Pilot incapacitation refers to any condition where a pilot is unable to perform their flight duties due to a medical or physical issue. This can be sudden, as in the case of a heart attack or stroke, or gradual, as in the case of fatigue or the effects of hypoxia. Incapacitation can be partial, where the pilot's ability to perform some tasks is impaired, or total, where the pilot is completely unable to function.
Pilot incapacitation can have serious consequences for flight safety. The specific risks depend on the phase of flight and the severity of the incapacitation. If incapacitation occurs during a critical phase of flight, such as takeoff or landing, the risk of an accident is significantly increased. Even during the cruise phase, incapacitation can lead to a failure to respond appropriately to changing weather conditions, air traffic control instructions, or other unexpected events.
Effective crew resource management and the presence of a co-pilot can help mitigate the risks of pilot incapacitation. The co-pilot can take over the control of the aircraft if the pilot becomes incapacitated. However, this is not a fail-safe solution, particularly in the case of single-pilot operations or if the co-pilot is also affected by the same condition that caused the pilot's incapacitation.