Kings Park, NY, USA
N38DM
Schweizer 269C
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.
On May 4, 2006, at 1030 eastern daylight time, a Schweizer 269C, N38DM, operated by Wings Air, LLC, was substantially damaged in Kings Park, New York, after it contacted a fence and impacted terrain during a forced landing. The certificated flight instructor and non-certificated student pilot received minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the flight that departed Long Island MacArthur Airport (ISP), Ronkonkoma, New York, about 1020. The instructional flight was conducted under 14 CFR Part 91. In a telephone interview, the instructor said that the helicopter was in cruise flight, about 1,400 feet above ground level, when he heard a "rumbling" from beneath and behind the cockpit. He said that from past experience, the sound was occasionally indicative of a "stuck valve", and that he was not immediately alarmed. Soon after, the rumbling "got loud," the oil temperature "got high," the oil pressure "dropped to zero," and the engine "just quit." 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. The instructor reported that there were no deficiencies with performance and handling of the helicopter prior to the loss of engine power. The student pilot's account of events was consistent with the instructor's. He said that he was monitoring the engine gauges when the rumbling sound began, and watched the oil pressure gauge "drop to zero" before the power loss. The flight instructor held a commercial pilot certificate with ratings for airplane single-engine land, multi-engine land, rotorcraft helicopter, and instrument airplane and helicopter. He reported 1,600 total hours of flight experience, 1,100 hours of which were in helicopters, and 900 hours of which were in make and model. His most recent second-class medical certificate was issued in January 2006. The student pilot held no certificates, and had accrued 2 hours of flight instruction. The helicopter had accrued 2,157 total hours of operation. It's most recent 25-hour inspection was completed on April 12, 2006. The helicopter was examined and photographed at the site by a Federal Aviation Administration (FAA) Inspector. Examination revealed that all major components of the helicopter were accounted for at the scene. After a cursory examination of the wreckage, the helicopter was moved to a secure facility on the MacArthur/Islip Airport. Examination of the engine revealed that the engine could not be rotated by hand. Removal of the oil suction screen revealed a high concentration of metal particles. The engine examination was suspended, and the engine was moved to the Lycoming Engines Factory, Williamsport, Pennsylvania, for further examination. On August 29, 2006, engine was examined at Lycoming Engines, Williamsport, Pennsylvania. It was placed on an examination stand and the oil suction screen was removed. Examination revealed that the 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. The engine was manufactured in 1990, and had accrued 2,157 total hours of operation. The most recent overhaul was conducted in January 2003. The engine accrued 759 total hours since overhaul. On January 16, 2006, at 669 hours since overhaul, the number 1 cylinder assembly was replaced due to low compression. According to the logbook entry, "Found broken ring, bore worn out, installed [overhauled cylinder assembly]." At 1056, the weather reported at Long Island MacArthur Airport, included few clouds at 3,500 feet and winds from 300 degrees at 5 knots. The temperature was 66 degrees Fahrenheit, and the dew point was 53 degrees Fahrenheit.
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.
Source: NTSB Aviation Accident Database
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