Background
The aircraft departed Dunkeswell Airfield for Retford (Gamston) Airfield with three passengers, two of whom held flying licences. The flight was uneventful. After an hour on the ground, it departed with two passengers for Enstone Airfield, also without incident. The pilot reported visually checking the fuel tanks before departing Enstone and noted 390 litres (103 US gallons) on board, approximately half in the wingtip tanks.
Flight Sequence
After about an hour on the ground at Enstone, the pilot conducted power checks and taxied to Runway 08 for the return flight to Dunkeswell with one passenger. During the takeoff run, the left engine stopped, and the aircraft veered left before stopping. The pilot later recalled seeing birds in the climbout area, which was a factor in the abandoned takeoff. The aircraft taxied to an area outside the Oxfordshire Sport Flying Club, where the pilot attempted to restart the left engine. During these attempts, the right engine also stopped. The right engine was restarted, and after several attempts, the left engine started, emitting white and black smoke. Once running smoothly, the pilot taxied to Runway 08 threshold.
Accident
The takeoff run sounded normal, and the landing gear retracted at approximately 200 ft agl. A video recording captured the climbout. The aircraft initially climbed in a right turn; after 10 seconds, the wings levelled, the aircraft descended, and disappeared behind a tree line. After five seconds, it appeared flying west over buildings east of the disused runway at low height in a slightly nose-high attitude. The right propeller rotated slowly, left rudder was applied, and the aircraft yawed right. The left engine ran at high rpm, and the landing gear was extended. The aircraft turned right and was last seen flying northwest. The video cut away for 25 seconds; when it returned, a plume of smoke rose from buildings north of the runway.
The pilot reported that the right engine lost power during a right climbing turn. He recovered to level flight and selected the right fuel booster pump; the engine recovered power. He decided to return to Enstone. Abeam the Runway 08 threshold, the right engine stopped. He feathered the propeller, but single-engine performance was insufficient to climb or manoeuvre, so he selected a ploughed field north of Enstone for a forced landing. During the approach, the left engine produced only about 57% of maximum power, preventing the pilot from reaching the field. The aircraft crashed into farm buildings. An immediate fire ensued. The pilot and passenger escaped through the rear cabin door. The pilot sustained minor burns; the passenger sustained burns, a fractured vertebra, impact injuries to the chest, and lacerations to the head, and was taken to John Radcliffe Hospital in Oxford.
Investigation
The pilot and passengers reported both engines operated satisfactorily on the two prior flights. Maintenance 25 and 5 flying hours before the accident found no problems, and the power checks at Enstone were satisfactory. It is therefore unlikely that a fault on both engines caused the left engine to stop during the aborted takeoff and the right engine to stop during the climb. The aircraft was last refuelled at Dunkeswell, with no reports of fuel contamination, making contamination unlikely. The pilot reported sufficient fuel onboard, evidenced by the intense fire from ruptured tanks. With sufficient fuel, the most likely cause of both engine stoppages was a disruption in the fuel supply between the tanks and engine fuel control units. The reason for the disruption could not be established, but the fuel system design is more complex than in many light twin-engine aircraft.