for digestion.
In any case, the diet suggestions listed above are healthy!
FUEL FOR THOUGHT
- Poor nutrition can turn a pilot into a sick,
confused passenger. Here's how to "refuel" properly.
(This information is excerpted from "Aviation Safety" [March 1/96]. Since
"AS" is copyrighted, I could not directly reproduce the entire article.)
Apparently the human fuel requirement is probably the most frequently overlooked element in good pilot preflight panning.
"Food converted into glucose is the only source of energy for the brain. [ref 1] Neither the brain nor the central nervous system can store blood sugar and, thus, require constant refueling. [ref 2] Physiological responses to a lack of sufficient glucose include fatigue, mental confusion, faintness, headache, forgetfulness, dizziness, blurred vision, coldness in the extremities, low blood pressure, nervousness, depression and, of course, extreme hunger."
Hypoglycemia is not a rare disease which affects only a few. Most people will become hypoglycemic five hours after the last balanced meal. Fasting for 10 hours is almost guaranteed to impair a pilot's mental, physical and perceptive abilities. Therefore, if breakfast is not eaten after a night's sleep you will be in a condition called "fasting hypoglycemia".
A balanced diet is the best defense against hypoglycemia. Such a balanced diet will also provide the neuronutrients which assist in mental functioning and the proteins and fats containing essential vitamins, nutrients and minerals recommended by the FAA Civil Aeromedical Institute. Neuronutrients are vitamins and minerals that are chemically converted into neurotransmitters. Neuronutrients are required for regulating body temperature and metabolism as well. For example, chromium, which is found in whole-grain cereals, bran, and wheat germ, poultry, beef and broccoli stabilizes the burning of sugar for energy. Eggs, fish and whole wheat also provide the B vitamins which are necessary for proper mental functioning. The latest research suggests that a larger than normal dietary dose of neurotransmitters can actually enhance mental functioning and improve memory. These neurotransmitters, like zinc and iron, can be found in fish, meat and leafy green vegetables.
High sugar intake diets comprising of refined sugar and white flour are bad for you because they cause the pancreas to secrete excessive amounts of insulin, a hormone which causes the body to burn sugar. [ref 2] Consequently sugar levels will drop to low levels and starve the brain. In addition, the consumption of alcohol, caffeine and nicotine compound the problem.
The article suggests that the "I'M SAFE (Illness, Medication, Stress, Alcohol, Fatigue, Emotion) personal preflight acronym checklist become I'M SAFER (R = Re-energize, Refuel or Revitalize) in recognition of the importance of proper nutrition.
If you find that you frequently suffer the symptoms of hypoglycemia you might want to have a glucose tolerance test.
So next time you go flying, remember to eat a proper meal before the flight, and carry some water and nutritious snacks for the flight.
REFERENCES
1) Michael LaCombe, MD "Medicine Made Clear," 1989, Diringo Books, Woodstock, Maine
2) Maura Zack, Wilber Currier, MD, "Sugar Isn't Always Sweet," 1983, Uplift Books, Brea, CA.
Many safety devices and procedures that are developed for air carriers and commercial aviation are resisted by other general aviation pilots because of the expected increase in operating costs. However, there is one procedure practised by large operators that private pilots might consider adopting, since it costs nothing more than a little time--and in the long run could save both lives and money.
That practice is the postflight inspection. Preflight inspections are a time-honoured and widely accepted procedure, directly tied to the Federal Aviation Regulations that make the pilot responsible for not taking off in an aircraft unless it is airworthy. But many people in aviation feel that mechanical deficiencies which arise during a flight can best be identified and attended to at the completion of the flight, rather than before takeoff.
To some extent this reasoning is psychological. The pilot who is eager to be airborne is looking ahead in thought, which may reduce the acuity of one's near vision. Unconsciously you may overlook items which on closer inspection might call for immediate maintenance work. You may have invested considerable time in weather briefing and flight planning; and you hate to disappoint passengers or friends you expect to meet at your destination. You are, in a phrase, "departure-oriented."
This is in sharp contrast to the frame of mind of the pilot conducting a postflight checkup at the destination airport, when all of the pressures of being a pilot-in-command are over for the moment. You tend to relax, when you finally shut down the engine and fasten the tie-downs, basking in a glow of satisfaction at having completed another flight safely and effectively. You may feel a sense of gratitude toward the faithful "old bird" that has carried you swiftly and obediently through hostile elements of the environment.
This is an ideal moment to take a slow walk around to see how your faithful old bird has faired en route. You are not looking for anything as obvious as arrow shafts or bullet holes (not usually) but more subtle signs of strain or wear, such as the following:
Wrinkled skin. Could indicate internal structural damage, following exposure to severe turbulence or airspeeds in excess of limitations for a given manoeuvre. Require immediate examination by an appropriately qualified technician.
Metal damage from stones or other debris. Propellers are especially vulnerable, also the underside of the fuselage and the airfoils.
Mud, ice, etc. clogging up small opening, such as pitot tubes or vent holes, may give you distorted readings on vacuum pressure instruments.
Scuffed or torn tire surfaces. Can occur even on paved runways, as a result of potholes or metal parts dislodged from aircraft.
Uneven landing gear extension. Could be caused by loss of tire pressure, improper pressure in struts, leaks, etc.
Fuel stains, or other signs of leakage of fuel, oil, or hydraulic fluid. The source of a leak should be found and corrected by a qualified mechanic prior to further operation of the aircraft.
Your experience during the flight may direct your attention to other potential trouble areas. Excessive fuel consumption en route? Check the fuel caps seating, the fuel drains, underneath tanks and line fittings. High oil consumption? Look for drips around engine seals. Uneven braking or steering on the ground. Take a good look at the undercarriage. And so on.
After any long cross country flight the chances are good that you will find at least some minor problems if you conduct a postflight examination while the flight experience is still fresh in your mind. The chances are equally good that if you just "let it go for later" you will forget about whatever concerned you during the flight. You may have urgent business in town, but that is hardly ever so pressing as to justify not putting together a squawk list before you leave the aircraft. The time you take to do so could save you hours or days of delay the next time you get ready to fly the aircraft. It might also save your life.
This is not to suggest that a postflight inspection should take the place of a pre-flight inspection--both are important. There are special problems which occur typically during periods of disuse. Corrosion or rot may develop. Insects or rodents may nest in engine tubing. Water may condense in the fuel. Tire pressure may go down. Inspections may become overdue. And so forth.
Problems surfacing during preflight could be said to be more of a passive nature than those which may be found immediately after a flight. Both are important.
A pilot's mental condition or attitude is just as important a preflight item as the aircraft, engine, parachutes, etc. A pilot's actions can be completely altered by various attitude changes, such as: daydreaming, family trouble, money trouble, desire to show off, overconfidence, under confidence, vexations - many others. We cannot eliminate family troubles, money troubles. They are part of life. We don't want to eliminate completely the desire to show off, for without it, there would be no aerobatics, airshow, or competition. There will always be times when we are depressed, others when we're just mad at someone, so we must be aware of the fact that they do exist, they change from hour to hour, and that
we must compensate for them as we must compensate for a crosswind.
To have the ability to accurately and honestly appraise one's own mental attitude, allow for a margin of error in his appraisal and then take just reasonable steps to cause this attitude to help, rather than hurt him should be the goal of every pilot. He should then, prize this possession and regularly
preflight it as the most important part of his safety equipment.
YOU AND YOUR "ENVELOPE" (c)
[Reprinted with the kind permission of the Aviation Safety Institute]
Edited for Safety FAQ
By Lcdr. John Wilckens, MC, USN VP-17
(Editor's Note: Commander Wilckens has done a masterful job of describing to Navy flight personnel some of the important facets of their aviation lives. We present this article taken from APPROACH Magazine, May 1984 issue, published by the U.S. Navy Safety Center at NAS Norfolk, VA. Our thanks to NAVSAFECENTER for the priviledge of reprinting Dr. Wilckens' fine work.)
From the title you are probably expecting some technical article updating existing ejection parameters of your aircraft. Instead, this article will discuss YOUR "envelope", the safe operating limits of YOU, the naval aviator. More specifically, I would like to discuss one determinant of that envelope - stress.
Yes, aviators know and handle stress better than most, but you also see a lot more stress. That stress pushes you to the edge of that envelope. That's okay, too. Stress motivates life and nature in the evolution process. Stress is adaptive, the vital force that heightens our response to meet any challenge.
But modern society has evolved through technology to pose a whole new dimension of stress which we are just beginning to understand. The stress response, that rush you feel on final approach, prepares us for the "fight or flight" syndrome which allows you to bring the aircraft aboard in the worst circumstances. That same stress response is working when the skipper calls you in on the carpet about Petty Officer Jone and his fifth rubber check. "Fight or flight" - who are you going to fight? Or, where are you going to run?
If stress continues for a period of time, it can fatigue you and later damage the body to the point of disease or disfunction. You can feel the "hunkydory", flying on top of the world, and be in a state of dysfunction. To make things worse, the closer you are to that point, the less aware of it you are. It's this point, the envelope, we should concern ourselves with.
Stress is a well-described physiologic process. It directly involves the brain, the autonomic and central nervous systems and the endocrine system.
The brain is a very complex organ, but for simplicity let's consider three separate parts of it. The brain stem, the most primitive part of the brain, is concerned with our basic self-preservation. As we moved up the "evolutionary" ladder, we developed the limbic system. It refines basic instincts. As man, we developed a third part of the brain, the cortex. This is where we think and act. It compromises the majority of our conscious thought.
Physiologically, our body has not kept pace with our mind's development. The stress response, engineered for our brainstem concerns, is triggered also by our limbic system and cortex. So while the response was designed for action, it's often triggered when action is not required.
Okay, so we trigger the stress response - what happens then? The stressor, the threat (again, real or imagined) is received through stimulation of one of our many sensory pathways, i.e., we see a fire warning light. A lot of filtering and circuiting is done in the brain. That red light, through your training, puts you at physiological "general quarters". Your hypothalamus becomes stimulated which next triggers the pituitary gland. The pituitary gland secretes Adrenal Cortistraphic Hormone (ACTH), which circulates in the blood and stimulates our adrenal glands. Once in the adrenals, the ACTH stimulates the production of cortisol, aldosterone and epinerphrine, commonly thought of as the stress hormones.
Cortisol prepares for increased energy with its effect on metabolism. Blood sugar, the fuel for the stress response, increases. A snapshot of the body's and blood's chemistry at the height of stress response would resemble the clinical condition, diabetes. The short term effects of cortisol provide a lot of energy to meet a particular demand. Prolonged cortisol stimulation had many effects that are not so beneficial.
Aldostreone stimulates that kidneys to hang on to sodium. This has the effect of increasing the circulating blood volume, increasing blood pressure and increasing stroke volume - the heart pumps more blood. Again, in the short term, this is a beneficial response. The long term aldosterone effect is hypertension with its attendant complications.
The circulating epinephrine, or adrenaline, potentiates the above effects. Along with the triggerd sympathetic autonomic nervous system, cardiac output increases. There is increased excitability of the nervous system and increased metabolism.
All these things help put you at alert to handle some stress demand. Using the fire warning light again, the stress response speeds up your metabolism and your ability to work through the emergency. You're thinking quickly, going through the checklists, with your hands swiftly enacting the steps. Your visual acuity sharpens; your reaction time quickens, and you become more sensitive to your aircraft's performance. Through training, stressful training, your body has channeled the generalized stress response to effect a positive controlled execution of procedures to handle an emergency.
Most of you have noticed that if you stay ahead of the aircraft and execute your mission to the standards expected, you are exhausted after a flight. That is the effect of the stress response as it moves from the "alarm stage" to the stage of "adaptation". Some of you adapt well and the stress demand lessens. But physiologically, the response is going on regardless of how you feel. Even in positive control and ahead of the aircraft, you are stressed. As the body and its systems approach exhaustion, the stress response becomes maladaptive.
We have all experienced these prolonged stress symptoms but do we appreciate the toll they take on the body? Ninety percent of all hypertension has "no specific cause" and is labeled essential hypertension. Hypertension, regardless of the source, is a major risk factor for heart disease. More subtly, the prolonged stress response affects the body's natural immune or self-defense system. The immune system is not a target organ of the stress response per se. The prolonged stress response marches on at the expense of the immune system, making us more susceptible to all kinds of diseases, both infectious and noninfectious. A body not only has to be exposed, it also needs to be susceptible to become infected by some "bug".
You may all say "well and good", or "that's interesting", "But what does that do for me?" Flying is stressful, and you do a good job with it. The stress of flying you feel confortable with, but what about all those other stresses? "What stresses?" Well, there are lots. They are subtle. They are insidious. they are accumulative. And physiologically, they are dangerous.
