Pilot Debrief

TOMEI S12 XL near Pleasant Grove, CA — 2011-04-03

Final reportWPR11LA183
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Date
2011-04-03
Location
Pleasant Grove, CA, USA
Airport
PVT
Aircraft
TOMEI S12 XL
Registration
N8113N
Category
Airplane
Highest injury
Fatal
Fatalities
1
Phase of flight
Takeoff roll

Probable cause

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.

NTSB narrative

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.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Proper engine warm-up before takeoff could have prevented the seizure.

NTSB coding

Evidence available

  • Photos
  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

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