NATHAN REES

A spy plane which crashed in Afghanistan killing 14 servicemen should not have been passed safe to fly because of a "fundamental flaw" in the aircraft fleet's design, an inquest heard yesterday.

A senior RAF officer admitted mistakes were made during a hazard assessment which could have identified the fault that caused the explosion which downed the ageing Nimrod plane.

Air Commodore George Baber said had they known then what they knew now the Nimrod fleet would not have been deemed airworthy.

The hearing at Oxford Coroner's Court had previously been told the tragedy was caused by fuel leaking into a dry bay and igniting on contact with a hot air pipe. The Air Commodore said having fuel couplings in the same compartment as a hot air pipe was a "fundamental design flaw".

The 37-year-old Nimrod exploded minutes after undergoing air-to-air refuelling near Kandahar on September 2 2006. The crew had no means of tackling the initial fire and so were forced to attempt an emergency descent to the air base, but at 3000ft the aircraft exploded into flames.

Air Commodore Baber told the inquest that he led an Integrated Project Team (IPT), who together with BAE systems, carried out a comprehensive hazard analysis of the Nimrod plane before the Afghanistan crash.

He said the possibility of the explosion in the dry bay was graded as "improbable" - one of the lower categories. But he admitted it should have graded higher which would have then warranted further action.

He told the inquest: "At the heart of this was a fundamental design flaw. We failed to catch that design flaw."

The inquest had earlier heard relatives of the men killed, 12 of whom were from Scotland, were shown a replacement aircraft after the one they were due to see suffered a technical fault. When the hearing started last week, they were taken to RAF Brize Norton in Oxfordshire to inspect a Nimrod which was flown from RAF Kinloss.

The court heard it was replaced after the original aircraft they were due to see suffered a "nose-wheel hydraulic jack failure".

The inquest continues.