The crash of a de Havilland DHC 3-T single-turbine floatplane in Alaska in which 4 badly injured survivors' lives were put at risk by the failure of the aircraft's emergency locator transmitter has worried the NTSB. The NTSB has voiced its concern that the widely used system is vulnerable to a similar failure in future. On August 9, 2010, the Otter was carrying 9 people, 8 passengers and a Pilot, between remote fishing lodges in Alaska. It hit high ground in marginal visual meteorological conditions, killing the Pilot and 4 passengers, and badly injuring the surviving 4. Among those killed was former Alaska Senator Ted Stevens. Almost 4 hours, after its departure, a telephone inquiry by a manager at the departure point asking about the aircraft's anticipated return, established that the aircraft had not arrived at its destination. The NTSB found that it had crashed about 15 minutes after takeoff in high wooded ground 18.6 miles N of Dillingham in southern Alaska. A search by volunteer aviators along the planned route, with no help from the aircraft's transmitter, established the position of the wreckage, but the weather closed in and paramedics could not access the site until the following day to recover the survivors. The NTSB found that the Artex ME406 ELT, designed to broadcast signals via an externally mounted antenna, had become separated from its mounting tray and thus from the external antenna, so although the system was triggered by the crash, the signals were not transmitted. The ELT is designed to send a 406MHz signal relaying the aircraft's position by satellite to emergency personnel, but it also transmits a homing signal on the VHF emergency frequency 121.5 MHz for search aircraft to use. The NTSB has called for the FAA to require an immediate check of all general aviation ELTs to ensure that they are mounted according to specification, and in the longer term to determine whether the mounting requirements are sufficiently robust in the light of this crash.
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