What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) During pre-take off hydraulic check, with hydraulics off, aircraft became airborne and rolled. Aircraft ended up on right side. (.19) on September 29, 2002, about 0854 pacific daylight time, a Eurocopter AS350-B3, N352SA, collided with terrain during a premature liftoff while engaged in a pre-departure hydraulic flight control check at the Bishop, California, airport. The u. s. forest service was operating the helicopter as a public-use flight under the provisions of 14 CFR part 91. The commercial pilot and three passengers were not injured; the helicopter sustained substantial damage. The cross-country flight was to depart the Bishop Airport for bridgeport, California. Visual meteorological conditions prevailed, and an agency flight plan had been filed. Forest service officials reported that the helicopter was engaged in a hydraulic actuator check for the first flight of the day. The collective had been placed in the down and locked position and the rotor powered up to 100 percent flight idle. After depressing the hydraulic test switch, the pilot moved the cyclic fore and aft (pumped) to confirm there was remaining pressure for a few control movements. The co llective rose uncommanded and the helicopter moved forward in a nose down attitude. The main rotor struck the ground and the helicopter made two revolutions before rolling over onto its side, destroying both the main and tail rotor systems. A small fire ensued in the exhaust area, but was quickly extinguished. A postcrash examination was conducted, which revealed a deteriorated condition in the collective's locking mechanism. The stud was worn and the collective would come loose during movement of the cyclic. The forest service investigators also found this condition on another of their helicopters of the same type.
As the FAA filed it
(-23) DURING PRE-TAKE OFF HYDRAULIC CHECK, WITH HYDRAULICS OFF, AIRCRAFT BECAME AIRBORNE AND ROLLED. AIRCRAFT ENDED UP ON RIGHT SIDE. (.19) ON SEPTEMBER 29, 2002, ABOUT 0854 PACIFIC DAYLIGHT TIME, A EUROCOPTER AS350-B3, N352SA, COLLIDED WITH TERRAIN DURING A PREMATURE LIFTOFF WHILE ENGAGED IN A PRE-DEPARTURE HYDRAULIC FLIGHT CONTROL CHECK AT THE BISHOP, CALIFORNIA, AIRPORT. THE U. S. FOREST SERVICE WAS OPERATING THE HELICOPTER AS A PUBLIC-USE FLIGHT UNDER THE PROVISIONS OF 14 CFR PART 91. THE COMMERCIAL PILOT AND THREE PASSENGERS WERE NOT INJURED; THE HELICOPTER SUSTAINED SUBSTANTIAL DAMAGE. THE CROSS-COUNTRY FLIGHT WAS TO DEPART THE BISHOP AIRPORT FOR BRIDGEPORT, CALIFORNIA. VISUAL METEOROLOGICAL CONDITIONS PREVAILED, AND AN AGENCY FLIGHT PLAN HAD BEEN FILED. FOREST SERVICE OFFICIALS REPORTED THAT THE HELICOPTER WAS ENGAGED IN A HYDRAULIC ACTUATOR CHECK FOR THE FIRST FLIGHT OF THE DAY. THE COLLECTIVE HAD BEEN PLACED IN THE DOWN AND LOCKED POSITION AND THE ROTOR POWERED UP TO 100 PERCENT FLIGHT IDLE. AFTER DEPRESSING THE HYDRAULIC TEST SWITCH, THE PILOT MOVED THE CYCLIC FORE AND AFT (PUMPED) TO CONFIRM THERE WAS REMAINING PRESSURE FOR A FEW CONTROL MOVEMENTS. THE CO LLECTIVE ROSE UNCOMMANDED AND THE HELICOPTER MOVED FORWARD IN A NOSE DOWN ATTITUDE. THE MAIN ROTOR STRUCK THE GROUND AND THE HELICOPTER MADE TWO REVOLUTIONS BEFORE ROLLING OVER ONTO ITS SIDE, DESTROYING BOTH THE MAIN AND TAIL ROTOR SYSTEMS. A SMALL FIRE ENSUED IN THE EXHAUST AREA, BUT WAS QUICKLY EXTINGUISHED. A POSTCRASH EXAMINATION WAS CONDUCTED, WHICH REVEALED A DETERIORATED CONDITION IN THE COLLECTIVE'S LOCKING MECHANISM. THE STUD WAS WORN AND THE COLLECTIVE WOULD COME LOOSE DURING MOVEMENT OF THE CYCLIC. THE FOREST SERVICE INVESTIGATORS ALSO FOUND THIS CONDITION ON ANOTHER OF THEIR HELICOPTERS OF THE SAME TYPE.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.