NTSB Identification: SEA82DA044
14 CFR Part 91: General Aviation
Accident occurred Friday, April 02, 1982 in NEAR TOUTLE, WA
Probable Cause Approval Date: 04/02/1983
Aircraft: HILLER UH-12E, registration: N9060F
Injuries: 4 Uninjured.

ABOUT 1 1/2 MINUTES AFTER TAKEOFF, THE PILOT HEARD A LOUD "BANG" WHICH WAS FOLLOWED BY A VERTICAL AND LATERAL VIBRATION. THE HELICOPTER BEGAN TO DESCEND, PITCH FORWARD, AND ROLL RIGHT AS THE VIBRATION INCREASED. THE PILOT ELECTED TO MAKE AN AUTOROTATIVE LANDING ON A NEARBY SAND BAR. AS THE HELICOPTER TOUCHED DOWN ON SLOPING TERRAIN, IT ROLLED OVER ON ITS RIGHT SIDE AND WAS SUBSTANTIALLY DAMAGED. DURING THE INVESTIGATION, THE TRANSMISSION AND THE ENGINE WERE DISASSEMBLED, BUT NO DISCREPANCIES WERE FOUND. ONE OF THE MAIN ROTOR BLADE CAPS HAD SEPARATED. HOWEVER, THE INVESTIGATOR WAS UNABLE TO DETERMINE WHETHER THE BLADE CAP SEPARATED BEFORE OR AFTER IMPACT. THE CAP WAS NOT FOUND.

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

REASON FOR OCCURRENCE UNDETERMINED


Contributing Factors

FUSELAGE..VIBRATION


Contributing Factors

AUTOROTATION..PERFORMED..PILOT IN COMMAND


Contributing Factors

TERRAIN CONDITION..SAND BAR


Contributing Factors

TERRAIN CONDITION..ROUGH/UNEVEN

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