When the pilot woke up, he was soaking wet, and cold rain was pouring down on him. He couldnt see out of one eye. His leg and arm were killing him. There were pieces of something in his mouth. He took them out. They were two of his front teeth.
It was about dawn. As he looked around, things were still fuzzy, but he realized that he was in his Comanche. The windshield was broken out, the cabin door was open, and they were sitting in a muddy cornfield.
Six months later the pilot, who also was a flight instructor, was telling the story to a group of people at the airport. How hed changed. His face was heavily scarred now, and he needed a cane to get around.
He was a poignant reminder that sometimes we tend to push the limits of our personal physiological envelope too far. Often, we are lucky and get away with it. And there are the times when we cant pull it off.
The unfortunate instructor continued his story of how he had come to wake up in a muddy Texas cornfield.
He said that when he came to, he looked out on the wing, and saw that his friend had made it that far, but had apparently passed out.
He said it took all his strength to struggle out of the Comanche cabin. He was glad to see his friend was still breathing, but couldnt get him to wake up. Then, as he partly crawled and partly limped through the mud toward the lights of a farmhouse, it all began to come back to him. Well, most of the flight, anyway.
The two men had flown to Florida the day before to take part in a cross-country air race. After the race, they had stayed for a barbecue and finally started home in the late afternoon.
They flew back to south Texas the same night, on the go for 20 hours without sleep. When they arrived at the VOR at about 2 a.m., there was a stratus deck below them, with a ceiling of about 1,500 feet and visibility of one to two miles.
They requested an ILS to a large airport nearby. Once through the cloud layer, they canceled IFR and headed for their home base, an uncontrolled field, about 10 miles away. They both remember seeing the runway lights as they entered a close-in downwind leg. The pilot said they were about to turn base when he remarked to his friend that it was nice to be home. That was the last thing he remembered. His friend didnt even remember that.
The pilot brought the story to a group of flight instructors with a sincere desire to know what they thought of it, hoping that maybe someone would have some clue as to why the flight went bad.
He was absolutely certain that the altimeter setting was correct. Both pilots remembered the setting – and putting it in the Kollsman window.
The flight instructor group included pilots with many different layers of experience. There were retired airline pilots, retired Air Force pilots, corporate pilots, a number of active-duty military pilots, an air traffic control specialist, a couple of FAA-designated pilot examiners and a few instructors whose ink was still drying on their certificates.
The arguments ranged far and wide, and initially most of the group concluded that carbon monoxide poisoning from the aircraft heater was the most likely cause. The two aboard the aircraft, however, said the flight had been made on a warm night and they hadnt used the heater. Besides, the heater had been carefully checked for leaks during the last annual inspection, about two weeks before the flight.
Finally, one of the designated pilot examiners and an Air Force officer from the Training Command gave their joint opinion: Being sleep-deprived for a long period of time leads to a condition called micro-sleep, where the brain shuts down for just a few seconds. Micro-sleep at the wrong time may be at least partly to blame in over half of the accidents that occur.
The two pilots had both relaxed once they had the runway lights in sight and dropped into micro-sleep. The Comanche flew itself to a lucky splash-down, in the muddy corn field. Of course, this conclusion wasnt official in any way, but it fit the pattern of other accidents that have occurred under similar circumstances.
Lack of sleep has been shown to be involved with five internationally famous disasters: the nuclear accident at Chernobyl, the near meltdown at Three Mile Island, the oil spill by the Exxon Valdez, the collision of two 747s at Tenerife, and the loss of the space shuttle Challenger. All were tied to people who had too little sleep and, as a result, made some big mistakes.
Let Me Sleep On It
Psychologically and physically, humans need sleep to repair and revive their energy. Some researchers have questioned whether the human sleep/wake cycle can really handle life in the fast lane. While the average adult slept 9 hours per night 100 years ago, many adults now find it almost impossible to maintain a regular schedule of even 6 to 8 hours of sleep per night.
A recent article in The Wall Street Journal reported that fatigue costs U.S. businesses about $70 billion a year in reduced productivity. And in the United States about 6,500 fatal automobile accidents a year can be blamed on drivers falling asleep at the wheel.
At Brooks Air Force Base in San Antonio, Texas, the Department of Physiology does much of the Air Forces research into human factors in military aviation, specializing in fatigue, spatial disorientation, acceleration forces and crew resource management.
Lack of sleep and the resulting fatigue are the big problems, says Lt. Col. Rick Evans, head of the department. About half of the mishaps in military aviation that have a human factors connection – poor thinking patterns and slow reactions to life-threatening situations – are a direct result of fatigue.
The most insidious problem is known as sleep debt. The average 30- to 50-year-old adult needs seven to eight hours of sleep per day. So if you get six hours sleep one night, you put yourself into a two-hour sleep debt. If you get six hours of sleep the next night again, you put yourself into two more hours of sleep debt.
Like any kind of debt, you can get by for a while, but eventually it has to be paid. Research has shown that pilots performance deteriorates when they are experiencing additive sleep loss prior to testing.
A study of mishaps filed with the NASA Reporting System investigated whether the errors were the result of the pilot not being attentive to the task at hand. Researchers wanted to know if the pilots saw the right thing to do but didnt do it because of fatigue. Then they went deeper into case histories. All of the pilots admitted to routinely getting less than six hours of sleep per night.
Of course, many pilots feel that they can motivate themselves through a sleepy situation, Evans points out. And while some people can in some situations, the protection is almost always short-lived, he says.
Sleeping May Not Be Enough
But even people who think theyre getting enough sleep can find themselves running from fatigue.
