What happened
During a scheduled competency and proficiency check, the chief pilot of the airline was conducting a training session with a newly hired pilot. Flight data from the aircraft's GPS indicated that the aircraft type performed several steep 360-degree turns to both the left and right. Following these maneuvers, the aircraft proceeded toward a designated practice area, though it experienced a progressive loss of both airspeed and altitude.
At the time of the accident, a low cloud ceiling was present in the area. Eyewitnesses reported hearing both engines sputter and subsequently fail. The aircraft was observed passing over a grove of trees before entering a stall and striking the ground. Upon inspection, the landing gear was found in the extended position, and the flaps were set to the approach configuration. Additionally, both propellers were observed in a low pitch/high RPM setting, showing minimal rotational movement. An examination of the engine fuel supply lines revealed that they contained only residual fuel.
Findings
Investigation into the engine failure focused on the operational procedures used during the check ride. The chief pilot typically followed a specific routine where, after completing steep turns, the trainee would configure the aircraft for landing and perform minimum control maneuvers. This routine involved toggling the boost pumps on before the turns and off upon their completion.
It was determined that the aircraft's fuel shutoff switches are located next to the boost pumps and lack guards. The evidence suggests that the accidental movement of the fuel shutoff switches to the off position instead of the boost pumps caused the loss of fuel flow to the engines.