Laura May

A Royal Air Force engineer said yesterday he "should have been told" about signs of fuel leaks in an aircraft which exploded in mid-air, killing 14 servicemen.

The 37-year-old Nimrod XV 230 spy plane was engulfed in a ball of flames shortly after undergoing air-to-air refuelling while on a secret mission in Afghanistan. All 14 men on board were killed when the plane crashed near Kandahar on September 2, 2006.

The 12 RAF personnel who died were all from Scotland while Lance Corporal Olive Simon Dicketts, 27, from the Parachute Regiment and Royal Marine Joseph David Windall, 22, were also killed.

Oxford Coroner's Court, where an inquest into the deaths is being held, heard a series of fuel leaks had been reported throughout the Nimrod fleet.

A number of crews had noted fuel leaking into the fuselage after air-to-air refuelling before the crash in 2006.

Some of the aircraft were "blowing off" fuel and air through a special safety valve as the tanks were filled and the highly-inflammable fuel had been found puddled in the bomb bay and dripping off the undercarriage.

The RAF continued to refuel aircraft in the air after the tragedy but two more incidents involving fuel leaks led to the practice being suspended, the court heard. Sergeant Mark Wallington, the ground engineer who oversaw repair and maintenance work on the Nimrods in Afghanistan, said he had not been told about these incidents.

He said he knew the Nimrods would leak fuel from the wing tanks but not from the tanks in the fuselage, where the leak would be more serious, until after the accident.

Sgt Wallington added that he did not know the XV 230 had "blown off" fuel on two recorded occasions before the crash. "I think I should have been made aware. You like to know everything that is going on," he said.

"The blow off is a safety feature of the aircraft so it is not an actual fault so it might not be considered a fault to be reported."

However, he added: "I should have been told when fuel was found having escaped from the system."

An RAF Board of Inquiry (BoI) into the loss of the plane found that ageing components and a lack of modern fire suppressants were among the "contributory factors" which led to the accident.

The deaths of the servicemen was the heaviest loss of life suffered by British forces in a single incident since the Falklands War. The BoI found the most probable cause of the crash was an escape of fuel during the air-to-air refuelling, either as a result of an overflow or a leakage from the aircraft's system.

The fuel flowed back into a dry bay near the aircraft's No 7 fuel tank and ignited after coming into contact with an exposed hot air pipe.

With no means of attacking the principal fire, the crew had to attempt an emergency descent to the Kandahar airbase, but at 3000ft the aircraft was seen by a RAF Harrier pilot to explode in a ball of flame - just six minutes after the blaze broke out.

The inquest continues.