flag alarm

flag alarm

[′flag ə‚lärm] (engineering) A semaphore-type flag in the indicator of an instrument to serve as a signal, usually to warn that the indications are unreliable.

flag

A small brightly colored plate inside a certain airborne navigation, or a flight instrument, that comes into view to indicate the malfunction of a system or the instrument itself. It also can indicate that the signal strength or quality of the received signal has fallen below the acceptable values. Also called a flag alarm.