NTSB Identification: WPR11LA183
14 CFR Part 91: General Aviation
Accident occurred Sunday, April 03, 2011 in Pleasant Grove, CA
Probable Cause Approval Date: 08/07/2012
Aircraft: TOMEI S12 XL, registration: N8113N
Injuries: 1 Fatal.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

A pilot-rated witness said that the airplane was airborne within “a couple of minutes” after the engine was started and that, when the airplane reached an altitude of 200 to 300 feet above the ground during climb out, it appeared to slow. The witness said that the airplane then banked left and descended in a spiral until it impacted the ground. Postaccident examination of the engine revealed evidence of abnormal piston wear and cylinder damage, including mechanical scoring and vertical grooves along the forward cylinder walls and piston skirt. A representative of the engine manufacturer reported that the observed cylinder and piston damage was consistent with an in-flight cold seizure of the piston (a condition where the piston seizes within the cylinder). About 17 years before the accident, the engine manufacturer issued a Service Information Letter (SIL) that addressed the potential for such a piston seizure. The SIL stated in part “...Putting a cold engine to hard work without uniform and correct warm up will cause the piston to expand quicker than the cylinder, minimizing clearance and creating piston scuffing and seizure.” It is likely that the pilot did not allow enough time for the engine to warm up before taking off.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot’s failure to allow the airplane’s engine to properly warm up before applying takeoff power, which resulted in the forward cylinder's piston seizing and a subsequent loss of engine power. Also causal was the pilot's failure to maintain an adequate airspeed after the loss of engine power, which resulted in a stall-spin.

Full narrative available

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