WASHINGTON -- The Pentagon yesterday blamed a devastating series of human, procedural and technical errors for the "friendly fire" shoot-down of two U.S. Army helicopters by two U.S. Air Force F-15s in Iraq in April.
"It's a tragedy that never should have happened," Defense Secretary William J. Perry said at a Pentagon new conference, called to release the 21-volume report of the three-month investigation into the accident, which killed 26 people, including 15 military officers.
Shaken by the evidence of command and control breakdowns, inadequate training and poor performance, the Pentagon has ordered a review of its joint service operations, particularly those involving helicopters and fixed-wing planes.
"I have been particularly concerned that the problems leading to this incident may extend beyond the specific command and theater of operations involved," Mr. Perry said, adding that corrective action would be taken.
The report's findings will be sent to U.S. commanders in Europe to decide whether disciplinary or administrative proceedings should be taken against the plane crews involved. Possibilities range from court-martial to demotion in rank to reprimand.
"I pledge to you that we will take every action in our power to ensure full accountability and to ensure this type of accident is never again repeated," Mr. Perry said.
The downed helicopters were carrying U.S., British, French, Turkish and Kurdish officers of the United Nations military command. They were on an tour of villages in the northern Iraq "no-fly" zone when the F-15s fired two missiles at them, killing all aboard.
The errors that caused the shoot-down included:
* The failure of commanders to integrate the helicopter and fighter operations in the no-fly zone. As a result, neither set of U.S. pilots knew the others were flying there.
* The visual misidentification by the lead F-15 pilot of the two downed U.S. Black Hawk helicopters as Iraqi Hind helicopters and the failure of the second F-15 pilot, who did not identify the helicopters as Iraqi, to stop the attack.
* The use by the helicopter pilots of an incorrect code in the automatic friend-or-foe identification systems, which foiled attempts by the F-15 pilots to establish electronically that they were friendly.
* The failure of the crew of an advanced warning and control system (AWACS) plane to alert the F-15 pilots that the U.S. helicopters were in the area. The AWACS plane was commanded by an officer who was making his first flight in three months and who was "not current in his flying requirements."
"There were multiple causes of the shoot-down, any one of which, had it not existed, may have prevented the accident," said Air Force Maj. Gen. James Andrus, who headed the investigation.
After the accident, the rules of engagement for the U.N.'s Operation Provide Comfort were tightened for planes protecting Kurds from Iraqi air attack. Communications were simplified, and all aircraft in the no-fly zone were ordered to monitor a common radio frequency.
Gen. John M. Shalikashvili, the chairman of the Joint Chiefs of Staff, said he had ordered a review of procedures for operations involving both fixed-wing planes and helicopters, and improved training and performance evaluations of AWACS crews.
According to the investigation, this is what happened the morning of April 14, a day of clear skies and good visibility in Iraq:
At 7:36 a.m., the AWACS plane took off from Incirlik Air Force Base, Turkey, the first of 52 allied sorties scheduled to be flown that day. It was responsible for controlling and tracking flights in a 300-mile radius of northern Iraq.
The crew of the AWACS plane did not, according to the investigation, understand that the Black Hawk helicopters were part of the Operation Provide Comfort that they were monitoring. They did not routinely monitor U.N. helicopter flights or pass information about them to allied fighter pilots.
The two Black Hawk helicopters took off from their base at Diyarbakir, Turkey, at 8:22 a.m., headed for the U.N. military command center at Zakhu, Iraq. At 9:21, they reported their entry into the no-fly zone to the AWACS plane overhead.
Six minutes later, they landed at Zakhu to pick up the U.N. delegation. At 9.54 a.m., the helicopters reported to the AWACS plane their departure from Zakhu for the towns of Irbil and Salah ad Din.
In the meantime, at 9:35 a.m., the two F-15s had taken off from Incirlik to make a sweep of the no-fly zone to check for Iraqi planes. Operational rules required that the fighters check out the area before any other allied planes entered it. The F-15 pilots were unaware that the two Black Hawks were already there.
At 10:22, the lead F-15 pilot reported to the AWACS plane that he had radar contact with slow-moving, low-flying aircraft 52 miles inside the no-fly zone. The AWACS plane indicated it was unaware of any planes in the area. The F-15 pilots activated the friend-or-foe electronic check but failed to get the "friendly" response. On take-off from Diyarkabir, the helicopter pilots had programmed their identification systems with the code used for flights outside the no-fly zone.
Once inside the zone, they failed to change the entry. This foiled the F-15s' attempts to check their identity. A backup system failed to work, for reasons which the investigation failed to uncover.
The F-15s moved in to investigate. The AWACS plane confirmed it had made radar contact with the slow-flying helicopters. It gave no indication that they were "friendly," although the AWACS mission crew commander, senior weapons director and two controllers had access to electronic information that the U.S. helicopters were in the vicinity.
The lead F-15 pilot swept by the Black Hawks at 500 feet and 450 knots, identifying them as Iraqi Hinds. His wingman took a look, but could not identify them.
The pilots then positioned themselves five to 10 miles behind the helicopters and notified the AWACS plane that they had "engaged."
The F-15s fired their missiles at 10:30 and then passed over the crashed helicopters, still not realizing they were U.S. aircraft.