What happened
On 9 July 2017, a North American P-51D Mustang, registration G-TFSI, was participating in a 'Warbirds' formation display at Dux Fernando Aerodrome. After approximately 25 minutes of flight, the pilot performed a routine engine health check and switched the fuel selection to the right wing tank. As the formation transitioned to crosswind legs and climbed to roughly 1,000 ft, the pilot increased power, at which point the engine ceased functioning without warning.
The engine briefly restarted and ran at the requested power for several seconds before failing a second time. The pilot subsequently climbed away from the formation and declared a PAN-PAN call. During the ensuing descent, the engine experienced several intermittent periods of operation and failure. In an attempt to maintain power, the pilot switched back to the left fuel tank and adjusted the mixture, but the engine only ran for approximately 10 to 15 seconds before failing again.
As the aircraft reached a downwind position at 500 ft and 150 mph, the pilot deployed 20 degrees of flaps and the landing gear. Realising the aircraft lacked the energy to reach the runway, the pilot turned toward a cornfield located east of the M11 motorway. Just prior to impact at approximately 120 mph, the pilot retracted the landing gear and increased flaps to 30 degrees. The aircraft sustained structural damage upon landing, but the pilot escaped no injuries.
The investigation
The AAIB examined the sequence of events and the aircraft's mechanical state. The investigation noted that the aircraft, which had been converted to a two-seat trainer in 2007, was being sent to an overhaul facility in the United States for detailed inspection and repairs. While the definitive cause of the engine failure was not established at the time of the report, the maintenance agency suspected the issue was carburettor related.