So what are these other stresses? There are psychosocial stresses, bioecological stresses, and the stresses of our own behavior and personality. Keep in mind they trigger all those hormones and systems the same as the fire warning light. Let's look at some of the psychosocial stresses:
Two big ones are PCS orders and deployments. these changes are stressful, triggering the stress response, even if those orders are your first choice or the deployments is a "liberty run". Remember, any change is stressful.
Then, there is frustration. How many times are you tasked with more than is reasonable? Sometimes it seems like the whole U.S. Navy is meeting commitments that exceed its capability. That's not without a price. Frustration triggers the stress response and can overload you.
Personality and behavior patterns are stress-related. That agressive, dominating personality you are so proud of can go a little too far, emerging as hostilty. Rigid and unbending profiles will trigger the stress response when you find yourself between the proverbial "rock and a hard place". Another typical stress provoking personality trait you may exhibit is you obsessive compulsiveness and your attention to detail. For the most part, that perfectionism keeps you alive and allows you to overachieve. Just realize that physiologically it can be triggering the stress response. To a point it is adaptive, but past that point it is maladaptive.
Some of the last stresses I want to discuss are bioecological. Some may seem obvious, but few are really appreciated. How about noise? Those 120 dB on the flight deck or 85 dB in your office at the hangar trigger a stress response. In your office, you close the window to close out noise only to experience another, heat. Dehydration and fatigue are all stresses in their own right. If your environment is not comfortable, it is stressful.
Another factor we ignore, usually because we don't understand it, is biological rhythms. We are aware of circadian rhythms, our 24-hour biological clock. Aviators have to cross time zones and fly at night. You can't change that, but keep a mental note you are triggering a physiological response.
While aviators do well with stress, nutritionists and physiologists would wonder how, because of your "stress prone diet". Starved and hypoglycemic, you show up for your brief with a "fighter pilot's breakfast", coffee and a candy bar. It provides instant energy until your pancreas squeezes out healthy amounts of insulin. That insulin pushes most of that sugar into your starving cells causing rebound hypoglycemia. Hypoglycemia produces a stress response. The coffee can also be a problem. Caffeine is a stimulant, acts as a sympathomimetic. It kind of triggers a stress response without even a stressor. One, two, maybe three cups a morning are fine (six-ounce cups); any more is unhealthy and counterproductive.
If breakfast is bad, lunch and or dinner are probably worse. All that processed food has little nutritional content, is high in salt and has tons of fat. Only when you drag that burger through the garden do you get any compensation. What you eat and drink is important.
If that's not enough, some of you tend to add insult to injury with a smoke or a chew, or whatever. Tobacco nicotine also ignites a stress response.
The psychosocial, bioecological and personality stress can be very insidious. The stress response is generally the same, regardless of the trigger. The stress response was designed for action, not for writing evals, passing an NTPI or driving to work. It was designed for night hovers over an overboard sailor in sea state 5, fire warning lights and combat. Cortisol, enephrine and aldosterone don't help family fights, command selection boards or flat tires.
Many of you are probably thinking you have got it all "compartmentalized". "That's how I can live in this stressed and insane world and still fly". Compartmentalization is protective and certainly explains how you can leave the XO, wife, car and kids on the deck while you fly. I feel it's a rather new evolutionary tool. To a point it short circuits cerebral thoughts and stressors, shelving them for a more opportune time. But it's short term, too. Like stress, it can be adaptive if used as designed and maladaptive if used in a prolonged sense. Your brain has only so many shelves, and it can get overloaded. Also, you can't compartmentalize something forever. That stuff has to surface some time and needs to be dealt with. Pushing problems continually under conscious thought becomes stressful in itself.
So what now? Well, half the battle is won. Knowing you're close to the edge of the envelope and how you got there is important. You may not be able to change that. You may not want to change that. But you also want to know when you're over, what got you there, and how to get back in the envelope.
As aviators, you understand systems. You are sensitive to system malfunctions. Popped circuit breakers, vibrations or annunciator panel lights trigger a dissection of the system involved trying to figure out the particular malfunction. You appreciate indications of impending engine failure long before the engine actually fails. In fact, you shut the engine down before it fails. You need that same sensitivy about your own biological systems. Appreciate the ping or vibration in your own body. Don't ignore headaches, low back pain or eye strain. Don't discount high blood pressure readings, allergy flare-ups or recurrent illnesses. Your GI system bears particular attention. Your body deserves the same careful appreciation as your aircraft.
If we insist on pushing our bodies like machines, we need to treat them with similar care. Schedule maintenance, do preventive work or perform corrosion control. After so many hours the aircraft and engines are inspected, put into phase, go to NARF, etc. Take leave. You shouldn't be flying if you haven't taken leave in over a year. If you work hard, play hard. But that play should not reinforce the stress response, it should release it. On occasion you need something mindless and non-ego-serving. You should come off the golf course more relaxed than when you went on it; if not, you need a new sport.
Identify the stressors. You can't always change them, but there may be alternatives. Much of our stress is mental or psychological. Is it necessary? Are things prioritized in your life? The big picture helps. Goals help. A spiritual experience may help. Look at your day. Could it use a little more structure and management? Does everything have to be done by crisis management? If you're spending long hours at work, there's a good chance things aren't organized, running efficiently, or you're doing somebody else's work. Delegate responsibility. Learn to say no. Don't over-commit yourself. Take your horrendous workload and divide it into several manageable parts. Set goals, plot progress, document work. Try avoiding all other unnecessary stress. Accept help, accept fallibility. Plan ahead, anticipate and realize vulnerabilities. A big misconception is that boredom is relaxation, but it is not. It happens to be very stressful. Vacation and leave doesn't always mean relaxation either, with taxis, airports, lost travelers checks, etc. And you diet. Do your diet justice. Make every effort to modify it to some healthy standard. You put "high-test" in your aircraft and your sportscar. Why not put some good "fuel" into your own body's engine?
Another myth is that alcohol relieves stress. When you come home each night, before you kiss the wife or kick the dog, how many of you grab for a beer from the fridge? Somehow that first beer puts things into perspective. If one does it for you - great. But if it takes many more, you've got a problem! Alcohol is a chemical depressant. In small amounts it acts like a stimulant because it depresses the restraining neurotransmissions. In larger amounts it depresses the brain in general, including those stress response activators.
Alcohol doesn't make problems go away. If you thought you had brushfires before, DWI or an alcohol-related incident will certainly complicate you life more. Physiologically, alcohol inhibits other systems, the immune system in particular, which is already under attack from your stress. Your gastrointestinal system, to include the liver, is tested. Long after your blood alcohol level returns to zero from an overindulgence, your brain suffers from lost neurons and neurotransmitters. In the final analysis, if not a stress itself, alcohol interferes with your body's abilities to handle stress. It certainly is not a remedy.
What is a good prescription for stress? One of the best is exercise, aerobic exercise in particular. Yes, exercise is a stress, but it's used as designed, mobilization for action with action. A good aerobic routine makes the body systems more efficient. Excess fat and sugar are burned as fuel. The body changes its metabolism and attempts to realign itself with natural cues. Sleep becomes better, if not more. Diet becomes healthy. Excess stress metabolites are burned off, allowing the body as a whole to rest and recuperate after exercise. You gradually obtain the physical and mental ability to do more work in less time.
But exercise is not a panacea. Again, it's also a stress, and to extremes it can precipitate failure in the body. As your percent body fat drops way off, your immune system suffers. World class athletes are intimately aware of this. They train to peak for the big event. If they peak too early, they experience illness or injury at game time. After the big event, athletes reduce or stop training for a period of time to recover. This is sort of a "safety standdown" for the body. As aviators, you don't peak as a rule. On deployment or with a max flap, you may extend yourself more. But day-in day-out, you operate just below peak performance. You call on the reserves when that emergency happens. Exercise then should enlarge your envelope, not bring you closer to the edge of it. Exercise should not stimulate psychosocial stress either. It's natural for aviators to be competitive when they put on a jock strap. But if you're breaking tennis rackets after you lose, you're missing the point. Personal records and goals are great, they encourage better performance and make exercise more fun. They are not essential though. Don't be obsessed with them.
For you, the best way to get that aerobic exercise is to run. For a unit of time, it's the easiest and quickest way to get in shape. The gauge formula for exercise is: subtract your age from 220, multiply that by 0.75. That's your target heart rate for exercise. Do that 30 to 40 minutes at least every other day. More is better but be careful and listen to your body Alternate hard and easy workouts. Alternate exercises if possible. If you begin to feel rundown, skip a day or two.
Why should you listen to all this stress stuff? Two good reasons are money and fitness reports. First, fitness reports. Again, what has your Navy training been geared to? Stress? Actually it's stress management or recognizing and handling stress. As your career progresses, so does the stress. The higher you go, the keener the competition, almost so as to keep pace with the accompanying stress. If you aspire to a Navy career, command or flag, be fair to your abilities and intelligence. Learn your envelope. Operate it to your benefit.
Understanding and managing your stress profile also means dollars. The obvious dollar sign is the broken airplane. You notice also it's the talented or good pilot or crew who crash. There are a lot of reasons for this. One is that the good aviator is stressed a little more than the average stick. His talent got him a great, but demanding, ground job, an instructor qualificatio and all the headaches that no one else can handle. In perspective, that means success, a top one percent FITREP. Out of control that can spell disaster.
Besides the cost of your airplane, there's the cost of you and your crew. A seasoned aviator is worth more than his airplane. And the higher up you go, the bigger the hole you leave when you go. Also, the higher up you go, the more subtle your demise from stress. Breaking airplanes, you finally begin to realize the end organ damage of the chronic stress response. Heart attacks, strokes, diabetes and alcoholism. The Navy is just beginning to realize its investment in you and is beginning to protect that investment. Large corporations are putting their executives through stress seminars. They are forcing physical fitness as an adjunct. They've noticed not only fewer six digit executive holes to fill but that productivity has increased. As a two ocean Navy covering three oceans, we should follow suit.
As aviators and as officers, stress is real and it's physiologic. You can't ignore it. Understanding it and then managing it is the key. You, the person, have a safe operating envelope. It's not as well described, but it is just as finite as your aircraft's. You don't fly your aircraft intentionally out of its envelope. It logically follows you should stay within yours. The 17th century philosopher Blaise Pascal wasn't an aviator, but he says something profound to each of us: "The greatness of the human soul is shown by knowing how to keep within proper bounds".
PROTECTING YOURSELF FROM ULTRAVIOLET RADTION
from the internet
I have done extensive research into the UV absorbtion properties of various materials. The results of that research are sumarized in an article appearing in Soaring Magazine, "Soaring Radiation Hazard" June 1991, pp29-32, in Sport Aviation, July 1992 pp36-38 and also in a recent copy of the SAAA (Sport Aviation Association of Australia) Magazine.
My research consisted of, but wasn't limited to, analyzing material samples in a Spectrophotometer to get a plot of their % transmittance vs wavelength. I obtained data on various types of Plexiglas and window glass and also numerous UV protection films. I also took data on samples of sailplane canopy plexiglas, both tinted and clear, from production canopies.
First some background on UV. Ultra-violet radiation (UV) is categorized by its wavelength into UVB (280-320nm) and UVA (320-400nm). UVB is the primary cause of sunburn. However, there is extensive medical evidence that BOTH UVA and UVB cause skin cancer. UVA is worse than UVB in some ways because it penetrates deeper into your skin than UVB. UVA is also associated with skin wrinkling and sagging.
The research data showed that both Plexiglas and plain window glass block most, if not all, UVB. That is why you don't sunburn as quickly, if at all, through your canopy or car windows. However, neither Plexiglas nor window glass provide any protection against UVA. This can be particularly bad for soaring pilots since the UVB burning rays are blocked by the canopy, one tends to stay out longer thus being exposed to large amounts of UVA. Even the tinted Plexiglas provided no additional UV protection.
Sunscreens have the same problem. Most all provide adequate protection against UVB, but very few provide any protection against UVA. Indeed, the SPF factor only applies to UVB, it gives no information about the UVA blocking abilities. Only those sunscreens which state that they are "broad spectrum" offer any signifigant UVA protection.
With regard to eyeglasses, what you want is an eyeglass which states that all UV up to 400nm is blocked. They typically say UV400 somewhere on them. Most all high quality glasses have it. Beware of cheap sunglasses which just claim to "block UV rays". You don't know what you are are getting.
So how does one protect oneself from UV?
1) Use a "broad spectrum" sunscreen. The operative word here is "use". Sunscreens can't help you unless you use them and reapply them often.
