Chemical Reaction As the U.S. presses Libya over a nerve-gas plant, a shootout erupts. Did Gaddafi sacrifice two planes so Washington would take the heat?

By Ed Magnuson

The unlikely combination of Ronald Reagan and Muammar Gaddafi resembles nitroglycerin: it can produce an explosion at the slightest jolt. Last week, for the fourth time since 1981, just such a blowup took place in the Mediterranean skies off Tobruk, where a shootout that could have been taken right from the movie Top Gun ended in the downing of two Libyan jets by American pilots.

This time, however, there was a major difference. While the first three incidents occurred when Washington decided to swat the desert dictator, the latest confrontation was wholly unexpected. When the Libyan MiGs were destroyed after they persistently pursued two Navy F-14 fighters protecting the carrier U.S.S. John F. Kennedy, the U.S. found itself on the defensive not only militarily but also in its international relations.

. The eruption came as the Reagan Administration was applying calculated pressure on Gaddafi, and on U.S. allies, to prevent the production in Libya of poisonous gases that could be used in chemical warfare. The U.S. insists that a huge chemical plant at Rabta, 50 miles southwest of Tripoli and ringed with antiaircraft batteries, is primarily intended to produce mustard gas and chemical nerve agents. In a pre-Christmas TV interview, Reagan refused to rule out the possibility of a military strike against the plant. On background, Pentagon experts even suggested that Tomahawk cruise missiles, which can be launched by surface ships or submarines from as far as 800 miles away, might be used to level the suspect facility.

The clash that followed -- perhaps intended by Gaddafi -- threw the focus back on Washington's seeming eagerness to swing a big stick at easy targets. Soviet Foreign Minister Eduard Shevardnadze noted that the dogfight had "poisoned the atmosphere" as 142 nations opened a five-day conference in Paris over the weekend on ways to stop the increasing spread of chemical weapons. "Gaddafi must be pleased over the incident," said an Italian official last week. "It gives him a chance to play the victim."

It did little good for a presidential spokesman to protest that "we didn't try to pick a fight" or for senior U.S. officials to minimize the possibility that the U.S. would take out the weapons plant by force. Arab states lined up in the United Nations to denounce America's "brutal aggression." In the harshest language the Soviet Union has used toward the U.S. in two years, the Kremlin labeled the American action "state terrorism."

In Western Europe jittery American allies wondered whether Reagan was once again indulging himself by kicking his favorite terrorist -- and what the cost would be. Military bases went on alert in Italy, where Lampedusa Island was the target of an amateurish Libyan missile attack after the U.S. bombing of Tripoli in 1986. Britain supported the U.S. assertion that Rabta is intended for weapons production, but the Thatcher government urged Washington not to attack it. The French, who are host to the chemical-weapons conference at UNESCO headquarters, were irritated. The sharpest criticism came from the leftist Paris daily Liberation: "Gaddafi has lost two planes, but Reagan hasn't necessarily won out. These two were made to detest each other . . . One can understand that their farewells would be agonizing."

In its defense, the Pentagon released a dramatic videotape and voice recording of the aerial encounter taken from one of the F-14 Tomcats. The seven-minute audiotape chronicles the five evasive turns made by the Navy flyers in an effort to shake the MiG-23 "Floggers" that headed at them some 70 miles off the Libyan coast, well into international waters.

Moreover, the State Department disclosed that it has been quietly exchanging messages with Gaddafi for several weeks and that it sent the Libyan government a detailed explanation of last week's shooting incident. Still, Libya's U.N. Deputy Ambassador, Ali Sunni Muntasser, charged that the Navy had attacked two unarmed reconnaissance planes. U.S. Ambassador Vernon Walters responded by presenting the Security Council with blowups of two photos showing air-to-air missiles under the wings and fuselage of one of the Libyan MiGs. Charged Pentagon spokesman Dan Howard: "The Libyan Ambassador to the U.N. is a liar." At week's end Gaddafi proposed direct talks with the U.S. to resolve the dispute.

