Amateur-built CHRISTEN EAGLE-II N88CE accident near Seward, Nebraska

Probable cause

The pilot’s inadvertent pulling of the mixture control lever on takeoff, which shut down the engine.

NTSB analysis

The flight instructor, who was seated in the front seat, was giving the private pilot, who was seated in the rear seat, a check-out in the single-engine biplane. The engine lost power on takeoff, and the airplane impacted a field. Examination of the airplane and engine revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation; however the mixture control lever, which was located below and to the left of the rear-seated pilot's left knee (there was no mixture control in the front seat), was pulled out about 2 inches. The lever should have been full forward during takeoff. The propeller control was situated directly below the mixture control and found in the full forward position. The propeller control lever is usually adjusted by the pilot after takeoff. Although the mixture and propeller control levers were color-coded, it's possible that the 6'5" private pilot's left knee blocked his view of the controls due to his size and the small cockpit. The mixture control knob was slightly larger than the propeller control knob, but both were similar in shape. It is possible that the pilot thought he was adjusting the propeller control rather than the mixture control on takeoff and inadvertently shut off fuel to the engine. Postaccident examination of the mixture control cable from the cockpit to the engine revealed it moved freely and there was no evidence it had been moved during impact.

Text from the NTSB. Open the NTSB docket for CEN11FA616 for the full record.