What frequency does an ELT emit on when activated, according to standard maintenance procedures?

• A. 121.5 MHz
• B. 406 MHz
• C. 243 MHz
• D. 1090 MHz

Answer: (B)

Modern ELTs transmit the distress signal on 406 MHz when activated. This frequency is the satellite-detected channel used by the COSPAS-SARSAT system to alert authorities and provide beacon information for locating the aircraft. The older 121.5 MHz frequency is mainly a local homing aid for ground search teams, not the primary distress signal relied on in standard maintenance procedures. The other frequencies listed are not the standard civilian ELT distress channel used for SAR activation. So, the frequency emitted during standard maintenance activation is 406 MHz.