What happened
The pilot was operating the aircraft during a dark night under gusty wind conditions. Shortly after liftoff, the airplane veered sharply to the left. In an attempt to maintain a somewhat level attitude, the pilot applied full right rudder and aileron. While maneuvering to return to the airport, the aircraft flew through the tops of trees before colliding with the ground.
The investigation
The investigation focused on the configuration of the aircraft and its mechanical state. Investigators found that the landing gear was in the DOWN position and the propeller on the left engine had not been feathered. No mechanical anomalies were identified in the engine or airframe that would have prevented flight.
Regarding the cockpit controls, the landing light switches were found in the ON position, while the left engine magneto switches were in the OFF position. It was determined that the self-erecting springs on the magneto switch guard cover were broken, which allowed the guard cover to obstruct the landing light switches instead of protecting the magneto switches.