Rans S12 N3165V accident near Mcclure, Ohio

Probable cause

The cold seizure of the cylinder/piston due to the pilot’s failure to adequately warm the engine before takeoff, which resulted in a loss of engine power during a departure climb.

NTSB analysis

The pilot warmed the engine to 120°F before taxiing to the runway for departure on a personal flight. While the airplane was climbing through 50 to 100 ft above ground level, the engine lost partial power. He ensured the throttle control was full forward and pumped the throttle control twice, but the engine speed continued to decrease. The pilot performed an off-airport landing on a field, during which the airplane stuck a power line pole and the right wing impacted the ground. After the accident, the pilot reported the engine had low cylinder compression and scoring on the piston and cylinder walls. There were also aluminum fragments within the cylinder. He said that the engine was overhauled about 1 year before his purchase of the airplane by the previous owner. He stated that he was "fairly certain" that the engine did not have any problems before the accident flight. He said the engine radiator was not covered for cold weather operation. He believed the piston failure was due to cold seizure. According to the Rotax 2-Stroke Maintenance Schedule, the engine had a minimum coolant temperature of 150°F. Given the available information, it is likely that the engine lost partial power due to a cold seizure of the cylinder/piston.

Text from the NTSB. Open the NTSB docket for CEN19LA047 for the full record.