Plain English Meaning

Things going on inside the pilot's body or head that can make them fly worse, even if the aircraft is working perfectly.

Full Definition

Conditions affecting the pilot's body and mind that can degrade performance in flight, including hypoxia, hyperventilation, dehydration, fatigue, stress, motion sickness, spatial disorientation, and the effects of alcohol, drugs, or carbon monoxide.

Context Anchor

Seen in safety and preflight self-check discussions, especially when deciding whether you are fit to fly.