What is the primary frequency that the ELT uses for civilian aircraft distress?

The Emergency Locator Transmitter (ELT) primarily uses the frequency of 121.5 MHz for civilian aircraft distress situations. This frequency was widely recognized and utilized for distress signaling, allowing search and rescue operations to locate aircraft in emergencies. When activated, the ELT broadcasts a continuous signal on this frequency, which can be picked up by search and rescue aircraft and ground stations equipped to monitor 121.5 MHz.

Although 406 MHz is also associated with newer ELT models and provides advantages such as satellite-based positioning and faster response times, the long-standing use of 121.5 MHz for emergency distress calls makes it the primary frequency historically assigned to civilian aircraft. Thus, in the context of traditional emergency responses, 121.5 MHz is viewed as the main distress frequency for civilian aviation.