2) Get a good hat and keep it on. The typical American Baseball hat provides little UV protection. While it protects your nose and forehead, it does nothing for your ears, cheeks, and neck... THE MOST COMMON AREAS FOR SKIN CANCERS TO FORM!!!! Wear only a baseball hat and you are at risk of skin cancer in those areas. Instead wear a broad brimmed hat like a cowboy hat or a pith helmet
Don't even think about flying without a hat. The typical tennis hat is probably best because it protects ears neck and face, but doesn't restrict visibility.
3) Various window films are available for cars which block both UVA and UVB. It is not necesscary to apply a dark tinted film, some very effective films are clear. I have experimented with applying films to glider canopies, but those experiments were of limited sucess. I would not recommend it.
4) Wear as much clothing as possible. Long sleeved shirts and pants do a good job keeping the sun off.
In closing, let me quote from my article:
It is imperative that we protect ourselves from UV on a daily basis throughout our lives. By starting now, one stands a good chance of avoiding the skin cancer surgery that many long time soaring pilots are now requiring.
Edited for Safety FAQ
A great deal of what is written on human factors is written by academics in scholarly journals, and rarely receives wide distribution among "working class" pilots. Many of the essays are written for the psychological community in an abstract, sometimes tedious, style that seems reluctant to "cut to the chase". The bottom line on many human factors studies seems to be that there is no bottom line. A body of academic literature on pilot performance is growing quickly, but is not having much influence in the daily rough and tumble of aviation.
There is encouragement in a new book called Flightdeck Performance - The Human Factor, by David O'Hare and Stanley Roscoe, with contributions by Gordon Vette and Michael Young. Unlike many aviation-safety and human factors books, this one is readable by pilots, because it delivers a very good mixture of theoretical information and practical analysis. The book is divided into four sections. In section one, the authors examine the physical senses, providing what is probably the best summary available outside a medical textbook.
Sections two, three and four look respectively at flight training and aircraft cockpit/simulator design; the challenges of navigation and communication and the impact of stress and fatigue; and pilot judgement and social psychology in the cockpit. Flightdeck Performance is not a large book, but it covers a lot of territory, presents quite a bit of new information, and is supported by excellent footnoting and bibliography.
Authors O'Hare and Roscoe indicate that pilots are tested for near and far vision using eye charts, but there is not test for what is called "dark focus" - the resting state of the eye when it has nothing on which to focus, as, for example. when the pilot is staring into the darkness. Apparently our dark focus varies from person to person, but changes with age.
Young people with normal vision have a dark focus at about arm's length. As we age, the point of rest for our eyes moves outward, as with near and far vision, particularly after age 40 to 45. Older pilots with a distant dark focus may have greater difficulty than average with "black hole" approaches to brightly-lit landing surfaces. The perception is that the runway is large and the threshold lower than it really is, and a pilot amy fly the aircraft into the undershoot area to compensate for this illusion.
The dark focus, according to O'Hare and Roscoe, plays a part in accidents involving aircraft with head-up displays (HUD). Head-up displays in military fighter aircraft are images projected on the forward windscreen or a glass plate. In theory, the illuminated numbers, lines and symbols are collimated with infinity. Therefore, a pilot should not have to change his or her focus to see the outside world and the head-up display data in the glass of the forward windscreen.
But tests in ten subjects showed that, looking through a HUD, the subjects shifted their focus inward in varying degrees, closely correlated with the individual's dark focus. Although this phenomenon may be undetectable to the individual, it causes terrain features to appear farther away and closer to the horizon than they really are. This can result in delayed pull-ups in dives or a high roundout in landing.
Sleep disruption and fatigue are discussed at length, and the authors cite a study done by the CAA (Civil Aviation Authority) in England which suggests that sleep deprivation and fatigue result in different errors of performance.
When tired due to a lack of sleep, a pilot tends to make a rare, but gross error in aircraft handling. However, when a pilot is bored and complacent due to flight frequency, motivation to fly with fine accuracy will be reduced, and errors in handling will be accepted. Studies have also revealed that high repetition in takeoffs and landings (the typical short haul operation) carries over after the day's work in higher stress-hormone levels in pilots., and this increase can be measured by researchers.
Long-haul operations take their greatest toll when the fatigue of a long duty day coincides with the low point ion circadian cycle. Laboratory testing of candidates suffering fatigue and circadian low cycle shows a performance decrease as large as 35%.
As O'Hare and Roscoe conclude:
"...the rare occurrences of accidents do not result from the operation of unusual or idiosyncratic processes; they occur mostly as the result of fairly well-understood perceptual, cognitive, and social forces that can be seen in our every day behaviour..."
REFERENCES
David O'Hare and Stanley Roscoe (with contributions by Gordon Vette and Michael Young), Flight Deck Performance - The Human Factor. Iowa State University Press/Ames, 1990. ISBN 0-8138-0161-3.
PSYCHOLOGICAL FACTORS AFFECTING CHECKLIST USE
Asaf Degani and Earl Wiener, from the ICAO Journal
To perceive something is to be conscious of it and to pay attention to it. Perception is a dynamic process. It changes constantly depending on the physical stimuli and on the way in which the brain blends incoming information with information already stored in memory. Therefore, the mere existence of a physical stimulus obtained by a receptor (eg. the eyes) is not an absolute predictor of what the pilot will perceive and act upon while performing a task or checking a list, for example.
When a certain task is performed repetitively in the same manner, operators become experienced with the task. In a sense, they actually create a "mental model" of the task. With experience, the shape of the model becomes more rigid, resulting in faster information processing, the ability to divide attention and, consequently, a reduction in workload. In return, however, this model may adjust or sometimes even override the perception of physical stimuli coming from the receptors and create a bias in the brain (causing one to see what one is accustomed to seeing).
Many of the pilots interviewed by the authors stated that at one time or another they had seen a checklist item in the improper status, yet they perceived it as being in the correct status and replied accordingly. The flap handle, for example, could be positioned at the zero degree slot (physical stimulus), but the pilot may nevertheless perceive that the handle is on the five degree position, and call out "flaps five" because he expects the handle to be there. This incorrect reply is based on numerous similar checks in which the flap handle was always in the proper setting during this stage in the checklist. Often, this phenomenon is coupled with un-favourable psychological and physical conditions such as time pressure, high workload, fatigue, and noise. Nevertheless, the result is a human failure.
Most automobile drivers have had the experience of driving along a familiar route and suddenly realizing that they have travelled some distance without being aware of it. The driver ceases consciously to process information for a significant length of time. As a previous human factors study determined, "the highly practised skill of driving can be controlled by the output of the brains pattern analyzing mechanisms without conscious perception." There was almost a consensus among the pilots interviewed that at many times checklist procedures become an automatic routine (or "sing song," as some called it). The pilot would "run" the checklist, but the reply would be done from memory, and not based on the actual state of the item. The authors believe this is controlled by the output of the brains pattern analyzing mechanism, and that the check procedure is done without conscious perception.
Reversion to older habits is another common phenomenon in aviation, and its extreme usually occurs following a pilots transition from one aircraft to another. This can also affect checklist performance. An example is evident in the 1987 crash of a Jetstream 31 following an aborted takeoff; the flight crew did not advance the RPM levers to 100 percent as called for by the operating procedure and checklist. The captain and first officer had a limited amount of time on the aircraft (47 and 15 hours, respectively), but both had considerable experience in a Beech 99. The operation procedure and checklist of the BE99 require that the RPM levers be set to takeoff position before taxiing. The Jetstream 31 procedure requires that the same levers be set just prior to takeoff. Therefore, the item was the last on the before take-off checklist. The National Transportation Safety Board concluded that under urgency and stress imposed by the controller, the pilots may have reverted back to recent habit patterns and began the takeoff believing that the RPM levers already had been properly positioned.
Another psychological factor that effects checklist performance is the relationship between the speed of performing the checklist and the accuracy of the check. Laboratory research has revealed a very definable relationship between response time and error rate. Therefore, if the pilot scans the appropriate panel(s) rapidly because of time pressure, the accuracy of his perception will suffer and the probability of error will increase.
The relationship between a task and its expected outcome is another factor that affects checklist use. Without the crew witnessing its apparent effectiveness, the redundant function of the checklist can sometimes lead to a decline in the perception of the task's importance. This is somewhat analogous to the use of seatbelts in a car: although most experienced drivers are aware of the consequences of not wearing a seatbelt, the individual's personal experience about the likelihood of an injury while not wearing a seatbelt is relatively low. The same applies to checklist use.
In summary, the combined effect of expectations, experience, and the pattern analyzing mechanism is a double-edged sword. On one hand, this ability makes the user flexible and faster in responding to multiple conditions. On the other hand, it can lead the operator to make a disastrous mistake just because part of the information which was collected quickly or without sufficient attention appeared to match the expected condition.
This article is adapted from the summary of a human factors report which appeared in NASA's Aviation Safety Reporting System monthly safety bulletin. The study also covers social and procedural aspects of checklist performance. A free copy of the study (CR#177549) may be obtained by writing to NASA Ames Research Center, Mail Stop 2624, Moffett Field, CA 94035.
Research on this study began with a focus on checklist typography and design. The research goals changed however, as the authors interviewed airline pilots, observed cockpit procedures from the jumpseat, and studied incident and accident reports. They began to realize that pilots' misuse (or non-use) of the normal checklist could be attributed mainly to other factors. For example, they found that "company culture" (read club safety attitudes) is an important influence on pilot attitudes towards checklist use.
The study tells glider pilots to use a checklist, to take time completing it, and to do more than look at a control and say "open" but to also physically test its movement and observe that, for example, the spoiler is indeed out because if we hurry, our eyes and brains will tell us bare-faced lies.
SKILL FATIGUE
from the CALPA "Pilot"
Skill fatigue, "the deterioration in performance caused by work that demands persistent concentration and a high degree of skill."
Skill fatigue may be combined with or accentuated by other fatigue factors such as sleep loss, and is associated with failure of memory, judgement, integrating ability and presence of mind. The phenomena were first described in 1948 following a classic series of experiments in the UK. Subjects were tested for two hour spells in very high workload piloting tasks demanding sustained concentration and skilled performance throughout the test period, and it was found that skill-fatigued subjects accepted lower standards of performance and safety. With increasing fatigue, integrative ability failed and pilots would chase one instrument at a time, while memory decreased as pilots forgot to monitor side instruments and controls. Performance tended to suffer a vicious cycle of disruption as increased time to observe and interpret instruments lead to greater errors requiring greater control actions which themselves were poorly controlled and required additional correction.
While the incidence of skill fatigue will differ according to workload and the individual pilot, even the most skilled pilot is affected. The observable effects which are apparent to a pilot are one or more of the following:
-loss of accuracy and smoothness of control movements,
-unawareness of the accumulation of rather large errors in attitude,
-an increase in control movements with greater fluctuations to produce a desired effect,
-forgetting side tasks,
-errors of inattention, failure to scan sky, and fixed vision,
-preoccupation with one task to the exclusion of others,
-easily distracted by minor discomforts, aches, noises, etc,
-increased unawareness of performance deficiencies,
-the requirement for larger than normal stimuli to trigger appropriate responses,
-errors in timing,
-overlooking elements of a task series.
The above effects could very well be experienced by soaring pilots, particularly by those on long cross-country flights, in difficult or unusual weather conditions, or during competitions.
Research by psychologist Andrew Smith of the Medical Research Council's Common Cold Unit in Salisbury, England, has shown that a cold or flu can affect your mental and physical capabilities.
Two tests were described. The first test measured the increased reaction time to randomly presented video targets for people suffering the flu and healthy individuals who had two or three alcoholic drinks. People suffering the flu took 57% longer to respond while those who had a few drinks suffered a 5-10% increase in reaction time.
The second test examined hand-eye coordination skills with a moving Pacman target test. Performance suffered an unspecified amount.
The article concludes that people suffering from the flu should avoid those activities that require quick thinking or quick reactions.
A Toronto scientist has found that a person who drinks may still have enough of an alcohol concentration in the inner ears 18 hours later to cause
disorientation. "We now have firm evidence" he said "that alcohol enters the inner ear and that it stays there after it has gone from the blood and the brain". He said that because alcohol affects the density of the fluid in the ear canals which monitor balance, the brain can receive conflicting information about the position of the head. This, in turn, can produce vertigo due to involuntary eye movements.
Based on this evidence, he advocates a 24-hr period between drinking and flying. (AIP AIR 2-11)
This research adds additional weight to that vital part of any pilot's training program that tells him that drinking and flying don't mix - and that any drinking is unacceptable within eight hours of flight.
