What happened
On 2 July 2005, a Pulsar kit-built aircraft, registration G-CCBZ, was participating in a group flight from Deanland Airfield, East Sussex, destined for the PFA Rally at Kemble. Shortly after departing from Runway 26, the aircraft reached an altitude of approximately 300 ft agl when the engine made an abrupt noise and ceased functioning.
The pilot attempted to restart the engine, including the use of the starter, but was unsuccessful. Realising a forced landing was necessary, the pilot identified the only suitable nearby field, despite the presence of a tall crop. During the descent, the pilot trimmed the aircraft for landing at approximately 15 and 0 ft agl. As the aircraft entered the oilseed rape crop, it experienced a rapid deceleration and a nose-down pitch. The aircraft came to a halt within a few metres of the initial contact. The impact caused extensive damage to the fuselage and resulted in the separation of the nose landing gear, though no injuries were sustained by the pilot.
The investigation
Investigators examined the engine and fuel system to determine the cause of the power loss. The pilot suspected fuel starvation and subsequently inspected the two carburettor float bowls. Both bowls were found to contain sediment. The larger particles identified were small flakes of red paint, which were consistent with the material found in the fuel cans used to refuel the aircraft.
Further technical examination of the fuel system revealed that the replaceable element within the Purolator fuel filter assembly had not been fully secured. This allowed the element to move or 'rock' within its housing, creating a path for unfiltered fuel to bypass the filter and enter the engine. Additionally, it was noted that the fuel supply to the engine primer is drawn from a tank sight glass, which lacks filtration.