NTSB Identification: NYC88FA166.
The docket is stored on NTSB microfiche number 38660.
Accident occurred Friday, June 17, 1988 in SPRINGTOWN, PA
Probable Cause Approval Date: 01/24/1990
Aircraft: Bell 206L-1, registration: N114FH
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.

WHILE IN CRUISE FLIGHT, GROUND WITNESSES OBSERVED THE HELICOPTER MAKE TWO VIOLENT ROLL MANEUVERS FOLLOWED BY AN IN-FLIGHT BREAKUP. AIRCRAFT WRECKAGE WAS SPREAD OVER AN AREA OF APPROXIMATELY 10 ACRES. EXAMINATION OF THE WRECKAGE REVEALED THAT THE COLLECTIVE IDLER LINK AND RETAINING PIN ASSEMBLY WERE MISSING AND THE LOWER ATTACHING STUD OF THE IDLER LINK SHOWED EVIDENCE OF FAILURE. THE STUD WAS BENT IN THE DIRECTION OPPOSITE TO THE DIRECTION OF ROTATION AND SHEARED NUT THREADS AND COTTER PIN REMAINS WERE FOUND IN THE STUD THREADS AND COTTER PIN HOLE, RESPECTIVELY. THE H-SHAPED IDLER LEVER THAT CONNECTS THE UPPER END OF THE IDLER LINK TO THE SWASHPLATE DRIVE COLLAR WAS FOUND ATTACHED TO THE COLLAR AND SHOWED NO EVIDENCE OF DISTRESS. IT COULD NOT BE DETERMINED WHY THE RETAINING PIN CONNECTING THE COLLECTIVE IDLER LINK TO THE IDLER LEVER SEPARATED.

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

ROTORCRAFT FLIGHT CONTROL,SWASHPLATE ASSEMBLY..DISENGAGED


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