A cockpit recording from an RAF Nimrod spy plane moments before it exploded in mid-air has been played to the families of the 14 men killed in the tragedy.

A cockpit recording from an RAF Nimrod spy plane moments before it exploded in mid-air has been played to the families of the 14 men killed in the tragedy.

The crew's conversation was calm and professional despite the increasing seriousness of the situation.

The audio recording ends at 11.15am on September 2, 2006, about two minutes before Nimrod XV230 exploded in a ball of flame.

Flight Lieutenant Douglas McKay was flying in a Harrier jet nearby. He saw two fires in the Nimrod's rear. About 90 seconds later, it was engulfed in a "massive, catastrophic explosion about twice the diameter of the aircraft's wingspan."

He told the Oxford inquest yesterday that the Nimrod was "totally destroyed before it hit the ground".

The craft exploded a few minutes after air-to-air refuelling near Kandahar because fuel leaking into a dry bay ignited on contact with a hot air pipe, the hearing has heard.

The crew had no way to tackle the fire and tried to make an emergency descent to the Kandahar air base, but at 3000ft the aircraft exploded.

The first section of the onboard audio recording is about the refuelling procedure.

An engineer tells Flt Lt Allan Squires, the captain: "We're full" and moments later, at 11.11am GMT, a fire alarm sounds. The engineer says: "I have a bomb bay fire warning."

Flt Lt Squires is then heard to say: "Crew captain - we have a bomb bay fire warning indication."

An officer says: "It's in the rear bay, there's smoke coming from it Rear bay smoke coming "

An engineer responds: "Yeah, I have an under-, er, an over-heated SCP supplementary conditioning pack, which could be the cause."

The SCP - installed to reduce heating caused by the plane's equipment- is thought to have caused the fire.

At 11.12am a crew member says: "We have smoke coming from the aileron bay and we've just had a lot more smoke coming from the aileron bay."

As the crew give more fire reports , the captain orders the aircraft to steer to Kandahar for an emergency landing.

At 11.13, the onboard audio recording captured the following: Air electronics officer (AEO): "Report from the bay."

Bay: "Fire in the bay, fire in the bay."

AEO: "Fire in the bay."

Captain: "Roger, descending."

Captain at 11.14: "OK, we'll put out a mayday please."

A mayday message is sent and repeated several times.

At 11.15, AEO says: "Further flames in the bay."

An engineer reports using a fire extinguisher: "Roger, further 10 sec burst into the bay."

Captain: "Just look at the runway direction please."

Co-pilot: "East west."

Captain: "See if you can get the weather for me please."

Engineer: "Second burst gone, there's more smoke coming up from the back."

Answer: "Roger"

Captain: corrupt speech Crew member: "Further report from the bay."

Answer: "From the bay, there's more sm smoke The tape ends abruptly and the plane explodes soon afterwards.

The last external radio message heard from the Nimrod, at 11.15, was: "Request runway in use? Vigil 34 descend at pilot's discretion, runway in use."

The 12 RAF personnel killed were Flight Lieutenant Steven Johnson, 38, and Flt Lt Leigh Anthony Mitchelmore, 28, both from Elgin, Morayshire; Flt Lt Gareth Rodney Nicholas, 40, from Forres, Morayshire; Flt Lt Allan James Squires, 39, Nairn; Flt Lt Steven Swarbrick, 28, Inverness; Flight Sergeant Gary Wayne Andrews, 48, Fochabers, Morayshire; Flt Sgt Stephen Beattie, 42, Flt Sgt Gerard Martin Bell, 48, and Flt Sgt Adrian Davies, 49, all from Forres; Sergeant Benjamin James Knight, 25, Inverness; Sgt John Joseph Langton, 29, and Sgt Gary Paul Quilliam, 42, both from Forres.

Lance Corporal Oliver Simon Dicketts, 27, of the Parachute Regiment, from Wadhurst, East Sussex; and Royal Marine Joseph David Windall, 22, from Hazlemere, Buckinghamshire, also died.

It was confirmed last night that the Nimrod aircraft which relatives were shown at the start of the inquest was a replacement, as the plane originally earmarked, from RAF Kinloss in Moray, developed a fuel leak.

The question of fuel leaks has been a major focus in the inquest, which continues today.