THE Royal Air Force had no maintenance guidance for a vital fuel safety valve on its "workhorse" Puma helicopters, an inquest heard.

Upgrades and overhauls of the valves were only undertaken after a Puma crashed in Iraq in November 2007 killing two SAS soldiers and seriously injuring several others.

The valve should have stopped fuel spilling out of the Puma's engine and then catching fire, as it did in the Iraq crash.

But over two days of technical evidence and related cross-examination, the inquest into the deaths of Sgt John Battersby and Tpr Lee Fitzsimmons heard that checks on the valves were not then part of the Puma maintenance programme and hadn't been over the 30 or more year lifespan of the fleet.

This, the inquest heard, had now changed with each Puma having the valves checked and subject to a regular maintenance schedule - particularly where they were operating in desert conditions.

Senior RAF engineer Squadron Leader Michelle Casey said, in evidence, that with hindsight it was "surprising" that their was no maintenance of the valves.

Maintenance requirements were, the inquest heard, set by the Puma manufacturers and the Ministry of Defence.

In earlier evidence, Puma pilots on the ill-fated mission said they would have considered the helicopters unairworthy had they known of faults with the valves.

Tests on radio equipment that the pilots reported as unreliable showed the system worked but, as conducted, these tests could not account for intermittent faults, the inquest heard.

Medical evidence put to the inquest strongly suggested that both Sgt Battersby and Tpr Fitzsimmons were probably dead from the severe injuries they sustained in the crash by the time the fire took hold.

The inquest continues.