Boeing A75N1 N985SS accident near Santa Rosa, California

Probable cause

The partial loss of engine power due to fuel contamination and partially blocked fuel screens.

NTSB analysis

While joining up in formation flight with a second airplane, the pilot reduced engine power to slow his airplane. When he subsequently tried to increase the engine power, he noticed no response from the engine. The pilot stated that the engine was still running; however, the adjustment of the throttle control and the electric fuel boost pump did not alter the engine's power setting. The pilot performed a forced landing to a vineyard, and the airplane nosed over during the landing roll. Postaccident examination of the engine revealed that the main fuel system screen contained a fuzzy, spongy material along with other debris. The throttle body screen also contained small debris particles. Debris was also found in fuel that was removed from the lower fuel tank. It is likely that the debris within the fuel system restricted fuel flow to the engine and limited the power output. The source of the debris was undetermined.

Text from the NTSB. Open the NTSB docket for WPR13LA212 for the full record.