Budd Davisson, Flight Training, April 2000

Fatigue: Knowing When Flying Isn't Such a Great Idea

It's been a really hard day. The folks at the office were all on your case, even though you showed up an hour before everyone else so you could leave early to take a flying lesson. They didn't mean anything by it, it was just one of those days and it left you feeling a little dull. Not quite with it. But the flight is scheduled. So somehow you'll muddle through. After all, you're just a little tired, that's all.

This, in case you don't recognize it, is a mistake in the making. Since you're going out for a lesson, it probably won't be a mistake that could lead to fatal consequences, but flying when you're pooped is a mistake, for a lot of different reasons. Among other things, flying itself is fatiguing.

Fatigue is something that isn't talked about very much in aviation circles. In fact, it's one of those unquantifiable 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. As it is now, it is hidden because it is lumped into that well known category, "pilot error." Yes, the pilot made a mistake either in skill or judgment, but we'll never know for sure how much of a role was played by fatigue.

Fatigue takes on 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, you'll be fatigued and not even know 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 your brain was off doing something else while your muscles were moving dirt. By the same token, you could be sitting behind a desk, hammering away on you computer, fielding phone calls and fending off management and never move a muscle, but 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.

Fatigue takes on many flavors and simply feeling tired is one of the lesser forms.

To make the entire fatigue issue that much more critical, flying itself can be terribly fatiguing, especially while still in learning to fly mode. For one thing, the cockpit environment is both noisy and intense, and it consumes brain neurons like they are candy. Every fatiguing aspect of flying is amplified even further for a student because everything is so new, it requires 110% of your brain just to keep up, much less understand. So, if you were a little below par when you got in the cockpit, you'll drift downhill even faster than normal.

The moral to the above is, don't get in the cockpit, either as a student or as a pilot, if your brain isn't up to coping with everything that's likely to be thrown at it.

As a student, your ability to learn is very much coupled to your fatigue level. Tired brains don't absorb. Tired brains can't perform and the more they try, the tireder they get. 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, give or take a little, your brain is going to start to give out. The manner in which it gives out is something that bears discussion.

Everyone fatigues. That's a fact. The speed at which someone fatigues and the manner the fatigue effects them, however, varies greatly from individual to individual. Both of these factors, the time it takes to fatigue and the clues that fatigue is eating into your performance, absolutely must be noted by the instructor beginning with lesson one. If he's not doing that then the task falls to you, the student: pay attention to how long it takes for you to become something less than a stellar performer.

The generic "flying lesson" is 1.0 hours. Schools that are Hobbs-meter-driven, may even run the clock up to 1.2 or 1.3 hrs. This isn't good unless it is constantly coupled to a critical question; is the student still learning? A parallel question would be "how do you know if the student is still learning?"

Students/pilots fatigue along two general profiles. One extreme will begin getting tired and their performance will slowly go down hill as individual tasks begin to get sloppy or are gone all together. Maybe the airspeed, which at the beginning of the lesson was steady as concrete at 85 knots, begins to drift erratically between 82 knots and 88 knots. Or maybe rudder control gets weak and the ball starts floating around. In general, starting at about .7 hours, this individual gradually gets worse and worse the longer he or she is in the air.

The other extreme is the person who is absolutely aces right up to the point their brain signals it has had enough and the "off" flags come up in their eyes. They have the fatigue curve of a NiCad battery. They are terrific on one landing pattern and unable to find the runway with a white cane the next. It is important both the instructor and the student know how the brain which is supposed to be learning (the student) fatigues so 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 burn-out and that instructor is careful not to exceed that time.

...don't get in the cockpit, either as a student or as a pilot, if your brain isn't up to coping with everything that's likely to be thrown at it.

For either an instructor or a student to push the lesson past the point that 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 the student back. For one thing, once a brain starts to fade you can forget about improving on what ever has gone before in that lesson. Going one touch and go past that which the brain can readily absorb means the next landings will be downhill regardless of how hard the student tries. When this happens, and the student doesn't recognize the signs of fatigue, all he sees is that he is expending more energy but doing worse. This is where apprehension raises its ugly head and 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 every lesson. Everyone has plateaus. However, pushing a lesson so long that fatigue takes hold almost guarantees 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 the distraction is something which has nothing to do with airplanes. Most of the time the distractive 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 every where from having an instructor with a world class case of body odor 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 answer. A great many people get into aviation 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 into airplane-mode and ex-wives, bosses, clogged bathroom drains and all the other distractive influences in life disappear. The airplane is their escape.

Other pilots are just the opposite. They can't get bills, sick dogs, dented cars, etc., out of their minds. Only part of their brain is focused on the airplane and that is pushed to the max to perform 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 and quantify the effect they can have on the learning process. For one thing, simply recognizing that distractions can have an effect is a major step towards a cure. Far too often a student will come out to the airport, fly a lousy flight and then, afterwards when being debriefed by the instructor admit, "...yeah, well I had other things on my mind." That's the kind of conversation that should be held before getting in the airplane. In fact, if you're a student, you should do some personal evaluating before you even head for the airport.

Every student should make an effort to put themselves into airplane-mode as they are leaving for the airport. Don't wait until you're strapping in to begin thinking about flying. Get your brain up to speed on the way to the aerodrome. This serves the dual purpose of not only getting your thought processes spooled up, but lets you start poking around inside yourself to ascertain that all systems actually are go.

Among other things, think back to the last lesson and how your brain was working at the end, as compared to the beginning. Were you aware of everything and were you doing what you'd consider to be your best work? Or did you see yourself siding downhill? Did you feel fatigued? And how long was the flight? It's not just up to the instructor to decide how long the flights are. The students should step in and say, "Let's make this the last one, my brain is starting to smoke."

The student should step in and say, "Let's make this the last one, my brain is starting to smoke."

Stand back inside your own brain 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 interrupting and clouding the image? When you reach to start the car, do you find your hand headed towards the radio rather than the key? Did you almost rear-end that pick-up at the stop light?

It's important to give yourself the close once over to make sure it really is a good idea to go flying. 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 your head may not be up for this flight. That way, if things start going into the toilet, you already have a mutually agreed upon decision to pull the plug with no one feeling hurt.

At the same time, this is where you find out if you're one of those I'm-clearing-everything-out-of-my-head guys who can shut out the world and focus on flying. About 50% 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 secondly at your safety. Just know it's there and give yourself plenty of margin. Always quit flying while you still have a little energy left in the old brain batteries.