What happened
On 1 August 2015, a Vickers Armstrongs Ltd. Spitfire IX, registration G-BRRA, departed from Runway 29 at Bigto Hill Airport, Kent, for a private flight. Shortly after the pilot retracted the landing gear and adjusted the engine power, the engine emitted a cough, followed by a significant reduction in power. The pilot observed flames emerging from the right-hand exhaust pipes.
Realising that the aircraft lacked sufficient energy to reach the runway, the pilot attempted to maintain enough airspeed to return to the airfield perimeter. While the reduced power was just enough to reach the airfield boundary, the aircraft could not be brought back to the runway. To avoid a stall, the pilot levelled the wings and landed on waste ground to the east of the airfield. During the landing roll, the aircraft struck a line of trees, causing the right wing to detach at the root. The aircraft subsequently spun and came to rest on its right side. The pilot sustained minor injuries.
The investigation
The AAIB examined the circumstances of the engine failure and the subsequent impact. A preliminary inspection of the Rolls-Royce Merlin 70 engine revealed a broken inlet valve spring in a cylinder within the right bank. This failure resulted in the induction flame trap being penetrated. While the full extent of the engine damage was not yet determined, the investigation focused on whether this mechanical failure was the primary driver of the power loss.