Cubcrafters Inc CC11-160 N111JW accident near Milesville, South Dakota

Probable cause

Fuel starvation and a subsequent loss of engine power for reasons that could not be determined because a postaccident examination and a test run of the engine did not reveal any anomalies. Contributing to the accident was the pilot’s failure to maintain airspeed after the loss of engine power, which resulted in an aerodynamic stall and a hard landing.

NTSB analysis

The private pilot was conducting a personal flight and reported that the airplane had been "topped off" before takeoff. Due to a stronger-than-anticipated headwind en route, he decided to divert to an intermediate airport to add fuel so that the airplane would have an adequate fuel reserve. Shortly afterward, while the airplane was in cruise flight, the engine "abruptly stopped, [with] no coughing or sputtering." The pilot attempted to determine the cause of the problem. He noted that the fuel selector was set for both tanks and that each tank was about one-quarter full. The pilot also attempted to restart the engine but was not successful; as a result, he executed a forced landing to an open field. The pilot noted that the airplane's airspeed might have decayed on final approach to the field, resulting in an aerodynamic stall and hard landing.

Data from the airplane's avionics system indicated that engine performance was normal until about 15 minutes before the accident. At that time, the fuel flow varied over a 4-minute period. Afterward, the fuel flow returned to normal, and the engine's performance appeared stable. However, about 5 minutes before the accident, the fuel flow began to vary again and ultimately decreased to zero. The corresponding engine parameters also decreased at that time, which was consistent with a loss of power.

The engine data revealed that a loss of fuel flow to the engine precipitated the loss of power. However, a postaccident examination and a test run of the engine did not reveal any anomalies consistent with a loss of engine power. Specifically, the engine test run demonstrated operation of the engine, and no airframe fuel system obstructions or evidence of fuel leakage were observed. In addition, the fuel consumption for the accident flight was about one-half of the total usable fuel capacity, which excluded fuel exhaustion as a cause for the loss of engine power.

Text from the NTSB. Open the NTSB docket for CEN17LA265 for the full record.