EMERGENCY LOCATOR TRANSMITTERS
Emergency Locator Transmitter. A radio transmitter attached to the aircraft structure which operates from its own power source on 121.5 MHz and 243 MHz. The transmitter transmits a distinctive downward swept audio tone for homing purposes and is designed to function without human action after an accident.
Emergency Locator Transmitter - A low-power transmitting device carried on light aircraft as required by federal law, and on most military aircraft. It is impact activated and transmits a distinctive sweeping tone that can be detected by aircraft mounted or hand-held direction finding (DF) equipment.