Mystery deepens over Hercules crash

New questions emerged today over whether the downed RAF Hercules was shot down or destroyed by an on-board explosion.

Military experts believe the plane should not have been flying low enough for a low-technology terrorist missile to have reached it and some have suggested a bomb may have been planted on the flight.

Another possibility is that some volatile equipment on the plane exploded halfway through its flight from Baghdad to the US airbase at Balad.

The "effective range" of shoulderlaunched surface-to-air missiles is between 5,000 and 10,000 feet, although it is possible that a freak missile could get higher, said an RAF source.

The flight, which some sources say was at least 15,000 feet up when it exploded, came down 20 miles from Baghdad airport.

Any normal transport flight would be flying at a height of at least 20,000 feet, probably higher, by the time it reached this point in its journey, precisely because of the risk of missile attack.

The few civilian flights from Baghdad climb sharply immediately above the airport for exactly the same reason.

There were also questions about the reason for the flight, with the number of people on board and the timing of the mission both being viewed as suspicious by military analysts.

RAF sources have also questioned the description of the flight by the chief of the air staff, Air Chief Marshal Sir Jock Stirrup, as "routine".

"He is not lying - an operational flight is a term that can cover a number of possibilities - but if it was shot down, as is being claimed, it would need to have been flying far lower than you would expect for a straightforward transport flight," said one RAF source.

"It would have needed to have a good reason for being at that level.

"The other suspicious thing to me is the timing of the flight. If it was truly routine, it would probably not have been flown at dusk on election day, the most dangerous time you can possibly think of."

The fact that the downed Hercules worked for 47 Squadron, closely associated with special forces, has led to suspicions that it was either on, or returning from, some sort of mission connected with the elections, such as surveillance or communications interception.

"Nine crew is an awful lot, even for a special forces Herc," said the RAF source. "There are many possible explanations but one is that they had some special equipment on board."

There are also some questions about the quality of the downed aircraft's "defensive aids systems" equipment designed to repel missile and other attacks.

It is not known whether the plane was an old version of the Hercules or a newer one which is known to have had difficulties with its infrared defensive mechanisms.

The questions arose as terrorists tried to turn the downing of an RAF Hercules into a propaganda coup.

Arabic television channel Al-Jazeera is repeatedly showing footage supplied to it by one rebel faction claiming to show the moment the plane was shot down with the loss of 10 British lives.

The video shows a button being pressed before cutting to a shot of a missile streaking into the sky.

The footage does not show the plane in flight or the moment of impact but instead moves onto a shot of a huge fireball.

The next images are of extensive wreckage apparently belonging to a Hercules plane.

The MoD has declined to comment on the film but military experts have dismissed the tape, handed to Al-Jazeera by the 1920 Revolution Brigades, as largely faked. While the wreckage does appear to be from a Hercules, the footage of it is shot in daylight, though the attack happened at dusk.

There is also doubt over the images of an explosion. The plane came down in a flat marshy area without the palm trees which appear in the foreground of the fireball.

Andrew Brookes, of the International Institute for Strategic Studies, said: "I think it is a genuine Hercules crash, with the other bits superimposed on it. It is possible some one has decided to cash in and produce a video."

Tim Ripley, defence analyst at the Centre of Defence and International Security Studies, added: "The rebels have not shot down any big planes before, so it's not as if they'd be recycling old footage of wreckage. But the first bit looks of a more propaganda nature."

Sir Jock said the C-130 Hercules had been transporting nine RAF personnel and one soldier on a "routine operational flight" when it crashed on Sunday afternoon.

It is understood at least one person on board was a member of the SAS.

He said: "I am aware that there is a great deal of speculation about what caused that crash, not least because of the video, purporting to be of a missile shooting down an aircraft.

"We have to find out the facts but this is going to take some time."