Accident Overview
On 3 June 2001, at approximately 1444 hours UTC, a Bell P-63A-7BE Kingcobra (registration G-BTWR) crashed during an air display at Biggin Hill Airport, Kent. The aircraft was destroyed and the pilot, the sole occupant, suffered fatal injuries. The flight was a private display.
Aircraft Information
The Bell P-63A-7BE Kingcobra was a single-seat Second World War fighter aircraft with tricycle landing gear and a laminar flow wing. It was powered by one Allison V1710-117 piston engine driving a hydraulically controlled, four-blade constant speed propeller. The aircraft was manufactured in 1944 and had been completely overhauled after acquisition by the operator in 1991. It first flew after overhaul on 12 August 1994 and had accumulated 73 hours since then. The most recent annual inspection for the Permit to Fly renewal was carried out on 24 May 2001. The aircraft had flown two hours between that inspection and the accident flight.
Pilot Information
The pilot held an Airline Transport Pilot's Licence and was 43 years old. He had 7,730 total flying hours, including 13 hours on type. He had flown the Kingcobra since April 1998 and had displayed it on at least 10 occasions. He held a current Display Authorisation for a Category C aircraft, valid until September 2001. The pilot had completed 30 minutes dual in a Harvard, 25 minutes display practice in the Kingcobra on 1 June 2001, and the airshow display on 2 June 2001.
History of the Flight
Three American Second World War fighter aircraft were to perform a joint display on the second day of the airshow. The Kingcobra was designated as the third aircraft and was to break away after some manoeuvres to perform a display including vertical manoeuvres. The aircraft waited at the holding point for Runway 03 for 15 minutes before takeoff. After takeoff, they held west of the airport for three minutes before commencing the display. They ran in together, performed a loop and a half cuban eight, then the Kingcobra broke away.
One minute later, after a flypast along the display line at 220 kt, the Kingcobra pulled up into a rolling climbing manoeuvre. At the top, partially inverted, the pilot appeared to lose control and the aircraft entered an incipient spin. The pilot recovered, having lost considerable height, and continued the display. He then flew past the crowd from left to right, performed a wingover to the left, and returned past the crowd from right to left at 190 to 195 kt.
The aircraft went out of view for about 20 seconds, turning right through some 220°, before running in directly towards the crowd and pulling up into the first half of a loop. At the top, inverted, full nose-up elevator was maintained and substantial right rudder was applied. The aircraft yawed right and departed into an upright incipient spin. The nose dropped steeply, full nose-up elevator was maintained, and rudder returned to neutral. The aircraft did not recover and impacted the ground in a nose-down attitude at about 160 kt. An immediate fire was extinguished by the fire crew, but the pilot had suffered fatal injuries in the impact.
Video Evidence
Video recordings allowed reconstruction of most of the display sequence. The elapsed time from takeoff to accident was seven minutes. One unsuccessful manoeuvre two minutes before the accident resulted in a departure from controlled flight but the aircraft was quickly recovered. Manoeuvre entry speeds were calculated: 250–270 kt on entry to the first loop, 210–230 kt before the first loss of control, and subsequently never above 200 kt. On the crowd flypast before the final manoeuvre, speed was measured at 192 kt and engine speed at 2,750 RPM.
During the final manoeuvre, full up elevator was maintained throughout. When inverted over the top, a large input of right rudder caused yaw to the right. After departure into the incipient spin, rudder returned to neutral. There was some aileron movement during the dive and the aircraft rolled right before impact.
Wreckage Examination
The aircraft crashed in a confined area west of the runway, in a steep nose-down attitude on a heading of about 076°. The pitot tube on the left wing was embedded at 70°. The right wing impacted first with little ground slide. The front section was buried about one metre deep. The outer left wing and right fuel tank were detached about 13 metres from the main wreckage. An impact fire around the fuel tanks was extinguished. Both tanks still contained some fuel, with evidence of fuel spillage. The main wreckage was unburned apart from a small fire around the rear of the engine. Landing gear and flaps were retracted at impact. Propeller blades showed some rotational scoring but no tip damage.
Detailed examination at the AAIB facility revealed no evidence of mechanical failure within the engine. The propeller regulator and blade pitch change mechanism showed no evidence of malfunction. The regulator control lever was approximately midway between fine and coarse positions. No pre-existing disease or medical condition was found that could have contributed to the accident. Toxicological examination did not reveal any factors that might have influenced pilot performance. Carbon monoxide levels were insufficient to cause incapacitation.
Meteorological Conditions
Weather was good for display flying. Surface wind was north-westerly at 10 to 12 kt, visibility greater than 10 km, broken cloud at 1,500 feet, air temperature 13°C.