NTSB Identification: NYC06LA106.
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Accident occurred Thursday, May 04, 2006 in Kings Park, NY
Probable Cause Approval Date: 02/26/2007
Aircraft: Schweizer 269C, registration: N38DM
Injuries: 2 Minor.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The helicopter was in cruise flight, about 1,400 feet above ground level, when the flight instructor heard a "rumbling" from beneath and behind the cockpit. Soon after, the rumbling became louder, the oil temperature increased, the oil pressure dropped to "zero," and the engine stopped producing power. The flight instructor adjusted the flight controls for autorotation, and selected a high school athletic field for the forced landing. He attempted to extend the helicopter's glide to reach the field, while maintaining rotor rpm. Just prior to touchdown, the tail of the helicopter struck the athletic field's perimeter fence, which resulted in a loss of control, and collision with terrain. Examination of the helicopter's engine revealed that the oil suction screen was completely occluded by metal particles. The number 3 cylinder was removed, and the associated piston and connecting rod were stuck in the cylinder bore. The connecting rod was fractured at the yoke, and free of the crankshaft. The connecting rod cap was fragmented, and the fragments were found scattered in the oil sump. The number 3 connecting rod bearing material was completely extruded and fragmented, and a mode of failure could not be determined. Examination of the engine maintenance records revealed that the engine had accrued 2,157 total hours of operation, 759 total hours since overhaul, and 90 total hours since the number 1 cylinder assembly was replaced due to low compression and a broken piston ring.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: Loss of engine power due to the failure of the number 3 connecting rod bearing. A contributing factor was the lack of suitable terrain for the emrgency landing. Full narrative available
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