Plain English Meaning

The set of checks a pilot does on the ground before flying to make sure the aircraft and its instruments are working properly and safe to use.

Full Definition

A systematic inspection and verification of an aircraft and its systems performed before flight to confirm airworthiness, instrument accuracy, and proper configuration. In the context of pitot/static instruments, the preflight check includes verifying that the altimeter reads within acceptable tolerance when set to the current local altimeter setting, and that the static ports and pitot tube are unobstructed.