'How could this have happened?'

April 16, 1994|By Gilbert A. Lewthwaite | Gilbert A. Lewthwaite,Washington Bureau of The Sun

WASHINGTON -- The failure of two U.S. Black Hawk helicopters to respond to an electronic identity check by the U.S. F-15 pilots who shot them down Thursday over northern Iraq yesterday became the focus of the investigation into the "friendly fire" tragedy.

The helicopters' silence after the "friend or foe" inquiry from the U.S. fighters raises two possibilities: mechanical failure or operator error in either the fighters or the helicopters.

What appears clear, according to an initial report to Gen. John Shalikashvili, chairman of the Joint Chiefs of Staff, is that the lack of a "friendly" response from the helicopters reinforced the fighter pilots' mistaken visual identification of them as Iraqi Hind helicopters.

That led to the decision by the pilots to fire two missiles at the helicopters, killing all 26 crew members and passengers -- 15 of them Americans -- who were on a United Nations mission to protect Kurds from Iraqi persecution.

The rules of engagement for the F-15 flight, according to the general, did not require the pilots to give a warning of attack to the helicopters once they were identified as hostile.

The most baffling aspect of the mystery is that whatever went wrong was duplicated. Either equipment broke down in both helicopters or both fighters, or operator failures occurred simultaneously in two of the four cockpits. In addition, the planes could have contacted each other by radio.

"How could this have possibly happened?" a perplexed Defense Secretary William J. Perry said yesterday at a Pentagon news conference that left as many questions as it provided answers.

Mr. Perry said an Air Force-led investigation into the incident would uncover any personal culpability, systems failures or breaches of operating procedure.

"If individuals are found to be culpable, we will discipline them," he said. "If our procedures need changing, we will change them, and we will change them immediately."

One change in the allied mission to protect the Kurds in northern Iraq had already been ordered, he said, declining to give details. The United States also suspended air patrols over northern Iraq for one day to reinforce the safety procedures that failed Thursday.

The revelation that the F-15 pilots had used their IFF (Identify -- Friend or Foe) identification system on the helicopters before firing appeared to exonerate the pilots from one possible lapse in procedure.

But it left two crucial questions unanswered: How did they mistake the U.S. Black Hawks for Soviet-made Hinds in two visual fly-by checks? And what convinced the F-15 pilots that the helicopters were such a danger that they should be shot down immediately?

Implicit in the failure of the helicopters to give a "friendly" response to the fighters was the possibility that the transmitting equipment in the helicopters or the receiving equipment in the fighters was not working properly, or was not programmed properly. In the helicopters, the transmitters might simply not have been switched on.

Interviews with an F-15 pilot who flew on coordinated missions with helicopters during the Persian Gulf war, a Black Hawk pilot and another Army helicopter pilot produced this assessment of the possibilities:

* Mechanical failure: This presumes that the operators did everything correctly but that the communications link between the F-15s and the helicopters broke down. The flaw in this theory is that it would mean that equipment in both cockpits at either end of the link would have failed at the same time. The chances of that are regarded as remote.

* Operator error: This presumes that the equipment was working but was not properly used. It could have been miscoded. The codes are usually changed daily or by mission, and are entered into the "friend of foe" transmitting system by the pilot or the ground crew chief. The pilot is responsible for checking the code's accuracy.

The chances of two separate systems being miscoded are remote, according to the experts. Even if they were, this would be unlikely to provoke an attack, the F-15 pilot said, because the response would still be recognizable, even if incorrect.

Another possible error is that the manually activated IFF systems in the helicopters were turned off.

When a flight of aircraft -- either fixed-wing fighters or rotary-bladed helicopters -- takes off, the flight leader frequently orders only one of them to use its IFF system to minimize electronic interference.

That single plane would then check with ground radar control and the AWACS to make sure its identification signal was strong and clear. If it wasn't, another plane would be designated to switch its system on.

It is not known if this happened with the two helicopters Thursday.

Both helicopters pilots also might have turned off their IFF transmitters, because the transponders provide a radar "lock-on" the inquiring plane that can be used to target a radar-guided missile.

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