Beech H35 N653T accident near Monroe, Louisiana

Probable cause

The loss of engine power 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

The commercial pilot was conducting a maintenance test flight. According to Federal Aviation Administration audio files, the pilot reported to an air traffic controller that the airplane was experiencing an unspecified fuel problem. The engine then experienced a total loss of power, and the pilot conducted a forced landing, during which the airplane collided with a tree and then impacted a parking lot. A postaccident examination of the airframe, engine, and fuel system did not reveal any preimpact anomalies that would have precluded normal operation. A review of data obtained from the airplane's engine data monitoring system did not reveal any unusual engine readings before the loss of engine power.

At the accident site, fuel was drained from each wing tank and a fuel line leading to the engine; the fuel from the fuel line was orange. Testing of the orange fuel sample revealed the presence of silicon. The tank seals and lines were intact, and the source of the silicon could not be determined. No silicon nor any white powdery deposits (the expected combustion byproducts of silicon) were found on any of the engine components. The reason for the loss of engine power could not be determined.

Text from the NTSB. Open the NTSB docket for CEN14LA273 for the full record.