NTSB Identification: SEA06FA054.
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Accident occurred Wednesday, February 22, 2006 in Bow, WA
Probable Cause Approval Date: 03/26/2007
Aircraft: Beech 58P, registration: N469MD
Injuries: 1 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
Approximately 11 minutes after takeoff on a night instrument flight rules flight plan, the pilot of the twin-engine airplane radioed air traffic control (ATC) that he was climbing out of 7,800 feet. Shortly thereafter, ATC received a "mayday" transmission followed by "lost an engine." Subsequently, radio communications and radar contact with the airplane were lost. Witnesses reported they observed the airplane in an unusually steep descent prior to impacting terrain. One witness stated he heard a high-pitched noise emanating from the airplane as it descended toward the ground. The wreckage was located in an open field adjacent to a highway. The main wreckage was located in the confines of a large impact crater approximately 15 feet in diameter and 6 feet deep. Dark night conditions with low ceilings prevailed at the time of the accident. Post-accident teardown and examination of both engines revealed no evidence of excessive wear or operational failure of internal engine components. Extensive damage, however, was noted to the right turbocharger assembly. Disassembly of the component revealed damage to the compressor wheel and compressor housing shroud. Circumferential scuffing and pockmarks were noted to the inner compressor housing, and impact type damage and smearing were noted to the individual compressor blades. Scuffing type damage was noted to the turbine wheel and corresponding turbine housing. Additional damage was noted to the turbine/compressor input shaft, and associated journals and bearings. Foreign material was found in the compressor housing and turbocharger after cooler. The material consisted of aluminum fragments, a rivet head, a piece of brass, paint chips, rubber, gasket material and dirt. The manufacturer of the turbo assembly examined the unit and reported the damage was consistent with FOD (foreign object damage) and lubricant starvation. The exact sequence of events leading to the failure of the turbocharger was not determined.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's failure to maintain aircraft control during the climb to cruise. Contributing factors included a loss of engine power to the right engine folowing a turbocharger failure, instrument meteorological and dark night conditions. Full narrative available
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