Focus on Aegis Electronic System : Perplexing Questions Pose Stiff Test for Gulf Probe

The perplexing questions raised by the Pentagon’s sparse account of the Iranian airliner tragedy make clear that the Navy board of inquiry created Monday faces a major challenge in determining how the U.S. cruiser Vincennes could mistake a commercial passenger plane for a much smaller F-14 jet fighter.

American military experts questioned why, for example, the Vincennes’ ultra-sophisticated electronics system was unable to distinguish the civilian radar transmissions used by a commercial plane like the Iranian Airbus A-300 from the more powerful “target acquisition” radar used by military aircraft such as the F-14.

Questions also arose about the Navy’s assertion that the airliner was approaching the Vincennes at 450 knots or more than 500 miles an hour at an altitude of about 9,000 feet. Jane’s All the World’s Aircraft, an authoritative source, says the A-300 maximum speed below below 26,000 feet is 345 knots. The plane’s maximum cruising speed is listed as 484 knots, but only at 25,000 feet or greater, where air resistance is less.

A U.S. Air Force pilot familiar with the Airbus said the plane would have to have been in a steep dive to achieve 450 knots at that altitude. The Navy has given no indication the Airbus was in such a dive.

And some experts asked why Capt. Will C. Rogers III, the skipper of the Vincennes, struck with such devastating force at an aircraft he believed to be an F-14, which does not carry the air-to-ship missiles that pose a mortal threat to surface targets.

Much remains clouded by the speed and distance at which decisions were made. “It’s going to be difficult to answer any of these questions with certainty before the investigative team makes its report,” said Pentagon spokesman Fred Hoffman.

At the same time, a knowledgeable Pentagon source suggested that--to reduce the likelihood of another such accident--the United States may ask Saudi Arabia to extend its surveillance flights by airborne warning and control system (AWACS) planes. That “is certainly something that will be looked at in the coming weeks,” the source said.

An AWACS plane, unlike the Vincennes, experts said, could have seen the jetliner take off from Bandar Abbas and would have been able to determine by its rate of ascent whether it was military or civilian.

The United States has made no decision, however, to step up flights of its own Hawkeye aircraft, which have somewhat similar capabilities. Three or four Hawkeyes operate off the aircraft carrier Forrestal in the north Arabian Sea.

Experts emphasized in interviews Monday that they believe the Vincennes’ commander, faced with an unidentified plane flying directly at him at high speed during a naval fire fight, reacted responsibly in assuming his ship was in peril and shooting the plane down.

Incomprehensible Behavior

Also weighing in favor of Rogers’ decision--made during a seven-minute period as the plane was reportedly picked up on radar approaching the cruiser at high speed--was the incomprehensible behavior of the pilot of Iran Air Flight 655, say those knowledgeable in the technology and tactics of gulf naval forces.

As described by the Pentagon, the Iranian plane’s flight speed and altitude resembled those of past attackers, specialists said, and the Airbus did not respond to the Vincennes’ repeated warnings, broadcast over military and civilian channels, to identify itself or change course.

The flight’s profile “looked for all the world like an attack profile,” said RAND Corp. analyst Benjamin Lambeth, an expert on tactical air forces who flies both civilian and military aircraft.

“Here’s the Vincennes, she’s at general quarters, all buttoned up with a fight on her hands, and along comes this bogey,” Lambeth added, using the military aviator’s term for a target that is tracked from afar on radar.

Adm. William J. Crowe Jr., chairman of the Joint Chiefs of Staff, said Sunday that the doomed Iranian airliner took off from an airfield at Bandar Abbas, about 30 miles from where the Vincennes and another U.S. ship were battling several small Iranian gunboats.

Traveling at 450 knots, or more than 500 miles an hour, the jetliner approached to within nine miles of the Vincennes at an altitude of 9,000 feet, according to the navy.

Military experts said they were surprised that the crew of the Vincennes appeared to conclude with such certainty that the aircraft rising out Bandar Abbas, whose airfield serves both civilian and military planes, was an F-14.

As radar tenders aboard the Vincennes peered into their blinking screens at the approaching craft, said experts, they would have seen a single green blip that told little more than the plane’s airspeed and altitude.

But the Vincennes is also equipped with a highly advanced defense system known as Aegis, designed primarily to identify threatening planes at distances of hundreds of miles. Components of the Aegis combat system, including the SLQ, or “Slick-32” electronic surveillance system, should have allowed the Vincennes to listen to the electronic signals emitted from the craft approaching it.

The electronic surveillance system should have been able to distinguish between the high-powered electronic emissions that, say, an F-14’s airborne intercept radar or target attack radar should have been sending out and the much less powerful pulses of energy that would come from a civil airliner’s weather or navigation radar.

No Identification Capability

“We’ve been spending billions of dollars to build weapons that can attack from beyond visual range,” said Thomas S. Amlie, a radar expert and analyst in the Defense Department’s financial management office. “And yet, we have not succeeded in building the capability to distinguish between potentially hostile planes and those which are not.”

Even if the Vincennes believed it had positively identified the aircraft as an F-14 fighter, experts also question why Capt. Rogers launched two of the Navy’s Standard missiles without further indication that the plane had the ability to cause the ship substantial damage.

The U.S.-made F-14 aircraft, sold to Iran during the 1970s, was designed exclusively as a dogfighting aircraft, capable of engaging other aircraft but not designed to carry weapons that attack surface targets.

“Even to carry a dumb (unguided) bomb, the plane would have to be completely rewired,” said one source.

The Iranians’ American-made F-4 Phantom aircraft, however, carry weapons capable of causing substantial damage to the Vincennes, sources added, and Rogers may have been wary of concluding the craft was not an F-4.

A Difficult Task

“If he cannot tell the distinction between a civilian airliner and an F-14, his task of distinguishing between an F-14 and an F-4 would be that much more difficult,” said a Defense Department official who asked not to be identified.

Despite the remaining mysteries, military experts said they could understand why the Vincennes shot down the jetliner.

Lambeth and other experienced military pilots noted that, traveling at more than 500 miles per hour, Flight 655 would be traveling at a speed that civilian pilots ordinarily use only at much higher altitudes and on longer flights.

“He’d have to have the throttles back to the wall to be doing that speed,” said the high-ranking Defense Department official, who was once a naval aviator.

Most civilian pilots would avoid that kind of speed because at that altitude, the plane would gulp fuel, the official noted. Furthermore, pilots not flying over military test ranges or in international airspace are prohibited from flying faster than 250 knots when flying at altitudes below 10,000 feet.

‘Speed Is Life’

But “for a fighter pilot, speed is life,” said the Defense Department official, who called Flight 655’s unusual flight profile “consistent with a guy who had a guided weapon,” such as a Maverick missile, to deliver on the Vincennes.

While Rogers may have doubted that the Iranian air force has weapons capable of doing the job, this source added, “the captain is not going to bet his whole ship on what his intelligence tells them they have or don’t have, especially after the mistakes we’ve made on that count.”

That was a reference to the U.S. frigate Stark, which was struck by an Iraqi missile on May 17, 1987, killing 37 crewmen. Naval investigators found that Capt. Glenn Brindel had failed to react decisively to warnings that an Iraqi Mirage jet was flying toward his ship.