ELT

Emergency Locator Transmitter

A small self-contained radio transmitter carried in an aircraft. If the aircraft crashes, the force of the impact automatically sets the transmitter into operation, transmitting a series of down-sweeping tones on the two emergency frequencies of 121.5 and 243.0 megahertz. Searchers who receive the signal from the ELT are able to locate the wreckage by using radio direction finding equipment.