PILOT WHO SMOKE, AND WHY THEY SHOULD STOP
[Canadian] Aviation Safety Letter 3/90
If you are a pilot who smokes, and have smoked seven cigarettes prior to going flying, your body won't be at the same altitude as the aircraft cabin. The carbon monoxide from the cigarettes will impair the ability of the haemoglobin in your blood to carry oxygen. With a 10% carboxyhemoglobin (coHb) saturation, or seven cigarettes, if the:
Aicraft Cabin Altitude = 5,000 feet ASL,
Your Physiological Altitude = 12,500 feet ASL, and if the
Aircraft Cabin Altitude = 10,000 feet ASL,
Your Physiological Altitude = 15,000 feet ASL.
Chain smokers consuming several packs of cigarettes a day will increase CoHb concentration to dangerous levels. Symptoms of dizziness, shortness of breath, nausea and mental confusion will be likely flying at typical altitudes, because of the deterioration of the oxygen carrying ability of haemoglobin due to carbon monoxide. Smoking is not good for you, and if you fly, its impact can be catastrophic.
A pilot's ability to maintain the desired level of alertness declines as a result of long stretches behind the controls of an aircraft.
On the average, after four hours of flying a pilot takes 20% longer to make altitude or course corrections.
Should an emergency occur, it will take a fatigued pilot three times as long to react as when he is fresh and alert. The value of rest pauses,when on a cross country flight, is obvious when one considers that after completing a four hour flight, all it takes is a five minute rest on the ground for a pilot to regain the same degree of alertness he had after his first hour of flight.
FATIGUE DURING LONG CONTESTS
SOARING JULY 1985
Most contest pilots will agree that Regional and National contests can be tiring. "Tiring", however, is a relative term, difficult to quantify. One way to breathe some life into the word is to compare the maximum cumulative flight duty for an Army pilot to the flight hours in a soaring contest.
The accompanying table shows the maximum cumulative flight hours for consecutive days with the factors to adjust for a number of different conditions (ie traffic, close to terrain, night, etc.) These data are plotted against the cumulative hours flown in consecutive days of contest flying.
It clearly shows that even a Regional Contest would exceed the flight hours limit set for Army pilots. A National Contest exceeds the Army limit by a factor of two or three depending on the length of the days (not just the task). Consider also that the Army limit is for people who are in physical condition that most of us can only remember, or dream about.
Now mix in a little fear, a little dehydration, a little bit of rust behind the stick with fatigue. The elements of an unpleasantness are at hand.
Ref: US Army Aviation Digest. August 1984, pp. 22-23.
60-| o = 5 hours a day line o
C | x = Army limits o
u 50-| o
m | o
u 40-| o
l | o x
a 30-| o x
t | o x
i 20-| x
v | x
e 10-| x
| x
H 00-|________________________________________________
r 0 1 2 3 4 5 6 7 8 9 10 11 12
s Consecutive Days
(Note: This article was taken from the USAF FLYING SAFETY issue, October 1986.)
by Major David H. Summers, M.D. MC FS 19th Air Refueling Wing Robins AFB, GA [Edited for Safety FAQ]
The standard procedures for sinus or ear block are:
1. Regain altitude until the symptoms are relieved.
2. Use a topical nasal spray (such as Afrin or Neosynephrine).
3. Attempt a slow descent.
Sinus block is preventable. Relieving the pressure before any damage is done can prevent a lot of pain and avoid a long course of medical treatment. However, there are several traps which can lead one down the primrose path.
First, the ears and nose vent out better than they vent in because the atmospheric air pressure increases at a greater rate at lower altitudes. As a result, there is more air to move into the sinuses in the last thousand feet of descent than there was in the first thousand feet. Therefore, be warned that sinus blocks usually occur during the approach.
Second, if you've never had a sinus block, it's easy to underestimate the amount of pain involved. People often think if there's a mild tinge of pressure at 4,000 feet, surely it will not be so bad at ground level. Wrong.
In those few seconds of final approach, the pressure change is so much that it can cause excruciating and incapacitating pain. The head feels like it is about to explode. Vision can become blurred or double. Blood vessels inside the sinus sometimes burst, filling the sinus with blood. Hopefully, there's someone else who can handle the controls. In the hospital, heavy doses of pain medications are given to the victim, and recovery can take weeks.
As with so many things in flying, disasters are averted by early intervention when the problems are still small. Follow standard procedures.
Of course, the best solution would be to swallow your pride and stay down when nose is "a little stuffy." But physiological incidents can creep up and surprise us all.
JET LAG (c)
[Reprinted with the kind permission of the Aviation Safety Institute]
(Editor Note: This article was taken from the Delta Airline ALPA newsletter, but we were unable to identify the author. This is the fourth article in a series. We apologize that we were unable to obtain the previous articles.)
[Edited for Safety FAQ]
Don't just complain about it-- do something!
Most of us would like to find a universal magic formula where duty times and fatigue are concerned. Do you think it's possible? If you think the answer is yes, then have I got news for you! I've been around this business a long time and there is still little evidence that pilots are satisfied that that their needs are being met regarding flight and duty time. In my 30 years (can it really be that long?) in this business, I have watched repeated negotiations over pilot agreements and more than one effort to change FAA flight-time duty-time rules without generally - accepted success. Is there a single way to satisfy everybody? Based on what we know, I don't beleve so. The best we can do is to live with what we have until it is changed. So this last article in the series will not provide a final answer, but it does offer recommendations based on our experience. These recommendations are my own and cannot be attributed to NASA, FAA, DAl, NTSB or even ALPA.
Recommendations for flight crews
1. Come to work rested. Commuters note: sleep taken just before duty extends the ability-to stay alert. HOWEVER--do not sacrifice the previous nights' sleep in order to get in an afternoon nap.
2. Remember, it causes greater fatigue and takes a lot of energy to stay awake if you are sleepy.
3. Exercise regularly. It helps you withstand periods of fatigue and sleep better.
4. Eat and drink right. Cereals, nuts, pastas, breads, etc., are good foods on the road. In flight, high protein but low fat foods are good selections. Eat regularly, even during all-nighters. Milk and bananas are better than a beer or something stronger to go to sleep on. (Alcohol tends to awaken you about four hours after drinking.)
5. AVOID, AVOID, AVOID dehydration. DRINK, DRINK, DRINK. Coffee is alright just before an approach because it awakens you. The rest of the time, juices--but not grapefruit juice--and water (a cup each two hours) will help eliminate fatigue caused by dehydration.
6. On layovers, arrange a full sleep period before pickup. On the eastbound Europe trips, sleep briefly on arrival (no more than two hours) and then get a full nights' sleep at normal bedtime in Europe.. Westbound trips are easier to adapt to because the day is extened rather than shortended. Carry earplugs or a noise generator (TV on channel with no station) to help you sleep through noises.
7. Know what works best for you and use it.
8. Understand problems common to all of us: sitting around is more tiring than working; reassignment- to an addititonal day of duty is worse than a trip of the same length: sleep before a departure is not as good as expected; and fatigue accumulates during a trip.
Safety recommendations for management
Consider three factors when scheduling:
1. Time on duty,
2. Time since last sleep, and
3., Time of day. Time on duty and time of day are the most important elements. Performance rises for the first five hours and then recedes , reaching it's lowest point and leveling off after 12 to 16 hours. Two-man crews are more subject to fatigue because of their constant flight monitoring versus three-man crews where breaks can be taken.
Time-of-day performance rises during the day and begins to fall in the evening, reaching it's lowest point about 5 a.m.. To schedule a crew for flight operations that occur at the lowest point of performance at end of a long duty period is begging for trouble.
1. Provide crews accommodations in hotels that are sensitive to airline crews' special needs.. Crews need to be able to sleep at unusual times and hotels should provide quiet - quarters, even if it is necessary to provide a special quiet wing. Food service should be available 24-hours a day.
2. Provide crews with wholesome inflight meals (low fat, high fiber, low salt). Quality drinking water should also be available.
3. Use internal publications to spread the word about rest and nutrition.
4. Provide a system that allows controlled and planned napping on the flight deck.
5. Understand that the hours of layover are more critical than the length of the layover.
6. Explore more specific information available at NASA Ames.
Recommendations for government regulators
1. Let flight crews know that the FAA does not wish them to fly if they are extremely tired. Protect crews from unfriendly managements who may choose to discipline them for following the FARs.
2. Intervene in flight crew scheduling where reason and recommendations from chronobiological experts dictate.
3. Create flight-time duty-time regulations which favor no special interest groups and take recognize applied chronobiology.
When it comes to illnesses and flying, there are two main concerns -your medical condition and the side effect of drugs.
Medical condition. We should decide, is the medical condition requiring medication exclusive to flying, and if it is, is it never exclusive, such as in multiple minor aliments that tend to affect us all, or is it temporarily exclusive, such as when we have a head cold, or is it permanently exclusive such as when we are dealing with insulin dependent diabetes mellitus. So in spite of the medication we are taking for the condition we should always consider, should we ground ourselves never, or temporarily for this condition. C.A.A. will decide whether it is permanently incapacit-ating. So while I am confining this presentation to the effects of drugs in aviation, I really think we should consider first whether this condition is to some extent incapaciating for flying, in the short term or the long run.
Drug side effects. If we decide the condition is not going to exclude us from flying, but we decide then to medicate ourselves with some over-the-counter medication, we should decide whether the side effects of the medication are likely to interfere with our ability to fly. Such an interference is sedation which can be produced by tranquillizers and some antihistamines which are available over-the-counter, such as Benadryl. These antihistamines are often used as a decongestant in cold remedies, so look at the label first, or if you are uncertain ask the pharmacist if any of the ingredients are likely to be sedating. Quite often when antihistamines are prescribed, the label on the bottle will say "Do not fly for six hours after taking this medication", because they may have a sedative side effect. We have to bear in mind too that this sedation is not necessarily to the extent that one will fall asleep while flying. It may be much more subtle, in that we might make minor oversights such as forgetting to look to see if the dive brakes are closed before taking off, or forgetting to push on the canopy once it is closed to make sure it is locked.
These are very minor oversights that could easily occur which could have far reaching effects, and could easily be produced by a slightly sedating antihistamine.
We also have to make sure the drugs don't produce agitation. Compounds which can produce agitation are caffeine which is present in coffee. It is also present in cold remedies because these as we have said may contain Benadryl or an antihistamine which has a sedating side effect so caffeine is added to the mixture to produce a slightly stimulating effect to counter the sedation. Unfortunately however, a plus and a minus do not add up to zero here, so we have a slightly sedating drug and we imagine we are countering it with a slightly stimulating drug. They don't cancel out. We have two different drugs which are struggling with each other and we don't have a new effect . . . . we have two different drugs. It is worth being aware of that.
Another drug that may produce agitation is Pseudo-Ephedrine. This is commonly used as a decongestant in cold medications. It is a compound which is related to adrenalin which is a stimulant, which as we know can agitate, raise your pulse rate, and induce nervousness and even anxiety. Some people may be unduly sensitive to sedating effects or the agitation effect of some of these medications, so we should know from past experience whether we are going to take an over-the-counter medication before we fly, and we should consider if we should be flying in view of the medical condition we have.
Having put in these two caveats of should we fly with this medical condition, or would the side effects of the medication preclude us from flying, let us look now more closely at some medical conditions and the problems that they present.
Diseases and Drug
Allergy. Allergy of the upper respiratory tract produces swelling and congestion of the mucous membranes which might block off nasal airways and sinuses or ear passages. This then can cause obstruction which becomes a problem when we get to even comparatively low altitudes, because with obstruction of a closed ear space we get different pressures which we cannot equalize and the increased pressure in blocked off cavities produces pain which may well interfere with our ability to fly or our ability to concentrate. Once obstruction has occurred in the upper respiratory airways there may now be secondary infection in much the same way that we block off a flowing stream - it becomes stagnant. So we may have secondary infection with its debilitating effects as well.
Allergy can also produce asthma, which is a contra-indication to flying of course. However asthma isn't just necessarily the wheezing situation we are all aware of. It may present itself as an irritating cough which does not settle, so we must be aware that allergy can produce this also. More seriously however, people can experience angioedema in which there is unexpected sudden swelling of the lips or tongue and airway, which could obstruct the airway, and within minutes this condition is potentially fatal. If we have had episodes of this in the past and we are experiencing allergy we shouldn't fly under these circumstances.
Another major medical problem associated with allergy is anaphylaxis, which is a sudden serious severe state of collapse, catastrophic drop in blood pressure, loss of consciousness and associated abnormal heart rhythms and not infrequently death. This usually appears very suddenly and can proceed very quickly. It can be induced by such a simple thing as a wasp sting. Usually people who are susceptible to this are aware of it, but this is an allergic condition which would preclude us from flying if we know we have this in our past history.