The Libyan Floggers had approached the American planes with apparent deliberation and determination. Flying at 20,000 ft., the F-14s picked up the Libyans on their radar screens at 11:57 a.m. on Wednesday. The "bogeys," as U.S. airmen call any potentially hostile planes, were 72 nautical miles away at 10,000 ft., heading directly toward the U.S. planes and the Kennedy.

The F-14s turned away from the approaching aircraft, a clear signal that the American pilots were not looking for a fight. To the surprise of the U.S. crews, the Libyan planes shifted abruptly ("jinked," in pilot jargon) to get back on a nose-to-nose lineup with the Americans. The distance between the two pairs of jets was closing at roughly 1,000 m.p.h.

In another evasive maneuver, the F-14s dove to 3,000 ft. This gave the Navy flyers a tactical advantage: their radar could now look up for a clear view of the approaching targets. The less sophisticated Soviet-made radars on the Libyan craft had to contend with the clutter of the sea.

At 11:59 the radar-intercept officer (RIO), seated behind the lead Tomcat pilot, armed his plane's short-range Sidewinder missiles and its longer-range Sparrow rockets. Outmanned and outgunned in their less maneuverable Floggers, the lone Libyan pilots had to fly their planes, watch their radars and handle their weapons without airborne help.

The U.S. pilots made three more efforts to shake their pursuers. Each . time, observers in a Navy E-2C radar plane flying nearby heard the Libyan ground controller order the MiG pilots to jink into potential collision courses with the Tomcats. The MiGs normally carry radar-guided Apex as well as heat-seeking Aphid missiles. While the Aphid homes in on a jet's fiery exhaust, the Apex is effective when launched at a target's nose.

At 12 noon the trailing Tomcat flying in the wing position locked its radar on one of the Floggers. In numerous past skirmishes, Libyan pilots had reported any such radar targeting to their ground controller, who had always told them to break off and head home. This time, U.S. authorities insisted, the pilot did not send any such alarm.

It was almost a minute after noon when the lead Tomcat pilot informed his flying mates, "Bogeys have jinked back at me again for the fifth time. They're on my nose now, inside of 20 miles." He could wait no longer. "Master arm on," he announced, taking the final step before delivering a Sparrow. At 14 miles separation, he barked, "Fox 1. Fox 1." He had triggered a Sparrow, called Fox 1 (a Sidewinder is Fox 2). The lead Tomcat launched another Sparrow at ten miles. Both missiles missed.

Instead of fleeing, the Floggers accelerated and continued their pursuit. They were now within six miles of the two F-14s. The Tomcat pilots then split their formation in a classic maneuver. As the two Floggers followed the U.S. wing plane, the lead Tomcat circled to get on the Libyan jets' tails.

The F-14 on the wing delivered a Sparrow, which hit one of the Libyan planes. "Good kill! Good kill!" shouted one of the Americans. The lead Tomcat closed on the remaining Flogger. At a mere 1.5 miles from the MiG -- a deadly distance in modern combat -- its RIO squeezed his Sidewinder trigger. The heat-seeking missile smashed into the Flogger. "Good kill!" cried a crewman. "Let's get out of here." The two Libyan pilots parachuted into the sea.

Why would Gaddafi provoke such a one-sided fight? "We're still scratching our heads," said the Pentagon's Howard. "It doesn't make sense." Yet Western standards of what does or does not make sense may bear little relation to the actions and motivations of Gaddafi, a man prone to mood swings and outlandish gestures. Gaddafi has become just about everybody's most despised dictator, but he holds a special place in Ronald Reagan's demonology. The President has repeatedly called Gaddafi a terrorist and a barbarian, and he proudly sports a T shirt that ridicules his No. 1 enemy with the legend KHADDAFY DUCK -- MAD DUCK OF THE MIDEAST.

