Accident Overview
During cruise flight in a level six thunderstorm over the Atlantic Ocean, the pilot reported that the airplane's gyro had failed. Subsequently, the airplane began a left turn and disappeared from radar. The airplane and its occupants were later located on the ocean floor approximately 48 days after the accident.
Flight and Weather
The pilot had received a weather briefing from flight service station (FSS) records regarding the conditions along the intended route. The thunderstorm encountered was classified as level six, indicating severe intensity. The cause of the gyro failure was not determined.
Wreckage Recovery
Investigation revealed that the airplane had broken apart in flight. The outboard section of each wing and the tail section were not recovered. Additionally, the airplane's pneumatic system was found destroyed.
Probable Cause
The official probable cause of the accident was the pilot's failure to maintain aircraft control. Factors contributing to the accident were the presence of a level 6 thunderstorm, loss of gyro's for an undetermined reason, and the pilot's poor weather evaluation.