Amateur-built PITTS MODEL 12 N488WT accident near Lagrange, Georgia

Probable cause

A partial loss of engine power after takeoff for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation.

NTSB analysis

According to the private pilot, shortly after takeoff for a cross-country flight in the experimental, amateur-built airplane, the engine rpm "quickly dropped to idle." He verified that the electric fuel boost pump was on and switched to the auxiliary fuel tank, but the engine performance did not improve. The airplane was unable to reach the airport, so the pilot performed a forced landing in a field. During the landing, the airplane nosed down and then came to a stop, which resulted in structural damage to the airplane and serious injuries to the pilot.

An examination of the fuel system revealed no evidence of fuel interruption, blockage, or contamination. Internal engine continuity was established, and the spark plug electrodes appeared normal. Continuity from the cockpit engine controls to the engine was confirmed. The throttle body, engine-driven fuel pump, and electric boost pump showed no evidence of a mechanical malfunction or failure. Although data from the electronic engine monitor confirmed that the engine rpm decreased to near idle and continued to decrease throughout the accident sequence, the reason for the partial loss of engine power could not be determined.

Text from the NTSB. Open the NTSB docket for ERA15LA197 for the full record.