The U.S. has a solid record of willingness to sock Libya. In 1981 the Navy shot down two Libyan jets whose pilots rashly fired at American planes over the Gulf of Sidra, which Gaddafi claims to be Libyan territory. Then, in March 1986, U.S. naval units deliberately steamed across what Gaddafi had called the "line of death," which marked the northern boundary of the gulf. When Libyan gunboats sailed out to challenge the Sixth Fleet, two were sunk, and a shore radar installation was destroyed. The following month, after a Libyan- backed terrorist bombed a disco in West Berlin, killing one American and injuring 60 others, U.S. F-111 and A-6 bombers attacked Tripoli and Benghazi and even struck at Gaddafi's headquarters in an apparent attempt to kill him.

Small wonder that Gaddafi -- and the rest of the world -- took the U.S. threats seriously. The Administration's hints of force were partly intended to bully other countries into withholding technical materials and personnel from the Rabta plant. "If we can scare the foreigners out, Gaddafi can't run the plant," said a U.S. intelligence source. Last September American diplomats warned their counterparts in West Germany, Italy, France, Britain and Japan that the U.S. had persuasive intelligence that the facility was intended to produce toxic chemicals on a massive scale. Nearby is a steelworks that can turn out the shells and casings needed to complete the poisonous weapons.

Although unwilling to divulge secret sources, U.S. officials confirmed that former workers in the plant had provided sensitive details. At first only the British Foreign Office seemed to be convinced of the danger. It conducted its own investigation of the complex and agreed with the U.S. findings. Later the French, Canadians and Egyptians advised the U.S. that they too were persuaded. But the Soviets and some U.S. allies claimed that the evidence was inconclusive.

Through newspaper leaks, the U.S. accused a West German firm, Imhausen- Chemie, of secretly supplying expertise and materials for building the plant. German officials insist that their investigation has turned up no proof to support these claims, though they agreed to examine more of the U.S. evidence this week. Privately the Reagan Administration warns that it may name five West German companies, two in Switzerland and some in unidentified other European nations that are involved in the Rabta project if their governments do not cut off such help to Gaddafi.

The announcement two weeks ago that the carrier Theodore Roosevelt had left Norfolk, Va., to join the Kennedy in the Mediterranean inspired fresh rumors of an impending U.S. attack on the Rabta plant. In that heated atmosphere, the Libyans could well have succumbed to nervousness and overreacted to the presence of the Kennedy off their coast.

Yet the Kennedy was sailing to the east last Wednesday. The carrier was near Crete, more than 600 miles away from the Rabta plant and 120 miles off recognized Libyan territorial waters, when the unexpected combat situation arose. Even the Libyans had to know that the F-14s were fighters on routine patrol, not bombers carrying out an attack.

Those facts lead to another, more complicated, theory about what happened: that Gaddafi deliberately sought the confrontation, sending his fighters on what amounted to a suicide mission in the hope of winning sympathy and provoking international criticism of the U.S. "Colonel Gaddafi knows that he is irrelevant within the Arab world and can win support only when he is perceived as the victim of superpower oppression," said Congressman Les Aspin, chairman of the House Armed Services Committee. "Two planes is a cheap price to pay so he can hear outpourings of fervent backing."

Was this reckless attack, then, really intended to fail? "We suspect -- mostly on the basis of the two Libyan pilots parachuting from their MiGs -- that they intentionally provoked the incident," said an Italian government official. Besides being concerned about the chemical plant, added a West German diplomat, Gaddafi "has been outraged by the P.L.O.'s concessions to the U.S. for direct contacts, and he could have seen a chance here to try to sabotage it."

The unpredictable nature of the Libyan attack and the trouble it has caused for the U.S. indicate that even after eight years of American pressure, Muammar Gaddafi retains his power to bedevil Washington. As Ronald Reagan departs from the White House, he leaves behind his Libyan nemesis as one more problem for George Bush to grapple with.

With reporting by Ricardo Chavira and Bruce van Voorst/Washington