Amateur-built RANS S-12 N98ES accident near Gardner, Kansas

Probable cause

The pilot's inadequate airspeed control and the airplane’s exceedance of its critical angle-of-attack during the forced landing, which resulted in an aerodynamic stall. Contributing to the accident was the loss of engine power due to fuel starvation caused by contaminants in the fuel tank.

NTSB analysis

The pilot stated that, shortly after departure, the engine experienced a loss of power, and he maneuvered the airplane for a forced landing. A witness observed the airplane pitch up, stall, and roll into a spin before impacting terrain in a near-vertical attitude. A postaccident examination of the airplane found that fuel delivery to the engine was restricted by grease in the fuel tanks. It is likely that the engine was starved of fuel due to the grease contamination, which led to the loss of power. However, the pilot did not subsequently maintain the airplane's airspeed and angle-of-attack as he maneuvered for the forced landing, and the airplane experienced an aerodynamic stall.

Text from the NTSB. Open the NTSB docket for CEN15LA431 for the full record.