What happened
On 28 August 2004, a Socata TB10 Tobago, registration G-BOIU, departed from Runway 26 at Bournemouth International Airport for a private flight. Shortly after takeoff, the pilot notified Air Traffic Control of an engine problem and expressed an intention to return to the airfield for an immediate landing on Runway 08.
During the attempt to turn back, the aircraft entered a left-hand turn at a low altitude. The flight was observed by the tower controller to descend while in this turn. The aircraft crossed the airfield boundary, flew over the B3073 road, and struck a wooden fence at the entrance to an amusement park. The impact caused the aircraft to slide across a grass field and strike a hedge, which resulted in a substantial post-impact fire.
While the pilot and one passenger managed to escape the burning wreckage, the second passenger was unable to be rescued due to the intensity of the fire. The escapee passengers sustained severe burns and required medical evacuation. The aircraft was destroyed in the accident.
The investigation
Investigators from the AAIB examined the wreckage and analyzed radio communications. The investigation focused on the engine's performance and the pilot's decision-making process. Examination of the engine and propeller showed no definitive evidence of a pre-impact mechanical failure, though the possibility of carburettor icing could not be entirely ruled out due to the atmospheric conditions.
The investigation also reviewed the aircraft's flight controls and fuel system. While the fuel selector was found to be set to the left tank, the fire had destroyed much of the fuel system pipework, making it impossible to determine exactly when the valve was moved. The investigation noted that the constant-speed propeller could have masked the symptoms of a power loss, as the governor would attempt to maintain engine speed despite a reduction in power.
Findings
- The aircraft was operating in a controlled descent and turn at the time of impact.
- The pilot's decision to attempt a turn-back was influenced by a perceived loss of airspeed rather than an immediate total engine failure.
- The loss of engine performance was likely difficult to detect immediately due to the characteristics of the constant-speed propeller.
- The post-impact fire was severe, preventing the rescue of the third occupant.
- The aircraft's flight path was influenced by the pilot's need to maintain visibility of the landing area during the turn.