Definition
A personal preflight self-assessment used by pilots to evaluate their fitness to fly. The pilot checks themselves against six factors -- Illness, Medication, Stress, Alcohol, Fatigue, and Emotion -- and only flies if none of them are impairing their ability to operate the aircraft safely.
Plain English
A short mental check a pilot runs on themselves before flying, to make sure they are healthy, clear-headed, and rested enough to fly safely. If any of the six items is a problem, the pilot doesn't go.
Context Anchor
Used during preflight planning and in the “Pilot” part of the PAVE checklist to judge the pilot’s own readiness before a flight.
Derivation
IMSAFE is a memory aid built from the first letters of the six items it covers. It is designed to be easy to recall in the cockpit or at the planning desk, where a longer checklist might be skipped.
Why Pilots Care
Helps prevent accidents caused by pilot impairment that could affect judgment or aircraft control.
Grounding Statement
The IMSAFE checklist is a quick pause before flight to check whether the pilot is personally fit to act as pilot in command.
Intuition Check
Do not treat “IMSAFE” as a guarantee that everything is safe. It is a reminder to honestly check your own condition before deciding to fly.
Example Sentence 1
Before her early morning flight, she ran through the IMSAFE checklist and decided to delay departure because she had only slept four hours.
Example Sentence 2
Even on short flights, instructors remind students to run the IMSAFE checklist first.