What does the Emergency Locator Transmitter transmit on?

The Emergency Locator Transmitter (ELT) is designed to assist in search and rescue operations by transmitting distress signals. The key frequencies associated with ELTs are critical for their function. Specifically, the ELT transmits on the international distress frequency of 121.5 MHz, which is a conventional frequency used for emergency signaling in aviation.

This frequency enables search and rescue aircraft to detect signals from downed aircraft, as air traffic control and rescue services monitor 121.5 MHz. The use of this frequency allows for wide coverage and the ability to quickly locate those in need of assistance.

While there are other frequencies connected to different types of emergency beacons, the specific focus on 121.5 MHz highlights its significant role in traditional emergency efforts. The option regarding the frequency of 406 MHz is related to more modern, satellite-compatible ELTs that improve accuracy and detection, but it is not the primary signal used for immediate distress.

The correct choice emphasizes the essential protocol of aviation emergency distress signaling and reflects the operational standards recognized internationally for conducting search and rescue functions.