Plain English Meaning
A small radio beacon fitted to the aircraft that switches itself on if the airplane crashes, sending out a signal so rescuers can find it.
Full Definition
A self-contained, battery-powered radio transmitter installed in an aircraft that automatically activates on impact and broadcasts a distress signal on designated emergency frequencies (121.5 MHz, 243.0 MHz, and/or 406 MHz) to help search and rescue services locate the aircraft after a crash or forced landing.
Context Anchor
Pilots encounter this term when checking required emergency equipment, reviewing aircraft records, or learning what happens after an accident or forced landing.