NTSB Identification: LAX90FA268.
The docket is stored on NTSB microfiche number 44579.
Nonscheduled 14 CFR
Accident occurred Wednesday, July 25, 1990 in QUINCY, CA
Probable Cause Approval Date: 12/30/1992
Aircraft: BELL 206B, registration: N2292W
Injuries: 4 Uninjured.

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.

THE PILOT WAS CONDUCTING A HELICOPTER AERIAL SURVEY AND WAS CRUISING AT 400 FT AGL IN MOUNTAINOUS TERRAIN WHEN THE ENGINE, WITHOUT ANY WARNING, SUSTAINED A FLAME OUT. THE PILOT IMMEDIATELY EXECUTED AN AUTOROTATION AND WAS ABLE TO FIND A SUITABLE LANDING AREA. ON FINAL APPROACH HE OBSERVED A STEEL CABLE TRAVERSING THE LANDING SITE DIRECTLY IN THE HELICOPTER'S FLIGHT PATH. HE WAS ABLE TO FLY OVER THE CABLE BUT IN DOING SO THE MAIN ROTOR RPM DECAYED AND THE HELICOPTER SUSTAINED A HARD LANDING. THE POST ACCIDENT INVESTIGATION DISCLOSED THAT THE ENGINE WOULD NOT OPERATE AT GOVERNOR POWER LEVEL ANGLES OF LESS THAN 50 DEG. AFTER BENCH TESTING THE POWER TURBINE GOVERNOR IT OPERATED NORMALLY WHEN PLACED ON THE ENGINE. TEST ENGINEERS REPORTED THAT THIS CONDITIONS, IN ALL PROBABILITY, INDICATES A CONTAMINATE LODGED IN THE POWER TURBINE GOVERNOR. IT WAS DISCLODGED DURING THE BENCH TEST.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

AN UNIDENTIFIED CONTAMINATE LODGED IN THE FUEL GOVERNOR.

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