Definition
A built-in function on certain helicopter avionics or instruments that allows the pilot to verify the unit is operating correctly by initiating an internal check, usually by pressing a test button or selecting a test mode. The system runs a sequence that confirms internal circuitry, displays, and warning indications are working as intended.
Plain English
A button or mode on an instrument that lets the pilot check that the instrument itself is working properly before relying on it.
Context Anchor
Seen in helicopter flight manual limitations, especially before using required equipment for instrument flight.
Why Pilots Care
Confirms critical instruments are functioning before IFR flight, helping pilots meet manual limitations and maintain safety.
Intuition Check
Do not assume a self-test proves the equipment is perfect or repairs anything. It only checks the functions it was designed to check and reports whether that check passed or failed.
Example Sentence 1
Before departing IFR, the pilot ran the radar altimeter self-test feature and confirmed the warning light and audio tone activated as expected.
Example Sentence 2
Per the flight manual, the self-test feature must complete successfully prior to instrument flight.