ERA09LA455

The pilot of a powered glider experienced a partial loss of engine power on takeoff and landed hard while attempting a go around. During the preflight inspection and engine run-up, the pilot saw nothing abnormal that would have suggested a problem with the engine. After the accident, the pilot removed the powered glider wreckage from the accident site before the FAA inspector could inspect it. Approximately 3 months later, the powered glider was examined by an independent airframe and powerplant mechanic, and no definitive evidence was found that would have caused the partial loss of engine power. The inspection did reveal damage to the cylinder walls, but it was not possible to correlate this with the partial loss of engine power due to the engine being previously disassembled and examined by the owner.

On August 8, 2009, about 0945 central daylight time, a Schempp-Hirth Ventus 2cM powered glider, N70ZZ, registered to a private individual, impacted terrain while returning to land following a reported partial loss of engine power during the initial takeoff climb from St Elmo Airport (2R5), St Elmo, Alabama. Visual meteorological conditions prevailed at the time of the accident and no flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 91 personal, local flight. The powered glider was substantially damaged and the private pilot, the sole occupant sustained minor injuries. The flight was originating at the time of the accident. The pilot stated that before takeoff the fuselage fuel tank was full with 100 low lead (100LL) fuel, but he was unable to check the tank for contaminants during his preflight inspection due to the location of the sump drain. He performed an engine run-up and noted a 100 and 200 rpm drop when checking each ignition system, though he did not recall what system had what specific drop. He began the takeoff roll from runway 06 with the wind from the east-southeast at 5 to 6 knots, and based on his 400 hours in powered gliders, the takeoff roll was longer than normal. He continued the takeoff and when the flight was between 150 and 200 feet, he noted that the engine rpm had dropped to approximately 70 to 80 percent of full power. At that point the powered glider was climbing slowly and he thought about landing straight ahead in a field or a return for landing; he elected to return thinking the engine was producing enough power. As, he turned downwind, the powered glider felt mushy and he realized that he would not make it back to the runway. He applied forward elevator input and the powered glider impacted the ground in a slight right wing low attitude resulting in substantial damage to the fuselage, right wing, and the horizontal and vertical tail assemblies. He exited the powered glider and removed the wreckage from the accident site before a Federal Aviation Administration (FAA) inspector could inspect it. Inspection of the powered glider with oversight by the FAA was not able to be coordinated, and approximately 3 months after the accident an independent airframe and power plant (A&P) mechanic was hired to examine the powered glider. The A&P stated that when the powered glider was delivered to him, he was told and it was evident that the owner had partially disassembled the engine in an effort to examine it. The inspection revealed that the ignition system worked properly, and there was no definitive evidence of any pre-impact anomalies that would have caused the partial loss of engine power. The inspection did reveal damage to the cylinder walls, but it was not possible to correlate this with the partial loss of engine power due to the engine being previously disassembled.