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Aviation Accident


NTSB Identification: NYC86FHD01
The docket is stored on NTSB microfiche number 32618.
Accident occurred Tuesday, July 01, 1986 in LAKEHURST, NJ
Aircraft: Piasecki Acft. Corp. HELISTAT 97-34J, registration: N1897Z
Injuries: 1 Fatal, 3 Serious, 1 Minor.

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 HELISTAT, A HYBRID A/C WITH 4 H-34 MAIN FUSELAGES ATTACHED TO A FRAME ALONG WITH A ZPG-2 HELIUM FILLED ENVELOPE HAD JUST COMPLETED IT FIRST HOVER TEST FLT SUCCESSFULLY AND LANDED. A PWR LOSS WAS NOTED ON THE NO. 3 HELICOPTER AND THE TEST WAS TERMINATED AND THE MOORING MAST CALLED FOR. PRIOR TO RE-MOORING A WIND SHIFT CAUSED AN UNCOMMANDED LEFT TURN WHICH THE PILOT COULD NOT CONTROL WITH THE FLT CONTROLS. WITH A TAILWIND, NO WHEEL BRAKES OR GND STEERING A TAKEOFF WAS ATTEMPTED. THE 4 MAIN LANDING GEAR WHICH HAD NO SHIMMY DAMPNERS STARTED TO SHIMMY. THE FOUR HELICOPTERS STARTED TO REACT TO THE SHIMMY WITH GROUND RESONANCE. AS THE HELISTAT FINALLY LIFTED OFF, THE FOUR INDIVIDUAL HELICOPTERS BROKE OFF AND FELL TO THE GROUND. ONE PILOT RECEIVED FATAL INJURIES, 3 RECEIVED SERIOUS INJURIES AND ONE MINOR INJURIES. THE HELISTAT WAS DESTROYED. THE PRW LOSS ON THE NO. 3 HELICOPTER WAS TRACED TO A MISSING THROTTLE LINKAGE CORRELATION PIN. WHY THE PIN WAS MISSING WAS NOT DETERMINED.


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

  • THROTTLE/POWER LEVER,LINKAGE..DISCONNECTED
  • ROTORCRAFT FLIGHT CONTROL..INADEQUATE
  • ACFT/EQUIP,INADEQUATE DESIGN..MANUFACTURER
  • ACFT/EQUIP,INADEQUATE HANDLING/PERF CAPABILITIES..MANUFACTURER

Contributing Factors:
  • LANDING GEAR,MAIN GEAR..VIBRATION
  • LANDING GEAR,NORMAL BRAKE SYSTEM..LACK OF
  • ROTOR SYSTEM..VIBRATION
  • LANDING GEAR,STEERING SYSTEM..LACK OF
Full narrative is not available