Flight Preparation
Pilot B arrived at Biggin Hill Airport, Kent, at about 1100 hrs for a planned flight to Pau, France. At about 1130 hrs, he helped tow the aircraft from its overnight parking position on the Southern Apron to a nearby handling agent. A member of the handling agent's staff observed Pilot B performing an external pre-flight check. Pilot B also requested a weather printout from another staff member. Pilot A arrived at about 1145 hrs and joined Pilot B at the aircraft. Witnesses noted nothing unusual in either pilot's demeanor.
Three passengers arrived at the handling agent at about 1300 hrs and waited in a lounge while their bags were taken to the aircraft and loaded into the nose baggage hold. A handling agent who later escorted the passengers to the aircraft reported that Pilot B met them outside. After boarding, the agent heard Pilot B announce a safety brief, after which he closed the aircraft door.
Takeoff and Witness Observations
Pilot A called for engine start at 1317 hrs and requested taxi at 1320 hrs, receiving clearance to taxi to holding point A1. At 1331 hrs, ATC cleared the aircraft to line up on Runway 21, and at 1332 hrs, cleared it for takeoff. Both clearances were acknowledged by Pilot A. The tower controller observed the takeoff and stated that everything appeared normal.
One minute after takeoff, at 1334 hrs, the crew made a transmission to ATC. Numerous witnesses reported seeing the aircraft over a built-up area about 2 nm north-north-east of Biggin Hill Airport, flying low over playing fields and houses. Witnesses reported that the aircraft maintained a normal attitude, though some said the landing gear was up and others said it was down. Some described a nose-high attitude and a banking maneuver away from houses just before the crash. Witness accounts varied regarding engine noise: some reported no engine noise, while others described a loud noise as if the engines were at high thrust. Two witnesses heard a pulsing, intermittent noise.
Sequence of Events
After flying at an extremely low height over several houses, the aircraft's left wing struck a house bordering a small area of woodland. The aircraft then impacted the ground between that house and another, catching fire. There were no injuries to anyone on the ground, but all occupants on board were fatally injured.
Probable Cause Findings
The investigation identified the following contributory factors: 1. It is probable that a mechanical failure within the air cycle machine caused a vibration, leading the crew to attempt a return to the departure airfield. 2. A missing rivet head on the left engine fuel shut-off lever may have resulted in an inadvertent shutdown of that engine. 3. Approximately 70 seconds before impact, neither engine was producing thrust. 4. A relight attempt on the second engine was likely initiated before the relit first engine reached idle speed, leaving insufficient time to develop enough thrust to arrest the aircraft's rate of descent before ground impact.