We don't always give a lot of thought to what will happen in the "unlikely event" of pilot incapacitation in the multi-person crew aircraft, but there's a real possibility it can happen at any time. On a flight about 20 years ago, my copilot advised me on final approach that he "really wasn't feeling very well." I took control of the aircraft and we had an uneventful landing and taxi, but his condition got progressively worse. By the time all the passengers had deplaned, he felt so ill that he could not get off the plane under his own power. We had paramedics carry him off on a stretcher, and he was rushed to the hospital, where he required three IV bottles to treat him for food poisoning. Just like in the movies, it had been the fish! We had been lucky that day: if he had eaten his crew meal fifteen minutes earlier, his total incapacitation would have occurred at the most critical portion of the flight.

Though we often first think of the "movie version", there are really several levels of pilot incapacitation. The most obvious, of course, is overt incapacitation, such as my copilot's, where the pilot is clearly unable to perform his or her duties due to a physical inability. Examples of this range from heart attack, seizure, and food poisoning to a kidney stone attack. There are numerous documented cases of in-flight occurrences of these illnesses.

Recognizing this type of incapacitation is easy. There are overt, clear indications that the pilot is in distress. The most important action for the other pilot to take is to FLY THE AIRCRAFT. Next, get the other pilot away from the controls, to prevent inadvertent flight control inputs. This may require the assistance of another flight deck crewmember, a flight attendant or a deadheading crewmember. Once the disabled pilot is away from his station, you can try to obtain medical or first-aid assistance on board and with MedLink, if available. Obviously, depending on the nature of the distress, you may need to land immediately rather than continue to your destination. You may be able to fill the disabled pilot's seat with another pilot, perhaps a deadheading pilot if the crew has not been augmented. Even if that pilot is not current or rated on your aircraft, he or she can be of assistance reading checklists, lowering the gear, and, in general, taking some of the load off the flying pilot. If there is no available pilot, you can even use a flight attendant to read checklists and reduce the load on the pilot flying.Not so obvious, and perhaps more dangerous, is subtle incapacitation, in which the pilot is unable to perform his duties, but there is no marked difference in his appearance. This could be something as transitory as the pilot day-dreaming to something as serious as his suffering a loss of consciousness with his eyes open. There have been cases of this type of incapacitation due to everything from fatigue and hypoglycemia to brain tumors.Depending on your flight schedule, fatigue and hypoglycemia are very real possibilities. If you had a hard time getting to sleep because of the boisterous teenagers down the hall in your hotel, you may be operating at less than optimum. (Naturally, you're FAR 117-okay, right?). If you skip breakfast to try to get every minute of sleep you can, you're setting yourself up for an additional problem: hypoglycemia. When you grab a donut with your coffee on the way to the airport, you've completed the recipe. The sugar in the donut initially gives you a rush of energy and helps wake you up. Your body's energy-regulating mechanism, sensing this increase in blood sugar level, thinks you've just had a big breakfast, and signals your pancreas to secrete insulin, a lot of insulin, to maintain the proper level of blood sugar. When your blood sugar level drops after the short energy fix you got from the donut, you now have an excess of insulin in your blood, and get the "post sugar lows", actually insulin shock. You may have felt great with the burst of energy the donut gave you for takeoff, but now it's payback time later, maybe over the outer marker!Clearly, the most difficult aspect of dealing with subtle incapacitation is in recognizing it. It's essential in a crew aircraft that each pilot be able to recognize when the other pilot is not performing at the expected level.One way is strict adherence to Standard Operating Procedures (SOPs), so that any deviation becomes immediately obvious to the other pilot. Those Standard Callouts are in the flight manual for a reason. If the other pilot does not respond with the proper callout, you can be alerted to at least look over to see if he/she is all right. It could be simply a forgotten response, or it might be a case of subtle incapacitation. Some years ago, at another carrier, the use of callouts alerted a crew that the pilot at the controls of a B727 had suffered a heart attack, which had gone unnoticed on an approach! Apparently the power setting and trim had been so well established that the plane flew right down the glide slope, on airspeed and on course.Like many other areas of flying, the job's not finished until the paperwork is complete. In this case, NTSB Part 830 requires a report if any crewmember becomes ill and cannot perform his duties. And, naturally, your boss needs to know about it.

Incapacitation, either subtle or overt, is a fairly unlikely occurrence, but can have very serious consequences. The key to successfully handling it, as with other in-flight emergencies and irregularities, is preparation.