Flight Maneuvers
According to memory data from the aircraft's GPS, the airplane executed steep 360-degree turns to the left and right before proceeding toward a practice area. During this transition, airspeed and altitude gradually decreased. A low cloud ceiling was present at the time. Witnesses reported hearing both engines "sputter, then quit" before observing the airplane clear a grove of trees, stall, and strike the ground. The landing gear was extended, and the flaps were in the approach setting. Propeller examination showed both propellers were in the low pitch and high rpm range, with little rotational signature.
Fuel System Examination
Examination of the fuel supply lines revealed only residual fuel in both lines. Individuals familiar with the chief pilot's routine during check rides stated that he always followed a specific procedure. This routine included turning on the boost pumps before performing steep 360-degree turns and turning them off after completion of the maneuver. The investigation identified that unguarded fuel shutoff switches are located adjacent to the boost pump switches. The circumstances of the accident are consistent with the fuel shutoff switches being inadvertently placed in the off position instead of the boost pump switches.
Probable Cause
Official findings determined that the pilot-in-training inadvertently shut off both engine fuel control valves, resulting in a loss of power in both engines. The pilot then failed to maintain control of the airplane, leading to a stall. Contributing to the accident was the chief pilot's inadequate supervision of the pilot-in-training.