What happened
During an instrument flight rules (IFR) flight, the aircraft climbed to 4,000 feet MSL while operating in overcast conditions. The flight then encountered severe turbulence, which triggered a rapid descent at a rate of 3,000 feet per minute. During this period of instability, the right passenger door and the left emergency exit separated from the airframe.
The separation of these components caused significant damage to the wing surfaces and the right engine nacelle. The pilot responded by pulling up abruptly to level the wings. The aircraft broke out of the overcast layer at 2,500 feet MSL with the wings level and the aircraft under control. During the encounter, the electrical power was lost. Despite the loss of power, the pilot successfully navigated the aircraft back to the airport, where it landed and taxied to parking without further incident. All occupants were not injured.
The investigation
Post-flight inspection revealed that the right wing was crushed at the engine nacelle and the nacelle itself was dented. Both wings exhibited distortion and wrinkling on both the upper and lower surfaces.
The pilot indicated that the passenger door may not have been fully latched prior to flight. Additionally, the pilot noted that during the turbulence, his leg struck the master switch, which resulted in the loss of electrical power.