What happened
The pilot planned a VFR flight at 1,000 feet AGL over hilly terrain. During the flight, the pilot reported that climb performance was noticeably low and observed smoke coming from the left engine. Upon entering a mountain pass, the pilot found it impossible to find an exit through the high terrain. In an attempt to maneuver away from the hills, the pilot executed a sharp turn.
Witnesses observed the aircraft flying at a low altitude. They reported that the airplane began a left turn and then proceeded straight down, nose first.
The investigation
An examination of the left engine was conducted following the accident. Investigators found one non-functioning magneto; however, no other issues were identified that would have prevented the engine from operating.