Stress, lack of exercise, poor nutrition and a heavy workload all contribute to failure to operate at peak performance.
And then there is the problem of jet lag. Even in singles and light twins, air transportation is fast enough to travel over a number of time zones in a single day. What happens then is that our internal clock is out of sync with the local time.
Most people who cross time zones try to get adjusted immediately to the new time. But adjusting circadian rhythms isnt that easy. The daylight level may be different and eating and sleeping times are different.
As a rule-of-thumb, it will take one full day to get your body clock adjusted for each time zone you cross. Two zones will take two days to feel comfortable again. On an air carrier flight, you might cross through eight time zones, which would be about the same as changing your work shift eight hours, with no time off in between.
Your body has a number of daily physical cycles, and all catch up with local time at different rates. The heart rate cycle adjusts at about 60 minutes a day. Body temperature adjusts at approximately 40 minutes a day; the urinary rhythm readjusts at about 90 minutes a day, and the steroid cycle only adjusts at 30 minutes per day. So, if you cross three time zones, it will take your heart cycle three days to adjust, body temperature four days, urinary cycle two days and steroid cycle six days to accommodate the new local time.
Sleeping can be difficult when the body is out of adjustment and what sleep you get is often broken and not too restful. For many pilots, this is a way of life.
Corporate pilots often find themselves in this fix, waiting all day in the pilots lounge until its time to take the bosses back to Detroit, then finding out at 1 a.m. that the executives need to be in Portland, Ore., as soon as possible.
The NTSB files contain a number of accidents involving corporate aircraft that fit this combination of stress and fatigue. There are really only two things that you can do about it: talk them out of it or get some sleep while you are waiting. Most pilot lounges have facilities for crews to get some rest while on call.
To improve rest on the road:
• Try combat naps whenever you have a chance to rest. Even 15 minutes of sleep is better than another cup of coffee.
• Sleep eight hours a day, even if it is in two-hour increments.
• Dont use the bed in the hotel as an office, littered with paperwork and a computer. It delays your sleep when you need to find another place for all of that stuff.
• Relax. Nuff said.
• Get some light exercise. Moderate walking is a good start. Some motels have small gyms and most have swimming pools.
• Watch what you eat, including your consumption of junk food, coffee and chocolate.
• If your room is in a noisy area, tune the TV to a blank channel and let the white noise block out other noise. Setting the air conditioner to fan may do the same trick.
Better Living Through Chemistry – Not
If you plan to get some quality sleep, alcohol wont help at all. There is a popular belief that a drink or two will help you get to sleep quicker. And it will. The problem is that it interferes with the three stages of sleep.
In the first stage, the body slows down into a dream phase, which lasts for about 10 minutes. The second stage is a deeper sleep (where the body rebuilds strength), which lasts from 15 to 30 minutes. The third stage lasts about an hour, which is deep sleep, and provides the mental rest.
Alcohol interferes with the length of the first stage and breaks the natural sleep cycle. As a result you dont get the full rest you need.
Sleeping pills also dont produce normal sleep, and doctors advise against continuous use anyway. There are a number of herbal sleep aids on the market now, including melatonin. Several have come under the watchful eye of the Food and Drug Administration, but there is little scientific research at this point that demonstrates how each affects sleep cycles.
To stay awake while flying long hours, some pilots resort to uppers despite their considerable side effects. From a purely technical standpoint, your medical certificate is invalid if your personal health and awareness is not exactly the same as when you received your physical examination by the medical examiner. From a more practical standpoint, however, remember that even the most powerful stimulant can only postpone sleep at best. They cant always restore alertness nor can they keep you awake when your body finally calls it quits.
There are a number of studies that show tired people perform like drunks. For example, someone whos been awake for 17 hours will perform about the same as a person with 0.05 blood alcohol level. If you have been awake 24 hours, you are practically legally drunk.
Flying with a serious sleep debt is somewhere in-between. You will tend to think that you are in better shape than you are. You may think you are alert, but your actual performance will be poor. An Air Force study of pilots with serious sleep debt showed that 22 percent of those tested in a flight simulator fell victim to micro sleep from the final approach fix inbound to the field.
Recognize that sleep problems are serious. They can slowly undermine your health, or kill you very fast in an asleep-at-the-controls accident. The solution is a survival skill that you can learn. Fix the problem yourself; tailor your sleep management to your own needs.
One way to check what amount of sleep is best for you is to try a sleep experiment. For one week, go to sleep at least eight hours before you need to get up. If you wake up rested and ready to go, and feel that way throughout the day, youve gotten enough sleep.
If eight hours doesnt work, try changing the amount of sleep by adding to or subtracting from your previous sleep time. Change your sleep by 15 to 30 minutes at a time, and hold the sleep pattern for a week. Eventually youll discover the amount of sleep that works best for you.
Fatigue is physiological. If you lose sleep, youll be tired. That cant be prevented nor avoided. Long term, you cant work through it and you cant cover it up with caffeine or drugs.
If you have problems sleeping, remove the things that prevent sleep, like noise, heavy meals and worries. Then leave the rest of it up to the wisdom of your body. It is very ingenious, and it knows how to sleep.
Recognize that sleep problems are serious. They can grind your health down slowly, or kill you quickly in asleep-at-the-controls accidents. Solving sleep problems is a survival skill that all pilots need to learn.
Also With This Article
Click here to view “Long Workdays and Pilot Fatigue.”
Click here to view “Some Rules for Napping.”
-by Raymond Leis
Raymond Leis is a CFII and ATP with more than 23,000 hours.