If we decide to fly with minor elements of allergy, then we should not fly for six hours after the onset of the illness to make sure that the effects of the medication have worn off and that the allergy has in fact resolved. Medications that we use to treat allergy are commonly available over-the-counter, such as Benadryl, and any antihistamine of this nature may produce drowsiness, dizziness and fatigue, none of which are compatible with flying. However, there are some over-the-counter antihistamines which are known to be non-sedating and which are compatible with flying. Such examples are Hismanal and Claritin, to name just two.
Anesthetics. Anesthetics in this case means local anesthetics such as administered in the dentist's office or maybe in the emergency room to suture a laceration for example. Anesthetics often contain adrenalin which is used because it blocks off blood vessels and makes sure that the local anesthetic injected into an area does not get carried away, thus prolonging its effects at the local site. However as we have said, adrenalin can produce excitement, rapid pulse rate and headaches. It may even in some circumstances produce convulsions. Therefore it is recommended that a pilot shouldn't fly for 12 hours after having had a local anesthetic.
Antibiotics. If we are taking antiboiotics we should also, as we mentioned above, consider the need to take the antibiotic. So, in other words, if we have say bronchitis this might produce shortness of breath and some relative hypoxia if we are going to significant altitudes, so the original condition rather than the antibiotic maybe a reason not to fly. If we are taking antibiotics try to make sure that you know your response to this antibiotic from having had it previously so that you may not get an allergy reaction to it while you are flying. Erythromycin is an antibiotic which is frequently used and it may produce stomach upsets and we could do without this problem when we fly. Penicillin, to take another example, not uncommonly can produce diarrhoea, and this is also undesirable as gliders are not equipped with washrooms or stewardesses, so that if you know that penicillin is likely to do this for you, don't fly.
Cardiovascular drugs
Digitalis This drug is used for certain medical problems which in their own right preclude people from flying, so if you are on this drug you shouldn't be flying until you have a clearance from C.A.A.
Diuretic These tend to reduce potassium in the blood stream and this can produce abnormal heart rhythms, so diuretics are not suitable for flying. Of course, diuretics as we know increase our urine output and if one is accustomed to flying sailplanes for hours at a time this problem speaks for itself.
Hypertension If you are taking these drugs and are uncertain of their approval, ask your local Civil Aviation Medical Examiner.
Cold medications These may contain antihistamines, Pseudo-Ephedrine or Codeine and the side effects of these have been discussed previously in this presentation and also the problems associated with congestion and obstruction that may apply with colds.
Digestive system Antacids are acceptable except for Enos, baking soda or Alka Seltzer because these have a tendency to produce gas which at altitude expands and may produce abdominal cramps. This is quite undesirable while flying, so it is all right to take antacids which are not gas producing. Anticolic medication such as Donnatal, may produce blurred vision. Laxatives may produce cramps or diarrhoea.
Immunizations Tetanus and oral polio do not interfere with flying. However the combined injection of diphtheria, pertussis, tetanus and polio, and other immunizations produce local pain and may make the person feel unwell. This being so, it is recommended that you shouldn't fly for 24 hours after receiving that type of immunization.
Pain killers ASA (Aspirin) in larger doses may produce drowsiness or commonly stomach upsets. Another drug in this category which is available over-the-counter is Advil and it is in the same family of drugs as ASA and also produces the same problems. One of the difficulties with medications such as Advil is that it may produce stomach ulcers, which is all very well if you have pain associated with it, because it is an indication you should stop the medication. However sometimes Advil and other drugs in this group may produce a silent stomach ulcer so that the patient is unaware that he has a problem with it, and may in fact be having a bleed from a painless stomach ulcer and not be aware of it. So if you need to take Advil make sure that you are tolerant to it before you fly, and also that it doesn't produce sedation. Codeine and injectables are usually narcotic-type pain relievers. The pain itself of course precludes flying if it is of the extent that you need a narcotic, and also narcotics produce sedation, so this type of pain killer should not used by a pilot who is flying.
Pesticides These relate more to agricultural pilots but also to the avid home gardener. Chlorinated pesticides such as DDT, TDE and Methoxycholor may produce vomiting, inhibitors such as Parathion, Malathion, TEPP may produce headaches, blurred vision, dizziness and convulsions. These are mentioned because if we inadvertently get these sprayed on the skin, don't recognise it, and absorb this through the skin or absorb the vapour from the spray, we may suffer from these side effects which are incompatible with flying.
Sedatives Barbiturates have a long half life and may well give impaired judgement. If somebody needs to take a sedative they shouldn't be flying in the first place. Secondly with the long half life there may be some minor effects persisting from the barbiturate which may impair your judgement. Therefore it is recommended that you don't fly for 24 hours after taking a barbiturate. The same proviso applies to sleeping pills.
Stimulants Benzadrine and Dexadrine are common appetite suppressants. These produce agitation which may impair judgement and make a pilot over-reactive. Caffeine also is a stimulant and may produce agitation and nervousness in some people. Therefore don't fly for 6 hours after loading up on appetite-suppressants or caffeine.
Tranquilizers The condition requiring the use of a tranquilizer would exclude the pilot from flying and as well the tranquilizer itself may produce drowsiness, complacency and weakness. Some of these medications also may well have a long half life, therefore don't fly for 24 hours after taking the medication.
Antidepressants Depression itself is a contra-indication to flying. Commonly antidepressants may well have a very long half life and they may produce blurred vision, sedation, agitation, abnormal heart rates and a drop in blood pressure in susceptible people. Therefore don't fly for one week after taking an antidepressant.
Hypoglycemia A pilot who has been flying for several hours without taking nourishment will have his blood sugar gradually fall. He has thoughtfully packed in some sweets or high calorie foods that boost his energy level. However these foods produce a sudden sharp rise in blood sugar and this is now countered in the body by a sudden sharp rise in insulin production, the function of the insulin being to transport this blood sugar across the tissue membranes into the muscles. Because the insulin level has suddenly risen, now the blood sugar level starts to fall. However we can't suddenly turn off the insulin as quickly as the blood sugar falls, so the raised insulin levels may continue to lower our blood sugar below a desirable level before the insulin quietly returns to normal. During this rebound phase we may be hypoglycemic which means our blood sugar may be lower than it should be. Under these circumstances our body now decides to try and counter this condition itself by producing adrenalin whose effect is to release stored sugar from the liver to put the blood pressure back up to counter the hypoglycemia which in fact does occur. However, as we mentioned earlier, adrenalin itself can produce agitation and excitement and nervousness and rapid pulse. This phenomenon is known as rebound hypoglycemia.
In order to minimize this, it is worth having a good intake of protein-type of food before we takeoff. Protein produces a slow rise in blood sugar and therefore a correspondingly slow rise in insulin. Because protein takes quite a while to digest, it produces a slow offset. This is matched by a slow offset of the insulin production, and we don't get rebound hypoglycemia. So it is preferable to avoid too much high calorie foods. If you are going to eat this though, certainly take some protein containing foods along such as cheese or boiled eggs to add the protein to the snack to avoid rebound hypoglycemia.
Fatigue Fatigue fragments integrated mental activities. It shortens the attention span and degrades accuracy and judgement, therefore we should address all the factors that are likely to add up to fatigue. Don't fly without adequate rest or sleep or with an empty stomach or with a head cold which for a pilot is a serious problem, or sprains, strains or a cast, because swelling inside these may produce compression and pain.
Common sense Flying is a state which involves man and machine. The machine is always monitored very carefully, most accidents are due to the man in the equation.
Major health problems are easy for us to spot and we are all aware of those, and using our common sense, we decide not to fly. However, minor health problems may be fairly innocuous and easy to overlook. If we then fly with the problem, we may find that we get fatigued much earlier in the flight as a result of vibration, dehydration, noise, hypoglycemia, etc. So never underestimate the effect of a minor health problem because when other factors are added, it may become important to us at the end of a long flight - we may suffer from fatigue a little earlier and make an error in judgement in, say, an off-field landing.
Conclusion
In the foregoing I have spoken in generalizations to create an awareness of the possible adverse effects of minor ailments in conjunction with common over-the-counter medications which may be taken to combat them. It doesn't mean that we can't fly with these, but we should not forget to DI the pilot first to make sure that these are within acceptable limits. This way we can all enjoy our flying and do it safely.
DISORIENTATION
[Canadian] Safety Letter (sometime in 1995)
Republished from: Medical Facts for Pilots, Publication AM-400-90/1. FALL Civil Aeromedical Institute. Aeromedical Education Division. AAM-400, P.O. Box 25082 Oklahoma City, Oklahoma 73125
If you have ever experienced the effects of disorientation while flying, you know how dangerous this condition can become. It can cause motion sickness, vertigo, and loss of control. This brochure describes the physical causes of disorientation and how to avoid it.
THE INNER EAR
Most problems related to disorientation can be traced to the inner ear, a sensory organ about the size of an eraser on a pencil. It may well be the most well protected organ in the human body, and for good reason. It;s the key to our ability to balance when on the ground, or to remain oriented in space when we fly.
The inner ear is similar to a three axis gyro. It detects movement in the roll, pitch and yaw axes that pilots know so well. When the sensory outputs of the inner ear are integrated with appropriate visual references and spatial orientation cues from our bodies, there is little chance of experience disorientation.
VISION AND THE INNER EAR
The problem occurs when the outside visual input is obscured, and the seat of the pants input is ambiguous. Then, you're down to just the output form the inner ear- and that's when trouble can start.
Fluid in the inner ear reacts only to rate of change, not sustained change. For example, when you initiate a banking left turn, your inner ear will detect the roll into the turn, but if you hold the turn constant, your inner ear will compensate and rather quickly, although inaccurately, sense that it has returned to level flight.
SENSORY ILLUSIONS
As a result, when you finally level the wings, that new change will cause your inner ear to produce signals that make you believe you're banking to the right. This is the crux of the problem you have when flying without instruments in low visibility weather. Even the best pilots will quickly become disoriented if they attempt to fly without instruments when there are no outside visual references. That;s because vision provides the predominant and co-ordinating sense we rely upon for stability.
Perhaps the most treacherous thing under such conditions is that the signals the inner ear produces-incorrect though they may be-feel right!
These sensory illusions occur because flight is an unnatural environment. Our senses are not capable of providing reliable signal that we can interpret and related to our position in three dimensions-without visual reference.
"SEAT OF THE PANTS" FLYING
Does "seat of the pants" flying work in IFR weather? Judge for yourself: Anyone sitting in an airplane that is making a coordinated turn, no matter how steep, will have little or no sensation of being tilted in the air-unless the horizon is visible. Similarly, it is possible to gradually climb or descend without a noticeable change in pressure against the seat. In some airplanes, it is possible to execute a loop without pulling negative Gs, so that without visual reference you could be upside-down without being aware of it. That;s because a gradual change in any direction of movement may not be strong enough to activate the fluid in the semicircular canals, so you may not realise that the aircraft is accelerating,decelerating, or banking.
INSTRUMENT FLYING
The obvious method to prevent disorientation is the instrument rating. But that rating alone is no automatic guarantee because there is no such thing as "knowing how to fly on instruments". You must continue to practise your skills. You are either formally trained and current-or you are unqualified.
So, don't try to fly through a cloud bank or "scud-run" in low visibility conditions if you aren't a current instrument-rated pilot. For the unqualified pilot, the sudden loss of visual reference is similar to a sudden loss of eyesight. Emotional pressure surge and you can lose your orientation in less than 20 seconds. You can be starting the infamous aerobatics manoeuvre known as the "graveyard spiral", and not even know it.
All pilots should check the weather conditions and use good judgement in flight planning. The VFR pilot should avoid low-visibility conditions, such as night flying, fog, clouds and haze.
And, if you're instrument rated and current, you should always trust your instruments. Those gyros are much more reliable than the ones inside your head!
Since the early days of information dissemination, those charged with expert status in any given field have at times sought refuge from reality, especially when speaking in public forums. With the advent of printing, and later voice and image recording technology, hundreds of head-in-the sand statements have seen permanent circulation. The animal most famous for having its head in the sand is the subject of the following list of aviation reality-denial statements. The Oliver Award nominations, made by the membership of The Ostriches Anonymous Association, are in.
The association, founded by retired American Airlines Captain Dr. Robert Besco, has compiled a brief list of notable reality (or as the OAA maintains, "risk") denial statements made during recorded aviation history. They are anonymous -- some paraphrased -- in keeping with the credo of OAA, which reads in part ". . . to enlighten and entertain, never to embarrass . . ." Here are our favorites.
