History of the Flight
The pilot and four passengers had flown from North Weald to Antwerp the previous day. On 25 July 2010, the pilot arrived at Antwerp Airport around 1300 hrs and completed customs and administrative tasks before conducting a pre-flight check, which revealed no faults. He started the engines at 1405 hrs and took off at 1415 hrs for the return flight to North Weald.
The aircraft initially climbed to FL50, then descended to 4,000 ft amsl for the transit across the English Channel. It further descended to 2,500 ft amsl approximately 10 nm south-west of the airfield. The pilot contacted North Weald Radio and descended to 1,500 ft amsl.
At about 5 nm from the airfield, with Runway 20 in sight, the pilot heard a "surging" noise. The right propeller rpm and manifold pressure indications fluctuated. He switched both electric fuel pumps on and set both mixtures to full rich. The fluctuations continued, so he switched the right fuel selector to the outboard tank. The engine stabilised briefly then cut out. The pilot increased power on the left engine, feathered the right propeller, and made a PAN call requesting priority landing.
Shortly after, the left engine began surging and its rpm and manifold pressure fluctuated. The pilot kept the left inboard tank selected; after several seconds, the left engine ran down. He feathered the left propeller, trimmed the aircraft for a glide speed of 120 kt, and continued towards the runway at 1.5 to 2 nm range and about 1,000 ft amsl.
The pilot tried lowering the landing gear but nothing happened; he decided to land on the asphalt runway with the landing gear retracted. He maintained a level attitude, allowed the speed to decrease, and the aircraft settled onto the runway. It decelerated rapidly and stopped on the 1,920 m paved surface. No one was injured; the pilot and passengers disembarked unaided via the rear cabin door. Touchdown was recorded at 1521 hrs.
Weather
The weather was good with no requirement for de-icing or pitot heat. The aircraft did not encounter rain en route or while parked overnight. The pilot reported a headwind of about 10 kt on the return flight.
Aircraft Examination
After the accident, the aircraft was raised on jacks, the landing gear extended, and it was moved for examination. The fuselage belly exhibited extensive skin and frame damage consistent with a landing on a hard runway with the gear retracted. Both propellers were feathered with blade tip damage and no evidence of rotation during impact.
The fuel selectors were positioned to draw from the left inboard and right outboard tanks. Firewall emergency shutoff valves were open; the cross-feed valve was closed. Fuel was drained from each tank: left outboard 4.8 USG, left inboard 0.1 USG, right inboard 0.9 USG, right outboard 0.1 USG.
The left inboard fuel gauge indicated empty; left outboard indicated ⅜ full. The right wing gauge was inoperative, remaining below the empty mark. No external fuel leakage was found on the aircraft or runway. Wing-mounted fuel filters showed no contamination.
The Hobbs meter reading after the accident was 1177.6; prior to the flight from North Weald it was 1175.1. This indicated 2.5 hours of running time on the right engine since refuelling, consistent with flight times (2.1 hours) and ground running (0.4 hours). The left engine ran for a similar duration.
Fuel Onboard
Prior to departure from North Weald, the pilot refuelled the aircraft. He had no means to determine the fuel quantity because the tanks could not be dipped and he believed the gauges were inaccurate. There was no aircraft technical log or documented fuel record. The pilot considered that the only way to be sure of the quantity was to fill the tanks completely.
After refuelling, the gauges indicated each inboard tank was only ⅔ to ¾ full, despite both the pilot and bowser operator confirming the inboard tanks were filled completely. The refuelling docket recorded 273 litres (72 USG). No fuel quality issues were found.
Before departure from Antwerp, the fuel gauges showed each inboard tank approximately ⅓ to ½ full. The pilot did not visually check the outboard tanks but stated the gauges indicated they were empty. There were no indications of fuel leaks during external checks.
It was normal practice for pilots to pay directly for fuel uplifted, with no procedure for compensation for unused fuel.
Engine Management
During cruise on both flights, the pilot adjusted the mixture to achieve peak EGT and then enriched slightly. He set 30 inches of manifold pressure and 2,400 rpm, consistent with about 70% power. The indicated fuel flow was 16-17 USG per hour per engine. Radar recordings confirmed a cruise speed of about 170 kt, which the Aircraft Flight Manual equates to about 75% power.
No fuel consumption figures other than those in the Information Manual were available. The manual gave cruise consumption of 35.6 USG/hr at 75% and 27.8 USG/hr at 65%, assuming leaning according to flight manual instructions (lean to peak EGT then further lean until a drop of at least 25°F EGT). Climb consumption was 56 USG/hr at 39.5 inHg and 2,400 rpm. Both the Information Manual and Flight Manual stated that performance may vary depending on equipment, condition, atmospheric conditions, and piloting technique.
The Flight Manual contained no idle fuel consumption data; the engine manufacturer indicated about 1.5 USG per hour per engine at idle.
Documentation
The pilot completed weight and balance charts for each flight. For the outbound flight from North Weald, he recorded fuel on board as 670 lbs (112 USG). For the return from Antwerp, he recorded 420 lbs (70 USG).
The pilot's navigation log showed a planned flight time of one hour per leg, with fuel consumption of 35.6 USG at 75% power. However, his weight and balance chart for the outbound flight indicated he calculated 42 USG, accounting for taxi and climb. The return plan showed the same, giving a total planned consumption of 84 USG. The inboard fuel tanks held 108 USG useable, leaving 24 USG reserve (about 40 minutes).
The pilot relied on an Information Manual for fuel calculations; no other documented fuel consumption figures were available.
Pilots operating the aircraft were requested by the owner to complete a 'Flight Report' form after each flight (details not specified).
Probable Cause
Fuel exhaustion due to higher than planned fuel consumption, resulting from a combination of factors.