What happened
During the flight, the pilot reported maintaining an altitude of 6,000 feet, but subsequent communications ceased. Radar tracking indicated that after five minutes of steady cruise, the aircraft's ground speed began to decrease. As the speed approached 85 knots, the aircraft type performed a sharp left turn, causing the speed to drop further to 74 knots, at which point radar contact was lost.
Eyewitnesses observed the aircraft experiencing engine sputtering and intermittent power loss. While the engine was seen to restart and briefly initiate a climb with near full power, the sound of an impact was heard shortly thereafter. The accident resulted in five fatalities.
Findings
Investigations into the mechanical failures revealed significant issues with the fuel systems of both engines. The fuel servo for the left engine was found to be obstructed by dirt and corrosion, preventing necessary fuel flow. Additionally, the fuel strainer for this engine had been installed in the reverse direction, which permitted unfiltered fuel to reach the engine components. The fuel servo for the right engine also exhibited signs of contamination and corrosion.
Further inspection of the left propeller showed that it had not been feathered and showed no evidence of rotation under power. It was also determined that the aircraft was not in compliance with its required annual inspection requirements. The primary cause of the engine failure was contamination and improper installation of the fuel strainer.