History of the Flight
On 6 July 2023, a Grumman FM2 Wildcat, registration G-KINL, was one of 13 historic aircraft participating in a fly-in and static display at the Heveningham Country Fair, held at Heveningham Hall Estate in Suffolk. The aircraft, powered by a single Wright Aeronautical Corp CT7-9B piston engine, was operated by a private pilot holding a Commercial Pilot's Licence. The pilot, aged 63, had 4,238 hours of flying experience, but only 2 hours on type.
The fair was attended by approximately 35,000 members of the public over two days. Three grass runways were available: 03/21, 06/24, and 15/33. Runway 06/24 was designated for the concours fly-in and flying display, used primarily by vintage aircraft.
The pilot departed from Duxford Airfield at about 1530 hrs with 102 US gallons of fuel. A Rallye Minerva with two ground crew flew ahead to assist with parking. The pilot flew a local flight prior to departure to refamiliarize with the aircraft.
Accident Sequence
Upon arrival at Heveningham Hall at about 1600 hrs, the pilot of G-KINL allowed the Minerva to land first. The Minerva pilot reported the runway was fine. G-KINL then conducted a low pass to assess the runway and approach, then positioned for landing on Runway 24. The pilot performed a three-point landing with the tail wheel about one foot off the ground, just before the threshold, at an approach speed of 85 knots. The initial landing roll was straight and under control with the throttle closed.
As the pilot began planning for taxiing, he noticed the tail rising. He applied full back stick, but the tail continued to rise. The aircraft nosed over and came to rest inverted approximately 96 meters from the touchdown point. The pilot braced for impact, leaning forward and low in the cockpit. Once inverted, the pilot remained conscious, suspended in his harness. Fuel leaked into the cockpit. He turned off the electrical system, removed his helmet, and broke through the canopy's Perspex to create an exit. Ground crew from the Minerva arrived and helped extricate the pilot, who was then taken to hospital by air ambulance.
Pilot's Comments
The pilot, an experienced vintage aircraft pilot with a Display Authorisation and over 1,800 hours on Spitfires, had landed at the fair in previous years in other vintage aircraft. He noted that the Wildcat's mainwheel tyres were narrow and inflated to about 100 psi. Prior to departure, he spoke with a representative from Heveningham Hall who stated the runway had been driven and was serviceable. No mention was made of the runway being potentially soft. The pilot commented that if such information had been provided, he would have considered it.
Airstrip Information
Runway 06/24 was located in a field normally used for pastoral farming, with about 6 inches of topsoil over heavy brown clay. The field was approximately 115 ft above mean sea level. The surface of the runway had a solid crust on top of a softer sub-soil, which is believed to have caused the aircraft's wheels to dig in and initiate the nose-over. The following day, two Spitfires landed on Runway 15 without incident; one pilot noted that the surface appeared solid and did not leave indentations when a shoe heel was dug in.
Meteorological Conditions
An aftercast from the Met Office indicated that rainfall in the local area over the previous four weeks ranged from 16.6 mm to 35.4 mm, with increased rainfall in early July. On 4-5 July, 30.0 mm fell at Tibenham, 15 nm away. No precipitation was recorded on the accident day. Conditions were fine with light winds from the southwest at 5-10 kt, temperature of 21°C, and good visibility. Local residents noted significant rainfall two days prior, followed by dry, sunny days. At Duxford, no rain fell in the week before the accident, leading the pilot to expect similar conditions at Heveningham Hall. At Wattisham, 21 nm southwest, temperatures reached 21°C the day before and 26°C on the day of the accident.
Investigation
The AAIB conducted a field investigation. The event organisers planned to implement additional operational coordination and risk management measures for future events.