Failure of a vital electronic system on both an RAF Tornado and a US missile battery contributed to a fatal "friendly fire" incident in Iraq.
A Tornado was hit by a US missile in Iraq
Tornado crew Flt Lt Kevin Main and Flt Lt David Williams were killed when the Patriot missile downed their aircraft.
Electronics which identified the Tornado GR4, based at RAF Marham in Norfolk, as "friendly" had failed, an RAF board of inquiry has found.
The missile battery then misidentified the plane as an enemy rocket.
In a written ministerial statement, defence minister Ivor Caplin said there were several contributory factors to the accident in March 2003.
These included the failure of the Tornado's "identification friend or foe" (IFF) system.
Other factors included the "wide classification criteria" for anti-radiation missiles programmed into the Patriot system.
However, the inquiry also found that the training, doctrine and rules of the
engagement of the American' Patriot missile battery - as well as the
technology used - all contributed to the accident.
It painted a picture of inexperienced US troops, heavily reliant on technology
to make decisions, but lacking crucial equipment which could have helped them
identify the Tornado as a friendly aircraft.
Mr Caplin said: "Like most aircraft accidents, no single cause was to blame.
"The board of inquiry has established the causes of this tragic accident and has highlighted the various factors that contributed to it. The board's recommendations are now being implemented."
The Tornado was brought down on March 23 last year close to the Kuwait border as it returned from a mission over Iraq.