What happened
During cruise flight, the left engine of the airplane suffered a total loss of power. The damage sustained by the engine during this failure prevented the propeller from being feathered, which rendered the aircraft unable to sustain flight.
In response to the engine failure, the pilot performed an emergency landing in a field. As the aircraft was rolling out on the ground, the nose gear and left main gear collapsed.
The investigation
A post-accident examination of the failed engine showed that the piston and number four cylinder were missing from the engine case.
At the Safety Board's Materials Laboratory, investigators examined the left case and the associated fasteners. This examination identified fatigue cracking within the engine case, as well as in the through bolts and studs. Additionally, researchers noted that three of the six studs located around the number four cylinder were not recovered.