Plane & Pilot
Tuesday, July 9, 2013

Pilot Fatigue

Are you safe to fly?

Most often, when we use the term "fatigue" in aviation circles, it refers to the airplane's fatigue life. Airframes get tired, eventually reaching the point that they're dangerous. The exact same thing could be said about the pilot's airframe. A pilot can easily reach a level of fatigue that he's no longer safe to fly. What makes it difficult, however, is that he may not even know he's getting fatigued. Then, when this is mixed with any kind of distraction, a pilot becomes a danger to himself, his passengers and those around him.

Actually, fatigue and distraction are two different subjects and often have their roots outside of the cockpit. However, they become intertwined, once the cockpit door is closed, and their effects are hard to separate. So, let's talk about them individually, then address how to tell when we're about to step over the threshold and do something stupid, like flying when we shouldn't be.

Fatigue Defined
First of all, fatigue is more than being tired, even though we often use the terms interchangeably. By far the biggest difference is that "tired" can readily be felt. We know for a fact when we're tired because we have an urge to curl up in some warm cozy place and catch a few "z's". It's hard to be tired and not know it. We're droopy. And, in extreme cases, maybe a little dopey.

Sometimes "fatigue" can have the same symptoms. That's when the effects are so extreme we say we're "bone tired:" It's as if our body is sagging. In fact, most of us get a feeling that our face is sagging as a signal that we're past being tired and are well into being fatigued. However, long before our body is sending out warning signals, our brain is already feeling the effects of fatigue. Our body can feel just fine, when our brain is anything but fine.

There are obviously two different forms of fatigue—mental and physical—and one can easily exist without the other. For example, let's say that for some reason we're digging a ditch by hand. We spend hours busting our back while hoisting dirt out of a hole. Our body is taking a real beating. However, during the entire process, our brain is barely engaged. In fact, part of our brain may be snoozing or reliving a favorite movie. The amount of our brain that's involved in guiding the spade and correctly depositing the dirt alongside the ditch is small. So when the ditch is finished, our body is spent, but our brain is still ready to rock and roll. It's not unlike the flight to get a $200 hamburger on a bell-clear, perfectly smooth day: We know where we're going, but nothing about the flight is remotely challenging, so our brain is minimally challenged.


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