The errors committed by the crew of the Awacs plane - monitoring all air activity over northern Kurdistan on 14 April - include identifying the US Blackhawk helicopters as friendly but not telling the pilots of the F-15 jets who shot them down with the loss of 26 lives.
A Pentagon report last month revealed an extraordinary litany of mistakes made at all levels by the US Air Force officers in charge of the air exclusion zone in Iraq. One of the F-15 pilots had a droopy eyelid that made it difficult for him to tell the difference between light brown Iraqi and green-black US helicopters. Both F-15 pilots were briefed before taking off about everything - including the situation in Rwanda - but not about the fact that two of their own helicopters would be in the air.
The most mysterious aspect of the disaster is the inaction of the Awacs commander and his crew during the interception. The commander had only flown one mission in the previous three months and was not, under Air Force regulations, qualified to fly on the day of the accident.
The four crew of the Awacs who may face court martial have not been identified. It is not known if they are the same four who refused, on the advice of their lawyers, to answer questions put by the Air Force investigators. The final decision on the court martial will be taken by Lieutenant General Steve Croker, the commander of the Eighth Air Force, while a separate review board will make recommendations about what action is to be taken against the F-15 pilots. Three senior officers in overall charge of operations in the area have been relieved of duty.
A video of a radar screens on the Awacs (Airborne Warning and Control System) shows one of the helicopters correctly sending its Identify Friend or Foe signal which appears as a green square. Despite this none of the four Awacs crew members talking to the F-15s by radio told them that the Blackhawks had identified themselves. Shortly afterwards the F-15s said they were 'engaged' and then that they had 'splashed' or shot down the helicopters, killing 15 Americans and 11 others including two British officers.
Although their planes were crammed with technical devices able to see everything within a 300-mile radius, the Awacs crew deferred to the lead F-15 pilot, who believed, wrongly, that his wingman had also identified the helicopters as Soviet-made Iraqi Hinds. Critics say the disaster is in keeping with other incidents, such as the 1988 shooting down of a civilian Iranian airliner with the loss of all on board , by the USS Vincennes, which misidentified it as a bomber.
Those aboard the downed helicopters included members of a multinational field operation which had helped Iraqi Kurds to rebuild villages destroyed by battles with Iraqi troops after 1991 when the Gulf War ended.
General John Shalikashvili, the Chairman of the Joint Chiefs of Staff, said in July that there had been 'a shocking number of instances where individuals failed to do their jobs properly'.