What happened
During the climb to cruise altitude, the pilot of the aircraft reported that the left engine cowl assembly had separated from the plane. Onlookers at the scene observed the aircraft type exhibiting unstable flight characteristics, including heavy yawing and sputtering, while flying at a low altitude. Witnesses noted that the left engine had ceased operation and that the plane performed a steep right bank before obscured by trees and crashing. The single occupant of the aircraft, the pilot, was killed in the accident.
Findings
An investigation into the wreckage and the surrounding area recovered the left engine cowling approximately 1.8 miles away from the crash site. Investigators determined that the left propeller had failed to feather following the engine failure. The inspection of the cowling revealed that three primary eyebolt fasteners on the outboard side of the left upper cowl were in the unlocked position, and seven additional attaching studs were missing.
Records indicated that the cowling had been detached 16 days prior to the accident to facilitate the installation of an oil/air separator, and this flight was the first since that maintenance was completed. While the mechanic responsible for the maintenance work acknowledged that several cowl studs were missing and had informed the pilot, the pilot reportedly stated that he possessed replacement fasteners and intended to address the issue later.