ALIKA Aviation Eurocopter AS350D accident

During cruise flight the helicopter lost all engine power. The pilot made a hard forced during the autorotative descent onto a road. Post accident disassembly and examination of the engine disclosed that the power loss was due to the number two bearing sustaining significant damage [heavy roller deformation] and heat distress, consistent with an operating event with an insufficient oil supply. The engine had been leased by the operator from another firm. The operator's Director of Maintenance had installed the engine 13 operational hours prior to the accident flight. The record examination revealed, in part, that: (1) The engine’s serial number (S/N) data plate was defaced such that the S/N’s fifth numeric digit appears to have been overstruck onto the data plate, rendering the original, underlying digit illegible; (2) A 2003 logbook entry indicated that the engine was sold in an “as is” condition and was unserviceable, but the entry had a single line drawn through it with the word “void” and signed initials appearing above it; (3) a 2004 logbook entry indicated that long-term preservation was not accomplished, further maintenance was required, and a determination of serviceability was required before the next flight; and (4) the engine received an FAA Form 8130-3, “Airworthiness Approval Tag,” dated December 18, 2005, which certified that the engine was in “a condition for safe operation” and was found to be suitable for “return to service” per 14 CFR 43.9. The pilot stated that he did not observe illumination of any annunciator warning light on the helicopter's cockpit warning annunciator panel (CWP) prior to the power loss event. Illumination of CWP lights provides the pilot with an early indication of an impending problem. The brightness control switch on the CWP was found in the minimum brightness position, rather than in the maximum position recommended for daylight operation.

Verbatim NTSB analysis and probable cause from the NTSB dataset