NTSB Identification: LAX85FA286.
The docket is stored on NTSB microfiche number 29649.
Accident occurred Wednesday, June 19, 1985 in SQUAW VALLEY, CA
Aircraft: BELL 214B-1, registration: N214RM
Injuries: 2 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.
THE HELICOPTER WAS ENGAGED IN LOWERING A LARGE POLE TO THE GROUND WHEN THE ENG FAILED CATASTROPHICALLY DUE TO A TOTAL FIRST TURBINE ROTOR DISC FAILURE. THE PLT TURNED THE ACFT DOWN THE MOUNTAIN BUT WAS UNABLE TO GAIN ENOUGH SPEED TO AUTOROTATE. THE ACFT IMPACTED AT AN ANGLE AND BURNED. NO PARTS OF THE FIRST TURBINE ROTOR DISC WERE RECOVERED, THEREFORE, A FAILURE MODE COULD NOT BE DETERMINED. THE DISC HAD ACCUMULATED 2776 CYCLES AT THE TIME OF THE ACCIDENT. LYCOMING SERVICE BULLETIN NO. 5508-0002 REPORTS THE SERVICE LIFE LIMIT FOR THE DISC IS 2700 CYCLES. AN ENG TEARDOWN REVEALED NOTHING ELSE WRONG WITH THE ENG THAT COULD HAVE CONTRIBUTED TO ITS FAILURE OTHER THAN THE FIRST TURBINE ROTOR DISC DISINTEGRATION.
The National Transportation Safety Board determines the probable cause(s) of this accident to be:MAINTENANCE,REPLACEMENT..NOT IDENTIFIED..MANUFACTURER
The National Transportation Safety Board determines the probable cause(s) of this accident to be:MATERIAL INADEQUATE..MANUFACTURER
The National Transportation Safety Board determines the probable cause(s) of this accident to be:MATERIAL DEFECT..MANUFACTURER
TURBINE ASSEMBLY,TURBINE WHEEL..DISINTEGRATED
TURBOSHAFT ENGINE,GAS GENERATOR TURBINE..FAILURE,TOTAL
AUTOROTATION..ATTEMPTED..PILOT IN COMMAND
ALTITUDE..INADEQUATE..PILOT IN COMMAND
FLARE..NOT POSSIBLE..PILOT IN COMMAND
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