Selected Olivers, Through the Years
1990 "My client's blood alcohol did not degrade his flight deck performance. He is an alcoholic and has a high degree of tolerance." -- Attorney
1989 "The structural failure was a rogue accident. Inspection and maintenance procedures do not need to be changed." -- Government Official
1989 "Don't you realize how much negative response your safety recommendation will generate?" -- Senior Military Officer
1988 "Since this safety procedure cannot guarantee that we will never have another accident, we should not publish it." -- Aviation Publisher
1988 "The whole industry is now so sensitized to the no-flap takeoff error that it will be many years before we are at risk from a no-flap mistake being repeated." -- Government Official (address made to a professional organization 23 months after the referenced no-flap accident, and one month before the next no-flap accident).
1986 "Why should we spend the money to fix that problem? It hasn't caused any accidents." -- Airline Executive
1984 "They will teach you about the Digital Guidance System during your Initial Line Operating Experience." -- Airline Flight Instructor
1983 "We don't need to raise our pilots' wages. We can find plenty of licensed pilots to hire at less that $1500/month." -- Airline Executive
1982 "Captain, if your only abnormal indication is a high vibration indication on No. 3 engine, you might as well continue on to your destination." -- Airline Hotline Technical Advisor (advice given two hours before the complete in-flight disintegration of a multi-million dollar engine).
1977 "The pilots involved in the accident chose to ignore everything that they were trained to do." -- Airline President
1975 "The vibration indicators are so unreliable that we should remove them from the engines." -- Jet Engine Designer
1970 "It's great to fly with fully-qualified and experienced captains. You don't have to be constantly on alert for their mistakes." -- Airline Co-pilot
1969 "We can make this cargo door lock fool proof. But we cannot make it damn fool proof." -- Aircraft Manufacturer
1968 "If you test that warning system every flight, you'll wear it out." -- Check Airman
1967 "I can squeeze in one more pass at the target before I am down to minimum fuel." -- Fighter Pilot
1965 "Blue Leader, it is my personal feeling, based on my current analysis of the situation, that you might want to reconsider your current plan of action. I recommend that you seriously consider an alternative tactic which would involve the detachment of the bogey from you six o'clock position by responding promptly with the following suggestion: 'Blue Lead, Break Hard Left, Now!'" -- Wingman (warning made after completing leadership sensitivity and assertiveness training).
1962 "We can't afford a design that will protect us from multiple failures." -- Airframe Manufacturer
1960 "A system that is triply redundant is already over designed." -- Airframe Executive
1958 "We do not need a backup for that system, it will only fail once in 1000 years." -- Airframe Manufacturer
1957 "I'm going to pass you, but don't ever do it that way on the line." -- Instructor
1956 "If we distribute educational materials to our pilots on accidents, incidents, hazards, and risks, it might be picked up by the media and put us at a competitive disadvantage." -- Airline Executive
1955 "Flying transcontinental flights of over 8 hours is unsafe unless we get paid more money per hour." -- President of Pilot's Union
1948 "It had to be pilot error. Thousands of pilots have used the three pointer altimeter without misreading it." -- Avionics Designer
1944 "The warning horn was making so much noise that I couldn't hear the tower telling me to put the landing gear down." -- Pilot and Designer
1940 "The Japanese don't have the engineering, manufacturing, or military training capability to design, build, and fly airplanes in combat that are as good as ours." -- U.S. Army Corps General
1933 "The best protection is to accept and build upon American tradition and not try to purchase freedom with gadgets such as strategic, long-range bombers." -- Secretary of War
1930 "Present-type airplanes would burn up at 500 mph. The terrific heat caused by the air resistance would melt steel." -- Prominent Author and Engineer
1926 "We can deliver the mail in any weather." -- Airmail Pilot
1920 "Professor Goddard does not know the relation of action to reaction, and of the need to have something better than a vacuum against which to react." -- Editorial in Major New York Newspaper
1914 "My son-in-law was unfortunate in that he tried to fly on a day in which there was not much lift in the air. He survived the crash through a combination of superior skill and good fortune." -- Lt. General
1913 "Can't we buy just a few airplanes and let the pilots take turns flying them?" -- U.S. President
1903 "We hope that Professor Langley will not put his substantial greatness as a scientist in further peril by continuing to waste his time, and the money involved, in further airship experiments." -- Editorial in Major New York Newspaper (published one week before the Wright brothers' first flight).
1890 "I have not the smallest molecule of faith in air navigation, other than ballooning." -- English Nobleman and Physicist
746BC "It won't matter if I fly just a little bit higher." -- Pilot of the firs Ultra Light
747BC "It will be OK as long as you don't fly too close to the sun." -- Builder of the first Ultra Light Kit
AVIATORS BREATHING OXYGEN (c)
[Reprinted with the kind permission of the Aviation Safety Institute]
There is a rising concern among pilots regarding the proper servicing of breathing oxygen in general aviation aircraft.
The following information has been excerpted from Military Specification MIL-0-27210,MIL-STD-1551, MIL-STD-101, and Federal Specification BB-0-925a. This is an effort to clarify standards and container markings. Some precautions are included which may help eliminate the possibility of servicing an aircraft system with other than aviators breathing oxygen. Oxygen for aircraft use is stored or contained in three forms - gaseous, liquid, or chemical. The liquid oxygen system is used in some military aircraft, chemical in some large aircraft, but most general aviation aircraft use the gaseous oxygen system. This article relates to gaseous aviators breathing oxygen.
Gaseous oxygen is colorless, odorless, tasteless and about 1.1 times as heay as air. Oxygen can exist as a solid, liquid, or gas, depending upon the temperature and pressure to which it is subjected. At atmospheric pressure, oxygen exists as a solid at temperatures below its melting point, -361 degrees F (-218 degrees C). Solid oxygen turns into a liquid at its melting point and remains in this state until the temperature rises to its boiling point, -297 degrees F (-183 degrees C). At this latter temperature, liquid oxygen vaporizes into the gaseous state. Conversely, gaseous oxygen will turn into liquid, at atmospheric pressure, by cooling to a temperature below -297 degrees F.
Air, which contains about 21 percent oxygen by volume, is the principal source of liquid and gaseous oxygen. Air is compressed and cooled to liquefaction, whereupon the liquid oxygen is seperated by distillation and taken off as liquid product, or gasified for gaseous product.
Oxygen is a very reactive material, combining with most of the chemical elements. The union of oxygen with another substance is known as oxidation. Extremely rapid or spontaneous oxidation is known as combustion. While oxygen is non-combustible in itself, it strongly and rapidly accelerates the combustion of all flammable materials; some to an explosive degree. Oxygen, as supplied, contains a minimum of 99.5 percent by volume of pure oxygen. The remaining 0.5 percent consists principally of argon, plus various organic and inorganic compounds in amounts measured in the parts per million range.
Federal Specification BB-0-925a states that aviators breathing oxygen should be in accordance with Military Specification MIL-0-27210. MIL-0-27210 specifies that aviators breathing oxygen shall have a minimum purity of 99.5 percent by volume and that the moisture content of aviators breathing oxygen should not exceed 0.005 milligrams of water vapor per liter of gas at a temperature of 70 degrees F, and a pressure of 760 millimeters of mercury.
Oxygen comes in cylinders under high pressure. Present-day cylinders are safe if handled properly. Upon receipt of oxygen from a commercial supplier, each cylinder should be inspected for the following:
1. Proper printing and marking (green with a 2 to 2-1/2 inch white band, 9 to 11 inches below the collar and stenciled or tagged aviators breathing oxygen or aviation oxygen).
2. Valves are tightly closed.
3. Safety caps or safety plugs are leak-tight and secure.
4. Valves protective caps are installed.
5. Evidence of grease of oil on the valves or cylinders. (Hands, clothing, and tools must be free of oil, grease, and dirt when working with oxygen equipment. Traces of these organic materials near compressed oxygen may result in spontaneous combustion, explosions, and/or fire.)
Before servicing any aircraft, consult the specific aircraft maintenance manual to determine the proper type of servicing equipment to be used. Aircraft should not be serviced with oxygen during fueling, defueling, or other maintenance work which could provide a source of ignition. Oxygen servicing of aircraft should be accomplished outside hangars.
In summary - aviators breathing oxygen going into aircraft oxygen systems should meet the purity and moisture specifications as contained in Military Specification MIL-0-27210: purity - 99.5 percent by volume (minimum); moisture - 0.005 milligrams per liter of gas (maximum).
DO:
1. Check that only "aviators breathing oxygen" is going into the aircraft system.
2. Reject any oxygen that has an abnormal odor (good oxygen is odorless).
3. Follow applicable instruction regarding charging, purging, and maintenance of aircraft oxygen systems.
DO NOT:
1. Use oil or grease around oxygen systems.
2. Expose oxygen containers to high temperatures.
3. Confuse aviators breathing oxygen with "hospital/medical" oxygen. (The latter is pure enough for breathing but the moisture content is usually higher which could freeze and plug the lines and valves of an aircraft oxygen system.)
LOW ALTITUDE HIGH SPEED MILITARY ROUTES (c)
[Reprinted with the kind permission of the Aviation Safety Institute]
All military services have mission requirements that place their aircraft at very low altitudes and over a range of speeds from 60 knots to 600 knots. The military services have received waivers from FAR Part 91 that will allow them to fly faster than the 250 knot limit below 10,000 feet.
Pressure from the aviation community has forced the military to publish all low altitude routes and, therefore, help you in your flight planning and cross country flights. There are several key safety tips for you to remember and use.
All low altitude routes are either in print or being prepared for publication. Every Flight Service Station is supposed to have complete descriptions of routes in their areas of communication coverage. Therefore, your best source of low altitude route status is from the FSS.
When planning a flight, you should check wih FSS to determine the proximity of routes to your intended route of flight. If one or more exists close to or on your route, be sure to learn the status of the route. That is, when it will be in use and at what altitudes and airspeeds.
Most low altitude routes are to be flown under IFR procedures. This means that the military pilot must file an IFR plan and give accurate route entry and exit times. They will also specify a block of altitudes. For example, they would enter at 1345 Greenwich Mean Time (Z), fly between 2,000 and 4,000 feet MSL, and depart the route at 1455Z. They must report their entry time to the nearest FSS and departure time to the nearest FSS at the departure point. Then, the FSS's in the affected area must alert all pilots of the status of the route, giving times and altitudes.
The rest is up to you. You should fly at altitudes that will likely assure adequate separation from high speed military aircraft. These aircraft include everything from helicopters to A-7 and B-52 or F-111 aircraft. They are very difficult to see for three reasons:
1. They are moving very fast.
2. They are usually painted with camouflage markings.
3. They are usually below your flight altitude.
Try to stay away from the entry and departure points of the low altitude routes. The military aircraft will either be descending or climbing very fast. If possible, cross the published route at right angles to minimize your time in the area.
If you have any doubts about the routes, call the nearest flight Service Station. You may also obtain information from FBO bulletin boards, Airmen's Information Manual (AIM), and published Notices To Airmen (NOTAM).
Above all, keep your head moving while flying. A pilot who does not scan his complete view of the outside world is taking unnecessary chances. Remember, if you are in VFR conditions, you must keep yourself separated from other aircraft.
Don't trust anyone's word for things, assume that the other guy is incorrect, and cover your onw tracks. You are the person responsible for your aircraft.
NOTE: This article comes from the FAA General Aviation Airworthiness Alerts, AC No. 43-16, Alert No. 77, December 1984. We thank the FAA for making this important safety feature available.
MEKP
Several air carriers and fixed base operators have recently reminded their maintenance personnel of potentially serious hazards in the use of certain catalysts used to "lay up" fiberglass or as hole fillers.
Methyl ethyl ketone peroxide (MEKP) is in the family of organic peroxides that are intrinsically unstable and, in large quantities, potentially destructive. In using them, mechanics (and homebuilt owners) must observe definite safety precautions and have a knowledge of their potential.
At a safety conference, an eye specialist urged caution in the use of a catalyst or hardener that is added to the fiberglass resin before the resin is applied. The specialist said a drop of this catalyst in the eye will progressively destroy the tissue and result in blindness. This will occur in some instances even when an attempt has been made to wash the catalyst from the eye.
Furthermore, once the chemical has begun to destroy the eye, there is no known way of stopping the destruction or repairing the damage.
The specific toxic agent involved is MEKP. In tests using laboratory animals, MEKP in solutions of varying concentrations was found to cause eye problems ranging from "irritation" to "severe damage." The maximum concentration producing no appreciable irritation was a solution containing 9.6 percent MEKP.
Material published on the subject indicates that washing an effected eye within four seconds after contamination prevented injuries in all cases, but no known chemical neutralizer has been reported.
Suggested protection for catalyst users is protective glasses and the immediate availability of a bland fluid such as water for a thorough washing of the ocular tissues.
