WASHINGTON — The Pentagon said Wednesday that the downing of two Army helicopters by U.S. fighters over Iraq last April was caused by a wide range of avoidable human error and it announced a sweeping overhaul of military flight procedures to prevent further accidents.
Calling the mishap "a tragedy that never should have happened," Defense Secretary William J. Perry approved recommendations that a general and another officer be relieved of their duties and told top commanders to decide whether others should face punitive action.
He also ordered a major shuffling of the operations of Air Force AWACS radar surveillance planes, which an investigative report Wednesday blamed as a major factor in the tragedy in which 26 people were killed.
The 21-volume report was the result of thousands of hours of analysis and interviews with more than 130 witnesses, including the pilots of the two F-15C fighters who fired the missiles that downed the two helicopters. It clearly stunned the Defense Department leadership.
Gen. John M. Shalikashvili, chairman of the Joint Chiefs of Staff, told reporters at a press conference that the investigation showed "there were a shocking number of instances in which individuals failed to do their jobs properly."
The general relieved of his duties was Air Force Brig. Gen. Jeffrey Scott Pilkington, who had been co-commander, along with a Turkish officer, of the U.S.-led operation to enforce the "no-fly" zone in northern Iraq.
Pentagon officials said that the "senior missions supervisor" for the AWACS operation also was relieved of his duties but they declined to disclose his name, pending further investigation. There was no indication whether he might be disciplined in the case.
Much of what was contained in Wednesday's report by a board of inquiry already had been disclosed, either in previous remarks by Pentagon officials or by the Los Angeles Times and other newspapers in recent weeks.
The document showed, for example, that the lead F-15C pilot mistook the two U.S. helicopters for Iraqi planes, and that his wingman, who was piloting the second fighter, did not try to prevent the shooting even though he could not confirm the identification.
The report also confirmed earlier speculation that the transponders carried by the two helicopters to identify them as American did not transmit the proper coded signals--though it said investigators have been unable to determine why the devices apparently malfunctioned.
But the investigators meted out the lion's share of the blame for the tragedy to the crew of the radar-surveillance plane, which it said failed to warn the F-15Cs and the Blackhawks of each other's presence, even though it had both sets of aircraft on its radar screens.
And it cited "a breakdown in command guidance and supervision" throughout the entire "no-fly" zone enforcement operation in northern Iraq, from a failure to integrate fighter and helicopter activities to a laxity in updating rules by which the F-15C fighters are permitted to attack an enemy.
The document said that the AWACS crew erroneously believed that it was not responsible for monitoring helicopter flights or for coordinating them with fighter operations and did not take a series of routine steps that could have prevented the tragedy.
And it said the mission crew commander of the AWACS squadron, who had flown only one sortie in the three previous months, "was not currently qualified in accordance with Air Force regulations."
Ominously, the report said that both the senior mission commander and the controller in charge of the area declined to testify on the advice of their lawyers, leaving investigators unable to tell whether they had activated a key warning device.
The report said that the investigators also were missing a four-minute segment of videotape from the AWACS plane, which was lost when a crew member recorded something else over it. But it said the slip appeared to be inadvertent and authorities were able to reconstruct the information.
Perry said Wednesday that the Pentagon already has changed flight procedures to help prevent such incidents in the future--including consolidating air-control for helicopter and fighter flights and tightening the conditions under which a U.S. jet can fire upon another plane.
But he also made clear that he had become very much displeased with the way the Air Force was operating its fleet of AWACS planes, which until now had been regarded as elite units.
He ordered a major overhaul of procedures and training for AWACS crews throughout the Air Force, particularly for joint operations involving the Air Force and other services. Such operations have become more common in combat situations.
And he directed the Pentagon's four-service "joint staff" to develop new guidelines for interservice operations that take account of lessons the military has learned from the April 14 incident.
The accident was the second tragedy this year in which errors by Air Force controllers were a critical factor. The other, a collision between an F-16D fighter and a C-130 transport over a North Carolina base in March, killed 23 and injured 100.
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The "no-fly" zone over northern Iraq was established by the United States and its allies just after the 1991 Persian Gulf War to prevent the forces of Iraqi President Saddam Hussein from raiding and killing Kurdish tribesmen who lived in that part of the country.