NTSB Identification: SEA90LA025.
The docket is stored on NTSB microfiche number 41257.
Accident occurred Wednesday, November 29, 1989 in RAYMOND, WA
Probable Cause Approval Date: 06/26/1992
Aircraft: HILLER UH-12E, registration: N9762C
Injuries: 1 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
DURING AN EXTERNAL LOAD OPERATION, WHILE HAULING A LOAD UPHILL TO THE LANDING ZONE, THE PILOT HEARD A LOUD NOISE AND THE ENGINE BEGAN TO LOSE POWER. THE PILOT RELEASED THE LOAD AND AUTOROTATED TO A LANDING ON INCLINED TERRAIN. WHILE LANDING, THE HELICOPTER ROLLED OVER. DURING AN ENGINE TEARDOWN, A SECTION OF THE IMPELLER WAS FOUND TO HAVE FAILED FROM FATIGUE, WHICH RESULTED IN ADDITIONAL DAMAGE TO THE ENGINE AND A LOSS OF POWER.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: LOSS OF ENGINE POWER DUE TO FATIGUE FAILURE OF THE IMPELLER. THE HELICOPTER WAS SUBSTANTIALLY DAMAGED AS A RESULT OF A ROLL-OVER ON UNEVEN TERRAIN.
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