What happened
Following maintenance work performed on the left engine, the aircraft departed during nighttime hours. While the pilot was executing the base leg of the approach, the aircraft struck the ground in an inverted, nose-down position. Upon inspection of the wreckage, the propeller on the left engine was found in the feathered position.
Physical evidence at the scene indicated a significant mechanical failure within the engine. The number 5 cylinder had become detached from the engine, and the piston, along with its attached connecting rod, was discovered in the vicinity of the aircraft.
Findings
Investigations into the maintenance history revealed that several individuals had participated in servicing the aircraft. During the recent maintenance period, the number 1, 3, 5, and 6 cylinders had been removed and subsequently reinstalled. However, the number 5 cylinder had not been properly tightened during the reinstallation process.
Further analysis identified a lack of communication protocols at the maintenance facility. There was no established system to track or transfer information regarding completed tasks between different technicians. Additionally, it was noted that there were no FAA requirements for tracking such work progress in facilities operating outside of 14 CFR Part 121 or 14 CFR Part 145.