Fatigue is something that isn't talked about very much in aviation circles. In fact, it's one of those nonquantifiable factors that, if it left some sort of traceable residue during autopsies, would probably come out as a contributing factor to a lot of accidents. Instead, it is hidden as an accident cause because it is lumped into that well-known category, "pilot error." Yes, its true that the pilot made a mistake either in skill or judgment, but we'll never know for sure how much of a role fatigue played in that mistake.
Fatigue comes in many flavors, and simply feeling tired is one of the lesser forms. In fact, you can be tired and still not be fatigued. More often - and more dangerous - you can be fatigued without even realizing it.
When it comes to flying, fatigue has to do with the way your mental processes are functioning. You could have been digging ditches all day, which has left you bone tired, but your brain may be nearly unscathed because it was off doing something else while your muscles were busy moving dirt. By the same token, you could have been sitting behind a desk, hammering away on your computer, fielding phone calls and fending off management, and never have moved a muscle for hours-but still leave the office with your brain bearing a great resemblance to Silly Putty. Never forget that flying is first, last, and always an intellectual pursuit, not a physical one. That makes mental exhaustion enemy number one.
To make the entire fatigue issue that much more critical, flying itself is tiring, especially while you are still in the learning-to-fly mode. For one thing, the cockpit environment is both noisy and intense. For students, everything that makes flying tiring - noise, vibration, cramped quarters-is amplified by the fact that everything is so new that even the simplest tasks require continuous, intense concentration. So, if you were a little below par when you got into the cockpit, your performance will drift downhill even faster than normal.
The moral is, if your brain isn't up to coping with everything that's likely to be thrown at it, don't get in the cockpit, either as a student or as pilot in command. In fact, it's always a good idea to run the I'M SAFE checklist on yourself by determining that you are free of illness, medication, stress, alcohol, fatigue, or emotional upset before embarking on every flight.
As a student, your ability to learn is tightly coupled to your fatigue level. Tired brains simply don't absorb information very well. Tired brains can't perform, and the more they try, the more tired they get. and when the brain stops performing, the body is sure to follow.
However, even if you get into the cockpit with a set of fresh batteries plugged into the old brain cells, it's almost guaranteed that in an hour or so your brain is going to start to get tired and give out on you. You will find yourself unable to perform tasks that you've done well earlier in the lesson. The manner in which your brain gives out is something that bears further discussion.
Everyone fatigues. That's a fact of life. The speed at which someone fatigues and the manner in which fatigue affects him or her, however, varies greatly from individual to individual. To find out how you fatigue and what your personal warning signs are, pay attention to how long it takes for you to become something less than a stellar performer. Once you realize that your performance is slipping, think back to the first indications that you were getting too tired to fly well.
Among other things, think about your last lesson and how your brain was working at the end, as compared to the beginning. Were you aware of everything that was going on around you and were you doing what you'd consider to be your best work? Or did you see yourself sliding downhill? Did you feel fatigued? And how long was the flight?
It's not just up to the instructor to decide how long training flights are. The student also should be aware of his or her limitations and be ready to step in and say, "Let's make this the last landing, my brain is starting to smoke."
Students and pilots generally fatigue along one of two general profiles. One type of person will begin getting tired and his performance will slowly go downhill as individual tasks begin to get sloppy or are dispensed with altogether. Maybe the airspeed, which at the beginning of the lesson was steady as concrete at 85 knots, begins to drift erratically between 82 kt and 88 kt. Or maybe rudder control gets weak and the inclinometer ball starts floating around as you slip and skid through turns. In general, starting at about 0.7 hours, this individual's performance gradually deteriorates, getting worse and worse the longer he or she is in the air.
The other profile is the person who is absolutely aces right up to the point that their brain signals it has had enough and the "off" flags come up in their eyes. This type of person has the fatigue curve of a NiCad battery. These folks are terrific performers on one landing pattern and are unable to find the runway with a white cane on the next.
It is important for both the instructor and the student to know how the brain fatigues so that the lesson length can be adjusted accordingly. An astute instructor has his or her antennae up from the first lesson to pick up cues as to when the student is approaching burnout. The instructor should be careful not to exceed that time.
