On which frequency does an emergency locator transmitter (ELT) transmit?

The emergency locator transmitter (ELT) is designed to transmit distress signals when an aircraft is involved in an accident or emergency situation. The primary frequencies on which ELTs operate include 121.5 MHz for the search and rescue purpose; however, the more modern and globally recognized frequency for ELTs is 406 MHz.

The 406 MHz signal is used for satellite tracking and offers enhanced features such as automatic identification and the ability to transmit location information via GPS. This frequency is important because it ensures a more timely and precise response from search and rescue teams, as it can be detected via dedicated satellites and provides critical information that can expedite finding the downed aircraft and its occupants.

While the frequency of 121.5 MHz was used for many years and still remains as a backup frequency for ELTs, it is being phased out in terms of its efficiency and capability in a satellite environment. Therefore, it is the 406 MHz frequency that is the correct answer for the main transmission of modern ELTs.