History of the Flight
The flight was intended to ferry the Europa XS, registration G-BYFG, from Fishburn Airfield near Durham to its base at Tatenhill near Burton-on-Trent. The aircraft had been at Fishburn for repair work following a previous landing accident in February 2008. After completion of repairs, taxi trials and a test flight were successfully undertaken, and the inspection and test flight for the renewal of its Permit to Fly were completed in March 2009.
The pilot, a 59-year-old commercial pilot with 2,150 total flying hours including 110 on type, was asked by the owners to conduct the flight as they were not current on the aircraft. One co-owner flew the pilot to Fishburn in another aircraft and assisted with preparations.
Prior to departure, the pilot taxied to the fuel bowser and remained seated. The fuel sight tube, located on the centre tunnel near the pilot's footwell, was difficult to see from his position. The co-owner stood beside the cockpit to observe the sight tube. An assistant added fuel, stopping when the level approached the top of the tube to avoid overflow. Fuel was carefully added until the level reached the top, which was taken to indicate a full tank. A total of 26 litres of Avgas was uplifted.
Pre-flight and pre-takeoff checks were completed satisfactorily. During power checks, the pilot selected the fuel selector to the other tank outlet to check supply from that part of the tank. Operation of the carburettor heat produced a small reduction in rpm but a temperature rise confirmed the system was operational.
In cruise, the pilot reduced power to match a slower following aircraft. After about 90 minutes, there was a sudden and significant loss of engine power. The pilot applied carburettor heat, selected the electric fuel boost pump on, and switched to the other fuel source, but none restored power. He adjusted throttle to maximize available power.
He declared a MAYDAY to East Midlands Radar and intended to land at Ashbourne airfield. Within minutes, the engine lost all power. He selected a field for a forced landing. As he descended, power cables made the field unsuitable, and no other suitable fields were within gliding range. During landing, the aircraft floated towards a tall hedge. The pilot flew through the hedge, which rapidly slowed the aircraft, and it came to rest upright in the next field.
The pilot suffered minor injuries and exited unaided. The aircraft sustained substantial damage including engine detachment. He turned off the master switch and fuel selector, then contacted East Midlands Radar by mobile phone. Emergency services attended, and the pilot was taken to hospital. The aircraft was recovered the next day and later taken to AAIB facilities for examination.
Aircraft Description
The Europa XS is a side-by-side two-seat homebuilt aircraft. Over 1,000 kits have been delivered, with several hundred completed and flying. It is often fitted with a Rotax engine, but installation of the Jabiru 3300A piston engine is approved by the Light Aircraft Association (LAA).
Fuel System
The aircraft had a single saddle-shaped tank behind the seats, placarded with a total useable capacity of 65 litres (56 main, 9 reserve). Main fuel is drawn from the upper part of one side; the other side serves as a small reserve. A sight tube on the centre tunnel indicates fuel quantity. The tube must be calibrated during construction. On G-BYFG, the tube was discoloured and hard to read. Graduation markings (20, 30, 40, 50) were visible behind the tube, but their significance was unclear. A line on the tube next to the '40' graduation was found, but its meaning was not established. During wreckage examination, water poured into the tank with aircraft level showed that the '40' graduation corresponded to only 20 litres, and top of tube corresponded to over 60 litres.
A metal calibration strip had been affixed beside the sight tube after fuel line replacement but was later found detached in a stowage pocket. When it became detached is unknown, and calibration accuracy could not be verified.
Fuel System Modification
In June 2007, under LAA inspector direction, fuel lines were replaced and an additional return line 'required for MOGAS usage' was installed. This modification was not approved by the LAA. The bleed return line was connected between the main fuel line upstream of the engine-driven pump and the reserve side of the tank. A restrictor was soldered into the T-piece. Placards indicated unleaded Mogas could be used, but the co-owner stated the aircraft was being prepared for Mogas use pending further testing.
Examination and Testing
On examination, no fuel was found anywhere in the fuel system or components, but given the time since the accident, this was not considered significant. The carburettor float bowl was free of debris and functioned normally during testing. Fuel filters contained small particles, not unusual. Only one filter had a required safety spring, but the element remained properly located. Disrupted pipes forward of the firewall were forcibly pulled from fittings when the engine detached.
The fuel system up to the point of engine detachment was free from leaks and capable of supplying fuel. No evidence of fuel staining indicated a leak. A flow test using the electric boost pump showed sufficient flow for all power settings.
A further test simulated the engine-driven pump with an electric pump. With the selector on RESERVE, flow continued until that side was depleted, then decreased. Selecting MAIN and boost pump restored flow but at a much lower rate. Air was being drawn in through the bleed return line from the empty reserve side. Blocking the return line restored normal flow.
Engine testing did not reveal any defects. The investigation could not positively determine the cause of the power loss, but the unapproved modification may have been a contributory factor.