For either an instructor or a student to push the lesson past the point at which fatigue has begun to set in is not only counterproductive but can actually damage the learning process. Besides the fact that money and time are being wasted trying to cram more knowledge into a brain that is already temporarily saturated, flying too long can easily set back the student's progress and confidence.
Once a brain starts to fade, you can forget about improving on whatever has gone before in that lesson. Going one touch and go past that point means that the next landings won't be as good, regardless of how hard the student tries. When this happens, all the student sees is that he is expending more energy but doing worse. This is where frustration sets in.
Ideally, every lesson will end on an up note with the student doing better at the end than at the beginning. After lessons like that, the student whistles a happy tune all the way home and can hardly wait to return. Reality being what it is, however, that isn't always the case, simply because no one improves with every lesson. However, pushing a lesson so long that fatigue takes hold almost guarantees that the lesson will end on a down note and the student will go home whimpering the blues. A student who goes home in a funk is a student who won't be all that fired up about coming back out to the airport to humiliate himself again. This is not constructive instruction.
Quite often some type of distraction is coupled with, and aggravating, the fatigue, and often this distraction is something that has nothing to do with airplanes. Most of the time the distracting thought process can be traced to some very common sources. Personal finances and relationship problems undoubtedly run neck and neck for number one with job/career difficulties coming in right behind. Then there is the question of airborne distractions. These can range from having an instructor with a world-class case of bad breath to a tower operator who has a voice resembling your ex-wife's, and it angers you every time she tells you to do something.
The question of how to handle external distractions is both tough and easy to answer. It is tough to answer because different people deal with non-aviation distractions in different ways so there is no single solution. A great many people get into aviation in the first place because it requires them to focus in such a way that it forces all the extraneous thoughts out of their minds. The instant they crawl into the cockpit and strap in, their mind is in airplane mode, and ex-wives, bosses, clogged bathroom drains, and all the other distracting influences in life disappear. The airplane is their escape.
Other pilots are just the opposite. They can't get bills, sick dogs, dented cars, and the like out of their minds no matter how hard they try. Only part of their brain is focused on the airplane, and that part is pushed to the max to perform so it wears out quickly. The result is almost always an unsatisfactory experience for student and instructor alike.
In the case where distractions are part of a student's life, it's important to recognize the effect that they can have on the learning process. Far too often a student will come out to the airport and have a lousy flight. Only afterward will he admit, "...yeah, well, I had other things on my mind." That's the kind of conversation that should be held before getting into the airplane. In fact, if you're a student, you should do some personal evaluating before you head for the airport.
All students should make an effort to put themselves into airplane-mode as they are leaving home or work and heading for the airport. Don't wait until you're strapping into the airplane to begin thinking about flying. Get your brain up to speed on the way to the field. This serves the purpose of getting your thought processes spooled up, giving you the opportunity to mentally review your last lesson and your plans for the upcoming one, and letting you start poking around inside yourself to ascertain that all systems actually are go for the flight.
Stand back inside your own brain for a few minutes and watch yourself as you try to get into airplane mode. Are you picturing the airplane and starting to slide into the groove? Or are images of unpaid bills, the CEO of the company you're trying to buy, or your latest embarrassment clouding the image?
It's important to give yourself the once-over to make sure it really is a good idea to go flying. If there's any question at all, most often you'll be in one of those do-I-or-don't-I situations where the decision isn't that clear-cut. When that kind of thing occurs, let your instructor know right up front that your head may not be completely up for this flight. That way, if things start going into the toilet, you already have reached a mutually-agreed-upon decision to pull the plug with no hurt feelings.
At the same time, this is your opportunity to find out if you're one of those I'm-clearing-everything-out-of-my-head people who can shut out the world and focus on flying. About 50 percent of students can and the rest can't. Unfortunately, most don't know which half they are in until they try it.
The single most important fact is the simple knowledge that fatigue is a quiet, colorless, tasteless killer that starts eating away, first at your skills and second at your safety. Just know that it's there and always give yourself plenty of margin for safety. Be sure to always quit flying while you still have a little energy left in the old brain batteries.
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