Reports of one experience described disastrous results. The victim had both eyes contaminated while fiberglassing a chair at home. Although he made an effort to wash out his eyes, several minutes apparently elapsed before he found water. The use of one eye was lost immediately, the other gradually deteriorated over a period of about 8 years. Its deterioration was described as resembling that resulting from World War I mustard gas burns.
The hazard associated with fiberglass resins was previously unknown to those attending the safety conference, although many had used fiberglass resin at home or at work. This hazard also may be unknown to you and to your family members who may have occasion to use a similar type of resin and catalyst when working with fiberglass or hardeners used in liquid casting plastic.
Precautions
Before using any of these catalysts, check their chemical composition and then take the appropriate precautions. The cost of a pair of safety goggles is a small price to pay for the protection of your eyesight.
No epoxies use MEKP as a catalyst. MEKP is used to catalyze polyester resins, which are used for fiberglass resins, certain casting resins and in some paints and hole fillers. The mere mention of polyester resin makes it almost certain MEKP is the catalyst.
While epoxys do not appear to be as potentially damaging to tissue, all are accompanied by precautions regarding toxicity. Handle them exactly as directed in the printed instructions. Any other procedure may cause unstable peroxide to react violently. The American Insurance Association has a relatively long list of manufacturing and storage fires and explosions where peroxides (including MEKP) were involved.
When using catalysts in this family of chemicals, adhere strictly to mixing, application and storage instuction provided with each compound.
HAZARDS OF WOODEN AIRCRAFT - WOODEN STRUCTURES (c)
[Reprinted with the kind permission of the Aviation Safety Institute]
[Edited for Safety FAQ]
All wood-constructed aircraft from antiques and amateur-built to the latest models just off the assembly line are subject to one unique problem -- wood can rot.
Wood decay, or rot, is caused by a fungus, a form of plant life which feeds on and destroys the cellulose content and structure of the wood fibers. The seed of a fungus plant is a microscopic, airborne spore, present in almost all common environments. These spores will endure in a dormant stage for years, and spring into growth when the wood becomes damp. A germinating spore sends out minute hairlike strands which seek out the cellulose of the wood and absorb it. These filaments break down the cell walls of the wood with a resultant loss of strength. As the fungus develops, the wood darkens because the microscopic hairs become numerous and form visible masses. In advanced stages, the fungus can even produce boreholes, when highly localized areas of fungus penetrate the walls of adjoining wood cells.
Incidentallly, the term "dry rot", is a misnomer. There is no such thig as dry rot. Moisture must be present for rot to develop in wood. The term "dry rot" seems to have originated far back in nautical history when sailors discovered powder in pieces of wood, dry because the rotting process was complete, and called it dry rot.
Wooden aircraft, no doubt, have they special virtues and deserve the loyal and persistent following they enjoy among purchasers of type-certificated planes, as well as amateur builders. They can be flown safely as long as they are maintained properly. Maintenance of wooden aircraft requires some special precautions, including the following:
Keep the aircraft as clean and dry as possible (dirt and moisture promote fungus growth).
Store wooden aircraft in a hangar if possible, preferably a heated hangar, especially in winter. Admittely, this is becoming increasingly difficult today, as hangar space becomes more precious, but it is very important for these aircraft.
Keep an effective waterproof coat of paint on the skin and do not allow breaks or cracks to go unremedied. If you buy a wooden aircraft with cracked paint, have the fabric or panels removed for a thorough inspection of the spars before flying or repainting. There are a number of good wood preservatives available which, when properly impregnated into the wood, retard deterioration. Incidentally, regular paint and varnish do not necessarily ward off wood rot. When you paint or varnish you can actually seal many spores to the surface of the wood, and moisture can penetrate the painted surface under humid conditions.
Thorough inspection in in order for any wooden aircraft stored outside or kept in a damp, unheated hangar. Most wood-constructed airplanes have drain holes at the bottom of each wood component, to circulate air and reduce moisture. It is imperative that these drains be kept open so they can function properly. Make certain you know the location of all the drain holes on you aircraft, and inspection them at every preflight check.
If the propeller is wood, it too should be watched for signs of decay, particularly in the critical area around the bolts. Given enough time, moisture will penetrate virtually any surface.
Interior inspection costs more than eyeballing the surface, but it lets you fly with a sense of assurance and peace.
Wood constructed aircraft should be thoroughly inspected in accordance with the manufacturer's recommendations by knowledgeable, qualified personnel. Compliance with applicable airworthiness directives is a must. Advisory Circular 20-106, Aircraft Inspection for General Aviation Aircraft Owners, is designed to familiarize owners, pilots, and others with inspection procedures.
Advisory Circular 43.13-1A, Acceptable Methods. Techniques and Practices - Aircraft Inspection and Repair, contains illustrations of acceptable repairs to certain parts of wood-constructed aircraft.
REMEMBER, IT IS NOT THE HEAT OR COLD THAT CRIPPLES YOUR WOODEN AIRCRAFT, IT'S THE MOISTURE.
[Edited for Safety FAQ]
Numerous reports, received annually, identify structural corrosion problems and other types of hazardous conditions that have developed because drain holes in the aircraft were partially restricted or completely closed. Many of these reported problems required an appreciable period of time to reach the state of deterioration found. Therefore, it may be assumed the drain holes were also clogged for at least a comparable time interval.
Regardless of materials used to cover an aircraft, drain holes are necessary to prevent the accumulation of liquids and serve as air vents. To assure the satisfactory accomplishment of these functions, the manufacturer located these drains in specific locations at the low points of wings, control surfaces, fuel compartments, the fuselage belly, etc. Should it be necessary to replace the skin on an aircraft, it is essential that new drain holes be provided at these same locations. Failure to do this creates a suitable environment for future costly problems. Once opened, drain holes require no maintenance other than a periodic check to determine that they have not become clogged. The skill and time involved in doing this would indeed be a small price to pay for preventing the development of a condition that may not be suspect or detected until too late.
EPOXY PAINTS (c)
[Reprinted with the kind permission of the Aviation Safety Institute]
North Central Airlines (now Republic Airlines) publishes the "Ungarbled Word." A recent issue contained an account of an employee's experience with an epoxy-based paint used to finish a model glider. As he tells it, he spray-painted the bird in his heated garage workshop. He sprayed a tack coat and stepped out. Twenty-five minutes later, he stepped back in, sprayed a finish and stepped out again. Total time in the spray area was less than 4 minutes. He then proceeded to clean his spray gun. About one-half hour later, he noticed a strong smell of algae -- like a stagnant swamp. An hour and a half later, he was experiencing pains in his lower rib cage. The pains spread throughout his chest cavity; and in short order, he found himself in a coronary care unit.
Here's what he says about it: "Even though I suspected possible poisoning from the epoxy and took a can of it to the hospital with me, an education program followed which should be shared with everyone:
1. There is no antitoxin (as in the case of a snake bite) or reversing-type chemical to render the effects of the epoxy formula harmless.
2. If you are going to live, you live; if not, the staff just has to watch you die.
3. The resins and hardeners inflame the tissues in the lungs and surrounding areas near the heart; the effect is like a coronary , but no traces can be found later.
The moral is obvious; if you are going to spray epoxy, do it outdoors or in a vented spray booth. If you are going to dry-sand epoxy, wear a carbon-activated face mask -- the powder or dust is dangerous as the wet spray. Final note; the effects are cumulative over a period of time; and when your tolerance has been reached, there is no reversing the process."
From FAA General Aviation Airworthiness Alerts, Alert No. 55, February 1983.
SOARING ASSOCIATION OF CANADA
L'ASSOCIATION CANADIENNE de VOL à VOILE
FLIGHT TRAINING AND SAFETY COMMITTEE
SAFETY AUDIT
.................................................................
club
.................................................................
address
This Audit was completed by the club on
................................................. date
Soaring Association of Canada
111, 1090 Ambleside Drive, Ottawa,
Ontario, K2B 8G7
Revised 1995 June
Copy sent to the Association
.............................................. date
SOARING ASSOCIATION OF CANADA
L'ASSOCIATION CANADIENNE de VOL à VOILE
FLIGHT TRAINING AND SAFETY COMMITTEE
SAFETY AUDIT
INTRODUCTION
Operations or SAFETY Audits have been used for some time in industrial companies to assess their performance in safety and operational areas. The Safety Audit is often used in inter-company competitions. The Association does not have a formal audit of clubs, nor does it intend to have. However it has had a form of "audit" in place for new clubs for several years.
It is the purpose of these notes to introduce your club to the concept, and if you wish, to allow your club to use it to assess how you would rate. The benefits would all depend upon how the audit is applied, and how the club members view such an "audit" or check. This could be used, for example, to enhance safety awareness at a club, and to help (particularly a "young" club) to assess its organisational structure as it pertains to the flying operation and ultimately to safety.
BACKGROUND
Safety is not only up to the pilot as he or she climbs into the cockpit, but is a continuing concern of all of us. Or should we say "should be"? Whether or not we believe that the pilot is the person responsible, how can all pilots have an influence on the maintenance of the aircraft, of the runways, and even of the standards to which the new pilots are taught? These and other facets of our sport can be verified and checked through an organised audit of the safety of the operation, of the club organisation perhaps, and of the many activities that go on at a club. We may have just had a "good" year, insurance claims-wise but overall, accident rates in gliding are not good, and the record is spotty. Is this because of a poor attitude generally within clubs, or is it because of long winter layoffs? Is it due to relaxing standards "enforced" by Chief Flying Instructors and by the club executives through the CFI? Perhaps it is a combination of some of these factors.
On the basis that we can improve, whatever the current reasons for our incidents and accidents, it is suggested that an internal safety audit within your club will help.
The following is an outline of the audit. The safety audit check list itself is presented here as a starting point for you to use and to build on. If your club decides to use this it is strongly recommended that you keep a copy signed and dated, and keep it in a safe place.
It is suggested that an audit at a club would be carried out by not less than two people, one of whom might be a member of another club, or perhaps someone familiar with the audit concept but who is not necessarily a glider pilot. They would look at the various aspects of the operation, providing assistance to each
other and receiving assistance from other members as needed. They would review the flying operation together with the Chief Flying Instructor for example.
If an "outsider" is giving assistance, the audit would best be done during normal club flying so that the "normal" mode of operation would be seen. As they visited the different areas of the club, the safety equipment and general layout of the hangars, tie-downs, etc., would be viewed. The run- ways and their approaches would be given close attention (I suggest this because the landing phase of flight is the most likely time for incidents to occur!)
They would discuss the club's future plans as regards glider acquisition, if any, and long-range plans which might impact on safety. The training program would be discussed not only with the Chief Flying Instructor but with others as the opportunity arose. A suitably qualified outsider such as a member of the Flight Training and Safety Committee could take a flight or two with recently soloed pilots, for example, and would use this to judge the current state of the club's training and what makes the club tick. Any feedback would be given later directly to the Chief Flying Instructor.
If therefore you would like assistance from the Association, please contact the National Office and suitable arrangements will be made.
NOTES FOR CARRYING OUT A SAFETY AUDIT
The purpose of a safety audit is not new. Here it is presented as an opportunity to go over with club personnel as many aspects of the club's operations as are thought needed, to compare how the club operates, and to define whether the club meets minimum standards defined by the Association for member clubs or for clubs wishing to become members. Suitably chosen "auditors" could carry out the checks with club personnel. Suitable people would need to have experience in flying operations and possibly in engineering, for example aircraft maintenance.
Before a safety audit at a club, the audit schedule or check list would be discussed within the club or by the club's directors as needed. Sections could be completed at any time before an arranged visit, or completed during the visit.
Organisation
Under this heading the club's constitution would be looked at, for example, to look at job descriptions of the club officials such as the Chief Flying Instructor (CFI) and Safety Officer, and to review flying rules and how these are dissemminated; to look at training records such as log book or record card use, appointment or election of CFI and Safety Officer (who are the current holders of the positions?), instructor committee meetings, etc. Publicity, including sending material to soaring magazines such as 'FreeFlight' and 'Soaring', might be included. Anything else?
Insurance
Is club insured? How eg. group, through the Association, or individual? If not what are the arrangements for liability, and are passengers insured? Is field and building insurance included? What checks for private owners insurance, and does the club specify minimums for hull and liability?
Flying Operation
Communications with flight line and in the case of winch operations, with the winch. What system is used, eg telephone, radio, or driving? Is radio used for winch launching, if so is a separate frequency used than the in-air freq? Emergency stop to winch.... what is used if regular system fails?
Accidents require some thought such as is there an accident reporting-procedure available, where? Do all instructors know what it is? What emergency equipment such as fire extinguishers and stretchers are there, and how often are they checked?
Are medical declarations for pilots held on file, are records of validity for others kept, are they up to date? Are licence renewal dates kept? For tug pilots also?
