Based on recent history, the NTSB Friday sent two safety recommendations to the FAA requiring operators to inspect the mountings of all ELT transmitters installed on general aviation aircraft to ensure the units don’t break free in a crash. The recommendations (PDF) are the byproduct of the de Havilland turbine Otter crash in Alaska on Aug. 9, 2010, that killed five, including former U.S. Senator Ted Stevens. The wreckage was found nearly five hours after the crash and while its 406 Mhz ELT had activated, the unit had separated from its antenna. No satellites, or rescue aircraft involved in the search, were able to detect the signal, according to the NTSB. NTSB Chairman Deborah Hersman summed up the problem simply. “This vital life-saving technology won’t do anyone any good if it doesn’t stay connected to the antenna,” said Hersman.
The specific emergency locator transmitter involved in the Otter crash was an Artex ME406, which “consisted of a mounting tray affixed to the aircraft and an ELT module that ‘nested’ in the tray.” A first responder found the unit loose on the aft floor of the plane. It was switched on, but “showed evidence that the antenna and remote switch cable had been pulled out.” The NTSB did not determine if that separation was the result of improper mounting or other factors. The NTSB is concerned that other units similar to the ME406 are at risk of being thrown free of their mounting trays with similar results. Generally, the NTSB recommends that during annual inspections, all emergency locator transmitters undergo detailed inspections to ensure they are mounted per the manufacturer’s specifications. It further recommends that the FAA determine if current mounting requirements and retention tests are adequate.