Definition
The recognizable physical, mental, and emotional indicators that a pilot is becoming fatigued and that performance, judgment, and situational awareness are degrading. Common indicators include slowed reaction time, difficulty concentrating, lapses in attention, forgetfulness, irritability, poor decision-making, fixation, heavy eyelids, frequent yawning, and a tendency to overlook or miss routine items. Recognizing these signs is the trigger for taking corrective action before fatigue compromises safety of flight.
Plain English
These are the clues your body and mind give you when you're getting tired. Things like trouble focusing, slower reactions, missing checklist items, getting cranky, or struggling to keep your eyes open. They're a signal to stop, rest, or hand off the flying before tiredness causes a mistake.
Context Anchor
Used in human factors and flight instruction discussions, especially when teaching students to recognize when tiredness is reducing awareness and performance.
Derivation
Fatigue comes from a Latin word meaning to tire out. That helps here because aviation fatigue is not just feeling sleepy; it is a worn-down state where the body and mind no longer perform as well.
Why Pilots Care
Recognizing these signs early allows intervention before fatigue leads to errors or loss of control.
Grounding Statement
A pilot may still be awake and talking normally while fatigue is already reducing attention and decision-making.
Intuition Check
Do not assume fatigue only means falling asleep. In aviation, fatigue can show up earlier as slower thinking, small mistakes, irritability, fixation on one task, or reduced awareness.
Example Sentence 1
Halfway through the cross-country, the pilot recognized warning signs of fatigue -- two missed radio calls and difficulty holding altitude -- and elected to land for a break.
Example Sentence 2
Monitoring for warning signs of fatigue is essential during night operations.