Airfield hazards should perhaps be a particular interest as accidents involving wires, grass, etc., have occured over the years, and we can become lax about them.
Instructional program. Here we would expect checks of the syllabus, is the Association scheme being followed, what training records are kept, can one instructor easily understand what level a student has reached, etc? Are instructor meetings held regularly, what checks are carried out by the Chief Flying Instructor to ensure adequate standards are maintained, etc?
Are any arrangements made for getting weather info? How is it dissemminated? Who shuts down the operation when minima are reached, winds get too strong or storms approach?
Cross-country flying. Are check sheets available for field selection training, for off-field landing checks, are pilots "authorised" and by whom prior to flying cross-country?
Are aerobatics taught, by whom and who may authorise them in club machines?
Spin training. What aircraft are used for this, and is it a generally taught lesson or only "when the student is nearly ready for solo"?
Sending pilots off for their first solo is a particularly responsible activity; there have been some fatalities on first solos over the years. What criteria are applied (weather, student fatigue, etc.), by whom, and who are authorised to send pilots solo within the club? Does your club require use of radio for first solos, for example, even under "receive only" operation? Give this serious thought.
Aircraft
Regular maintenance? How are defects handled and if necessary how is an a/c shown to be unserviceable to club members? Are all cockpit placards in good shape, are glider manuals or handbooks available to all pilots, where?
Do pilots report heavy landings, is this a generally known requirement? If fitted, are oxygen systems subject to regular servicing? Is some maintenance carried out by club members? Under what arrangements, etc?
Using the above notes the schedule below may be filled in.
SAFETY AUDIT - CLUB CHECKLIST
Item Requirement Club Comments
Reference documents:
Association Articles/Procedures
1 CLUB LEADERSHIP AND ORGANISATION
Safety Policy
1.1 Does the club have a general policy statement which includes a positive commitment to safety?
1.2 Is this statement posted or otherwise available to all members, for example in a rule book?
1.3 Does the club have a written safety program that it follows?
1.4 Does this program include items such as the following:
- safety training for pilots,
- planned facility inspections,
- accident/incident follow-up/analysis,
- emergency preparedness,
- club meetings (eg to discuss flying),
- training for tug pilots/winch operators,
- fire safety,
- public safety, etc.
1.5 Is club organised with a constitution and articles for winding up, etc.
1.6 Does club have an organisational manual or constitution that defines executive roles on safety policy, practices, etc?
Chief Flying Instructor (CFI) and Safety Officer (SO) Roles
1.7 How is CFI chosen or appointed?
Current CFI ............
1.8 Does the club have a Safety Officer and does he report to the directors/president?
Current S.O. ...........
1.9 What are their job descriptions and to whom do they report? Who has ultimate decision re flying operation? Use extra sheet if needed.
1.10 Are flying rules available to all members? How are they disseminated?
1.11 Are the rules permanently displayed in clubhouse or at the flight line?
General Club Organisation
1.12 Is publicity sent to local papers and National Magazine?
1.13 What is current club membership?
Male:
Female:
Over 60?:
Other members:
What are current fees?
Full member:
Student member:
Aerotow cost to 2000':
Glider rentals:
Any special details?
2 INSURANCE
2.1 Is club a member of Association Group Insurance scheme?
2.2 Is club insured? for a/c, for club facilities? For liability, how much in each case?
2.3 Is passenger insurance carried? Amount?
2.4 How are private owners covered re liability?
2.5 What requirements does club impose on private owners re insurance?
2.6 Is field and facility insurance carried? Amount?
3 FLYING OPERATIONS
3.1 What system is there to communicate with the flight line from club house? Describe.
3.2 For winching, what is the system to talk to the winch operator (not signalling system)?
3.3 What system is used to signal to winch operator during a launch?
3.4 If radio is used, what frequency?
3.5 Is this freq different from in-air freq? What is it?
3.6 What emergency system is used to stop winch if usual system, eg radio fails?
3.7 What emergency system is used to stop towplane if usual system, eg wing runner fails to signal STOP after "all out" signal?
4 ACCIDENTS
4.1 Are accident procedures available for use at club? And do all pilots have ready access to them?
4.2 Are accident reporting procedures available?
4.3 Do all instructors know where they are and what they contain?
4.4 What emergency equipment is available? At the flight line? At the refuelling point? And at the winch?
4.5 Is safety equipment checked, how often?
4.6 Do the local ambulance drivers know how to find the field, and to access it? And fire-fighters?
4.7 Does club encourage pilots to discuss incidents/accidents, and report them to the national body, through the Flight Training and Safety Committee?
4.8 What action is taken following an incident to investigate root cause?
4.9 What action is taken following an incident to prevent recurrence?
4.10 What action is taken following an accident to investigate root cause?
4.11 What action is taken following an accident to prevent recurrence?
(Accident = injury and cost; incident = no injury or cost but greater or lesser potential for accident if causes, etc. not addressed and preventative measures adopted)
5 LICENSING DATA
5.1 Are medical data kept on pilots, such as medical declarations?
5.2 Are validity dates kept for pilot licences, medicals, etc, including tug pilots?
6 AIRFIELD HAZARDS
6.1 What approach hazards are there? (List for each runway)
6.2 What approach hazards could be removed?
6.3 What is slope of runway/does it affect approach judgement/aiming point?
6.4 Do gliders tend to land close to runway threshold because the runway is short?
6.5 Is runway wide enough for size of operation?
6.6 What hazards exist at runway edges? eg crops
6.7 Do crosswinds cause difficult conditions, eg due to turbulence/obstructions at sides of runways?
6.8 On which runways?
6.9 Is regular maintenance of runway(s) evident?
6.10 Are there any mobile hazards? eg. cattle, people
6.11 What prevents their access to active runways?
6.12 Are visitors restricted from entering flight line areas? By car and on foot? How?
7 INSTRUCTION
7.1 Is flying training according to an approved syllabus, eg. Soaring Association of Canada?
7.2 If not explain which is used.
7.3 What are ground school arrangements for club? In the winter? and summer?
7.4 What flying training records are kept? eg student log book (from Association)? or student progress card?
7.5 Can succeeding instructor follow the student's progress using above record adequately? If not, what makes it easy for an instructor to see what training exercises are outstandingor have been inadequately covered during training?
7.6 How often are instructor meetings held?
7.7 What was date of last instructors' meeting?
7.8 What safety items are discussed at such meetings?
7.9 What "checks" are done by CFI to ensure all instructors are teaching a standardised curriculum and to similar standards?
7.10 Is a duty pilot/duty instructor on duty?
7.11 Is a roster for the above published? Where is it posted?
7.12 Describe the club requirements for sending students solo.
7.13 What criteria are used to judge if student is ready for solo?
7.14 What criteria are used to judge if conditions, eg visibility, wind, fatigue, are suitable for a first solo?
7.15 Does club require radio (eg receive only) during first solo flights?
7.16 What briefings are given to tug pilot or winch operator before first solos?
7.17 What intermediate/advanced training is offered post-solo, eg for the new bronze badge?
7.18 And what records are kept of this?
7.19 Are check lists (cards) available for type-conversions and cross-country briefings? If not, how are these covered and recorded?
7.20 Are dual checks required for all members annually? How many?
7.21 Explain criteria for acceptable performance.
7.22 If no checks required, how does club CFI check competency of pilots?
7.23 Are all students taught to be spin competent before first solo?
7.24 If not when is the training given?
7.25 What aircraft are used for spin training?
7.26 Who gives spin training? eg Class I (senior) instructors only or all instructors?
7.27 Passenger carrying: what experience beyond licence is specified by club for carrying friends only?
- carrying third parties, i.e. people off the street?
7.28 What passenger carrying training and checks are required?
7.29 Who may give passenger-carrying training and checks?
8 WEATHER
8.1 Are arrangements made for weather forecasts?
8.2 How are these displayed/relayed to club pilots?
8.3 What weather minima are observed?
8.4 Who is responsible for ensuring club pilots are adhering to these?
8.5 Are inexperienced pilots limited from flying under adverse conditions, eg strongwinds?
8.6 How are they trained to handle these conditions?
8.7 Who is responsible for shutting down the club operations when conditions threaten safety?
9 CROSS-COUNTRY FLYING
9.1 Is off-field landing training given?
9.2 What field selection training is given prior to cross-country flying?
9.3 What field landing checks/flying checks are required before a first x-c flight?
9.4 Who are authorised to give such checks?
9.5 What requirements are specified before allowing x-c flights?
9.6 Are NOTAMS and other restrictions, eg local areas to avoid posted/known to pilots?
9.7 Are tie-down kits carried by club a/c?
9.8 Are they available for x-c flights?
9.9 If there is a controlled A/P close by, what notification is given regarding gliding operations when the club is active?
10 AEROBATICS
10.1 Are aerobatics taught? By whom?
10.2 What aircraft are used for aerobatic training?
10.3 Are aerobatics permitted in club a/c? If so, when and who authorises?
11 EQUIPMENT
Winch
11.1 Is regular maintenance done?
11.2 Is there a set operator training program?
11.3 What cable replacement policy is there? eg. number of launches or cable breaks?
11.4 What weak links are in use? Standard design or not, and what strengths?
11.5 How do pilots ensure correct link is used?
11.6 When was guillotine last checked?
11.7 Is winch grounded/anchored? How?
Parachutes
11.8 What is standard policy of club for use in single/two seaters?
11.9 How are club 'chutes stored?
11.10 What is packing program/history?
Seat Cushions
11.11 Is energy absorbing foam (EAF) specified for all seat cushions, and provided in club gliders?
11.12 Is this type of cushion material encouraged in private ships?
11.13 Is club and are members fully aware of benefits of EAF use in gliders?
11.14 If not currently used, what program is there to introduce EAF?
Seat Ballast
11.14 How is this provided in club a/c?
11.15 Can the ballast be properly secured in the cockpit so that it will not move under sudden deceleration, or -ve 'g'.
11.16 Are light-weight pilots specifically instructed on the dangers of not using it, and of inadequately securing it?
11.17 Is there a recommended minimum pilot weight suggested for inexperienced pilots?
12 AIRWORTHINESS
12.1 List club a/c here and give ages and hours of each, with estimate of annual hours.
12.2 Do all club gliders carry required documents? Are they up to date?
12.3 How does club ensure gliders with defects are not flown?
12.4 Are all cockpit placards in readable shape?
12.5 Are pre-takeoff and pre-landing check lists available in cockpits and legible?
12.6 Are gliders in good shape/clean, etc?
12.7 Are glider handbooks available to all members?
12.8 Are glider manuals available to all pilots?
12.9 Do pilots report unusual events such as heavy landings, excess 'g' loads, flight control anomalies?
12.10 Are pilots required to report these events?
12.11 Does the club encourage incident reporting?
12.12 Does this include aircraft defects?
12.13 Older club a/c. Due to their age are any special maintenance efforts made to ensure their continued safe operation?
12.14 If so, describe these.
12.15 Oxygen systems. What servicing is carried out on club equipment? How often?
12.16 What maintenance is carried out by club members and if so under what arrangements with qualified professionals?
13 FACILITIES
13.1 Are planned inspections carried out, eg on:
- hangars and associated equipment?
- tie downs,
- fuel storage equipment,
- roads and field?
- electrical equipment, incl. camping outlets?
13.2 What check lists are used for above?
13.3 How often? and when was last such inspection?
13.4 Are records kept of such inspections?
14 FIRST AID
14.1 Are tel numbers, addresses for emergency services listed? In readily accessible place?
14.2 What percantage of members are first aiders, MDs?
14.3 Is a current list available and posted?
14.4 What first aid equipment is readily to hand?
14.5 When were they last checked?
15 CERTIFICATION
This audit was carried out between ........................ and
................. (dates)
by the following club member(s): ..............................
..............................
..............................
..............................
print name signed date
and by the following non-member(s)...........................
..............................
..............................
..............................
print name signed date
..............................
President of club signed date
SOARING ASSOCIATION OF CANADA 111, 1090
Ambleside Drive, Ottawa,
Ontario, K2B 8G7
First Issue 1992 April
Second issue 1993 April
Third issue 1995 June
US Dept of Transport
AC 67-2
May 1974
PILOT MENTAL AND PHYSICAL PERFORMANCE
David Edwards
Iowa State university
ISBN 0 8138 0452 3
HUMAN FACTORS IN FLIGHT
Frank H Hawkins
Gower Technical Press 1987
ISBN 0-291-39739-5
GLIDING SAFELY
Derek Piggot
A&C Black 1991
ISBN 0-7136-3397-2
THE SAFETY CORNER
Miles Cloverdale (?)
SSA
(A collection of articles from the Safety Corner column of Soaring magazine. A collection of some of the best from the past.)
END OF FAQ