Just before seven F14 Tomcats were launched from the USS Saratoga last Thursday night to chase down the Egyptian plane carrying the hijackers of the Achille Lauro, red-shirted ordnance sailors on the carrier's deck shined their flashlights on the noses of the fighters' Sidewinder missiles.

It was a check to determine whether the missiles were live and ready to fire. The heat of the flashlight beam was enough to send tones from the live missiles into the pilots' earphones, prompting the pilots to give a thumbs-up signal to the launching crew on the dark deck.

No F14 vaulted off the carrier without live missiles, Navy officials said. But these weapons were not meant for use against the Egyptian 737 airliner carrying the hijackers. Military officials feared instead that Libya might try to get even with the United States for downing two Libyan SU22 warplanes over the Gulf of Sidra in the summer of 1981, Navy sources said.

The F14 pilots had another weapon in mind for the 737, if the Egyptian pilot balked at following the Tomcats to Sigonella air base in Italy.

That was the Tomcats' fast-firing guns, which could have sent a bright stream of tracer bullets across the nose of the 737. But Pentagon sources said having to do so was considered unlikely.

Navy Secretary John F. Lehman Jr. said yesterday that the Navy flew a standard intercept against the Egyptian plane. This is a well-practiced maneuver requiring the precision of a ballet in the air to avoid what can be fatal missteps.

The F14 pilots were scheduled to describe the intercept at a news conference today at the U.S. Embassy in London, but Pentagon officials said it was canceled for fear of provoking terrorist action and the need to get the Saratoga back out to sea to resume NATO maneuvers.

However, the intercept was reconstructed through interviews with sources familiar with the operation. It followed the standard beginning at the outset, they said.

Saratoga Air Wing Commander Robert (Bubba) Brodsky, also nicknamed "Basketball Jones" because he carries a basketball off the carrier whenever it is in port and seeks pickup games, sent the standard intercept package of airplanes aloft, including E2C Hawkeye surveillance planes.

The first Hawkeye was launched off the Saratoga about 8:15 p.m. Egyptian time (2:15 p.m. EDT), two hours before the 737 took off. This allowed the plane to fly southward over the Adriatic Sea and focus its long-distance radar on the airport near Cairo when the Egyptian airliner took off. The Hawkeye, with radar that can see more than 200 miles, might have shown a streak of green on its scopes indicating the takeoff of the Egyptian 737. Navy officials would not confirm that the sighting came this early, although they said the Hawkeye has such a capability.

The seven F14 fighters, loaded with so much fuel and weaponry that they weighed about 30 tons, were launched from the carrier one after another. They were from two squadrons -- VF74, nicknamed The Bedevilers, and VF103, The Sluggers. One F14 pilot was Lt. Cdr. Steve Weatherspoon of VF74, pilot of the year for the Atlantic Fleet in 1974.

The planes, slung down the deck of the Saratoga by the carrier's catapult, went from zero to 130 mph in two seconds. That gave them enough lift to become airborne. From there the pilots climbed to about 20,000 feet to look for "a Texaco," a KA6D tanker plane that served as an aerial gas station for the operation.

During launch, the fighters had turned on their afterburners, which consume an immense amount of fuel. By the time the planes rose to 20,000 feet, they had to top off their tanks to stay aloft to intercept the 737.

That required each F14 pilot to "plug." This meant the pilot had to find an orbiting tanker, fly behind it at about 300 mph and line up the F14's probe with the tanker's basket.

The probe is a fuel pipe that sticks out of the front of the plane, while the basket is the connection at the end of the long hose trailing behind the tanker. The basket had lights around it, making it appear like the feathered end of a badminton shuttlecock. Spearing the basket with the probe requires precision flying by both F14 and tanker pilots; misses are common in the dark.

Once they refueled, the Tomcats flew southward to a rendezvous between the carrier and the expected course of the 737.

The aerial traffic cop in the E2C command and control plane told the fighter pilots what course to fly. But the pilots had other help that night. An Air Force "Burning Wind" C135 eavesdropping plane and a Navy A3 Whale were listening and waiting in ambush, too.

Sources said at least one of those planes carried Arabic-speaking crew members to monitor and talk with the Egyptian pilot of the 737 if he did not speak English, the international language for commercial aviation.

The F14 Tomcats flew figure-eights, trying to conserve fuel, while waiting for the E2C to tell them to move out for the intercept. The pilots had been briefed on how to surround the airliner once they found it.

The standard formation for four planes on such an intercept, sources said, is to put an F14 in front of the quarry, one on each wing and the fourth a mile or so behind to ride shotgun. The trailing fighter watches for interlopers or sudden hostile moves by the plane being forced down. With his sights fixed on the tail, or "the 6 o'oclock" position on the intercepted plane, the trailing fighter has the drop. His heat-seeking missiles would be able to go right for the quarry's tailpipe.

Although the E2C saw the green dot from the Egyptian 737, there were other dots on the radar console for the fighters to investigate. The F14 pilots, flying with no lights, sneaked close to several planes spotted by the E2C before they found the right tail number, which intelligence sources had learned.

Once the Egyptian airliner was identified and surrounded, an officer previously assigned to the intercept group to communicate with the airliner ordered the 737 pilot to follow the Tomcats to a landing in Sigonella.

If the Egyptian pilot had resisted, the F14s could have "thumped" him. This entails streaking across the path of the plane so it is bumped by the jet wash of the crossing fighter. There was no way the fighters could have touched the airliner, sources said, without risking a fiery midair collision. But neither tracer bullets nor thumping was needed to persuade the 737 to land at Sigonella. Pentagon sources said that if the Egytian pilot had refused to follow his escorting F14 fighters, the carrier pilots were under orders to take no further action until top authorities in Washington decided what to do next. Would President Reagan have ordered a shooting-down? A number of Navy officials said they doubted it. Said one Navy veteran of aerial intercepts: "It's just not in us to shoot down a commercial airliner."