What happened
A flight plan was filed for a trip from Cardiff (Rhoose) Airport to Eastleigh Airport, with a planned continuation to Paris. The aircraft, carrying the pilot and six passengers, departed at 09:25LT. While cruising at approximately 5,500 feet, the pilot contacted London air traffic control to request clearance for the Southampton Zone.
Shortly after 09:50LT, the engines became unsynchronized, accompanied by significant vibration throughout the airframe. During this period, the port propeller ceased rotation, causing the aircraft to lose altitude. Although the pilot managed to restart the port engine once the aircraft reached an altitude of 200 feet, the plane continued to fly at a very low altitude and low speed over undulating terrain, passing near high-tension cables.
As the aircraft attempted to climb over a ridge, it descended into a heavily wooded region. During this phase, the aircraft banked left, causing the port wing tip to strike a tree. The momentum carried the plane another 400 yards through the treetops before the final crash. The accident resulted in one fatality (the pilot) and four serious injuries among the passengers.
Findings
Investigations revealed that the pilot had inadvertently shut down the port engine instead of the starboard engine, which was actually the unit experiencing a mechanical failure. While the port engine was restarted, the malfunctioning starboard engine remained running and sustained significant damage during the incident.
Technical analysis determined that the starboard engine's crankshaft had broken at the number 3 crankpin due to a fatigue crack originating from a plugged hole in the rear web. Evidence of heavy scoring on the crankcase components indicated that cylinders 1 and 2 remained operational after the initial failure. At the time of the accident, the crankshaft had been in service for 1,205 hours since manufacture, including 619 hours since its most recent overhaul.