Amateur-built P-40 N510JW accident near Oregon City, Oregon

Probable cause

The loss of total engine power due to a cold seizure.

NTSB analysis

About 30 minutes into the local flight while returning to the departure airport, the airplane's engine lost power. The pilot subsequently made a successful landing in a flat farm field. The pilot said that after adding about 2-1/2 gallons of fuel and "running it at various speeds and checking my gages," he departed for the 5 minute flight back to his original departure airport. The pilot reported that on about a 1-mile final to the runway, the engine lost power again, which required him to make a second forced landing. The airplane came to rest upright in a pond with its left wing separated. A post-accident examination revealed scuffing signature marks on the piston walls, which were consistent with a cold seizure condition. The engine manufacturer's Installation Manual specifies in its Safety Information section, in part, "This engine, by its design, is subject to sudden stoppage...Never fly the aircraft equipped with this engine at locations, airspeeds, altitude, or other circumstances from which a successful no-power landing cannot be made, after sudden engine stoppage...This is not a certificated aircraft engine."

Text from the NTSB. Open the NTSB docket for SEA08LA193 for the full record.