Decades-old debris inside an engine carburettor was very likely the cause of the crash that killed Royal Air Force pilot Squadron Leader Mark Long, an official military investigation has concluded.

The 43-year-old pilot died when his Supermarine Spitfire came down during a Battle of Britain Memorial Flight display near RAF Coningsby in Lincolnshire on 25 May 2024. The incident took place at 1.16pm, shortly after he took off to conduct a series of scheduled flypasts and a display.

A service inquiry report published by the Defence Safety Authority found that witness accounts and engine data aligned with what would be expected during fuel starvation. Investigators determined that foreign material had lodged inside the carburettor mechanism.

According to the report, the panel concluded that debris partially blocked the carburettor's lean metering jet. This restriction reduced fuel flow and created an overly lean mixture, cutting engine power and reducing thrust below the level required to keep the aircraft flying safely.

Chemical analysis carried out during the inquiry indicated that the debris responsible for the blockage had been present inside the system for decades. The aircraft, Spitfire MK356, was built in early 1944 at the Castle Bromwich Aircraft Factory in Birmingham, which was owned by the Morris Motors Company.

Investigators also looked closely at the pilot's restraint system, including the harness and associated structural components. The panel concluded that while the setup was critical to pilot survivability, its design was very likely an aggravating factor in the accident, recommending that modifications should be considered to enhance safety.

Following his death, Squadron Leader Long's family issued a statement through the Ministry of Defence, remembering him as someone who lived with unwavering passion, laughter, and dedication to his family. They said his talent for flying was clear to see and that his ability to connect with people was infectious.

Born in Bury St Edmunds, Mr Long graduated from initial officer training in 2003 and earned his wings on the Tucano at RAF Linton-on-Ouse. After serving as a Hawk instructor, he converted to the Harrier GR7/9 at RAF Cottesmore, becoming the last RAF Harrier pilot qualified to operate from an aircraft carrier.

He joined the Typhoon Force at RAF Coningsby in 2012, later becoming a display pilot in 2016 and instructing trainee pilots. His service also included quick reaction alert duties protecting UK airspace, the Falkland Islands, and Baltic air policing in Lithuania, alongside entering his fourth season with the Battle of Britain Memorial Flight.

The Defence Safety Authority stated that the inquiry's findings and safety recommendations have been published to inform both the military chain of command and the wider public to improve defence safety.

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