At the request of the FAA, the Federal Communications Commission (FCC) on January 11 rescinded its rule prohibiting the “certification, manufacture, importation, sale or use of emergency locator transmitters (ELTs) that transmit distress alerts on frequency 121.5 MHz.” Monitoring of 121.5-MHZ ELT signals by the international Cospas-Sarsat satellite system ended on Feb. 1, 2009, and aircraft owners and operators are advised to switch to ELTs that broadcast on 406 MHz.
The FAA notified the FCC last July that it was concerned that the supply of 406-MHz ELTs was insufficient and also that 121.5-MHz ELTs are still monitored by the search-and-rescue community. FAA regulations require most aircraft to carry an ELT, and the FCC regulation would have made installing a 406-MHz unit mandatory, thus grounding any aircraft until the new ELT could be installed.
In its investigation of the Aug. 9, 2010, crash of a de Havilland Canada turboprop Otter near Aleknagik, Alaska, the NTSB found that the 406-MHz ELT installed in the airplane broke loose and detached from the antenna. The satellite network and search teams were not able to detect the ELT’s signals, even though the ELT operated normally. The NTSB noted, “It is possible that the ELT was not installed correctly, either at the time of installation or after the periodic inspections. The NTSB concludes that proper installation and inspection of ELT units is imperative to ensure they remain connected to the antenna and maintain functionality for rapid notification of aircraft accidents and prompt emergency response.”