The war game ended abruptly when the Air Force RF-4C broke sharply to the left and dived threateningly toward the USS Saratoga. Hot on its tail, the pilot aboard the F-14 Tomcat, the Navy`s hottest warplane, sought advice from the aircraft carrier.

''Red and free on your contact,'' the Saratoga told him.

The phrase ''red and free'' stunned the pilot.

''Jesus!'' he exclaimed to his back seat radar officer. ''Do they want me to shoot this guy?''

''Yeah,'' the radarman said. ''Shoot!''

The pilot squeezed his trigger.

''I saw the Sidewinder dip low and to the inside of the turn,'' he said later. ''I saw it hit, probably around the stabilator on the port side, and then a big fireball.''

Moments later, two parachutes opened and safely deposited two bruised Air Force officers into the Mediterranean.

The downing of an unarmed Air Force RF-4C reconnaissance plane by the Navy F-14 last Sept. 22 highlights the vital role people still play in high-tech warfare-and how the possibility of human error can never be wrung from the equation.

An Air Force report of its investigation into the incident details how an apparently unrelated series of minor glitches and misunderstandings mushroomed into near disaster. The following reconstruction is drawn from that report, which included interviews with the fliers.

The Air Force plane left Aviano Air Base in Italy on a clear day at midafternoon, playing the role of an ''orange team'' intruder seeking to hunt down the Saratoga`s ''blue team'' battle group. Two F-14s had left the Saratoga eight minutes earlier with live missiles on their wings-contrary to an agreement with the Air Force that such weapons wouldn`t be used during war gaming.

Shortly after leaving the Saratoga, the F-14s were ordered by the ship`s combat controllers to track down a radar blip that proved to be an Illinois Air National Guard KC-135 tanker and an unmarked RF-4C Phantom it was refueling.

''I did not get close enough to see any discernible markings on the aircraft, but at that time assumed him to be friendly,'' Lt. Timothy Dorsey, piloting one of the F-14s, said of the Phantom.

''Hey Mike, there`s two F-14s that just joined up on our tanker,'' 1st Lt. Randy Sprouse, in the back seat of the Air Force Phantom, told Capt. Michael Ross, the pilot.

After taking on 5 tons of fuel, the reconnaissance plane began its final search for the Saratoga. Although Ross and Sprouse could no longer see any F- 14s, Dorsey`s jet doggedly stayed on the Phantom`s tail.

The RF-4C had to scrap its primary mission to hunt down the fleet electronically after its gear malfunctioned. Instead, its backup mission-already approved by the Navy-was to alert the Saratoga of its presence when it drew within 10 miles, and then fly within 1,000 feet of the carrier and read its hull number for a war game score.

But while the Air Force had alerted the Navy that the RF-4C might be in the neighborhood, the Navy hadn`t told its pilots.

Dorsey, 25, was the least experienced fighter pilot aboard the Saratoga, with only 245 hours in an F-14`s cockpit and only three months aboard a carrier. But Dorsey had another kind of experience: His father is Rear Adm. James Dorsey, a former naval aviator, commander of the carrier USS America and now an assistant deputy chief of naval operations.

Ross, aboard the Air Force plane, first spotted the Saratoga at 22 miles out. Dorsey reacted as the F-4 began its descent.

''Appears the Fox 4 may be inbound to mother,'' Dorsey told his ship`s combat controllers.

The shriek of the radar warning receiver was the first inkling Ross and Sprouse had that they again were being tailed by a Tomcat. No effort to communicate between planes was made.

''There`s a Navy F-14 sitting on our left wing at about 8 o`clock,''

Sprouse told Ross.

''Okay,'' Ross responded. ''He`s a good guy.''

But Dorsey didn`t feel that way about the Phantom.

''At 15 miles, the Phantom initiated a hard, nose-low left dive toward the carrier in what appeared to be an attack run,'' Dorsey said later.

''There he goes!'' Dorsey yelled at Lt. Cmdr. Edmund Holland, his radar intercept officer in the F-14`s back seat. The Tomcat`s crew, about 4,000 feet behind the Phantom, asked their ship what they should do.

''Red and free on your contact,'' the Saratoga radioed.

''Jesus!'' Dorsey exclaimed. ''Do they want me to shoot this guy?''

''Yes-shoot!'' Holland responded.

''Keep in mind,'' Dorsey said later of Holland, ''he`s thinking

`simulated` and `exercise` the entire time.''

But to Dorsey the call ''red and free'' was tantamount to an order to fire.

'' `Red and free` is clearance to fire, and when they`re telling me-as he`s making a strike on the boat-`Red and free on your contact,` I took it as clearance being pretty much an order,'' Dorsey said later. ''I was taught and told that `red and free` was an expression that would never be used unless it was a no-kidder, a real-world threat situation.''

Although Dorsey had never heard it used before outside a simulator, Navy pilots interviewed by the Air Force said the phrase is used routinely during air combat exercises off the Saratoga.

''As a fighter pilot, you`re trained to react decisively when called upon to do so,'' Dorsey said. ''In cases where you have hazard to your ship, if the ship`s in peril, or your wingman`s in peril, or you`re in peril, you need to react right away and you can`t stop and think about it . . .

''The combination of factors that I was seeing outside the airplane and hearing made me shoot,'' Dorsey said. ''It was very fast; I did not have time for a big three-party discussion.''

And Dorsey admitted he had forgotten that the Phantom had refueled from an Illinois Air National Guard tanker only minutes before.

''That did not enter my mind when I heard `red and free,` '' he said.

''Seeing the Phantom close in on the carrier, I armed up and squeezed the trigger.''

When the first missile failed to fire, Dorsey armed and fired a second Sidewinder.

''After the initial flash, a big fireball erupted on his left side,''

Dorsey recalled. ''My first indications of any problems with the sequence was a `What happened? What did you do? Did you shoot?` '' from his partner.

''I heard a `whish` sound from the right side of the aircraft, and I looked out and I said, `What was that?` '' Holland recalled later. ''I saw the front end of an F-4 and the back end was in flames-I said, `You shot him down!` and I was absolutely amazed.''

The Phantom`s crew was amazed, too. ''It was like a big huge flashbulb that went `Poof!''` Sprouse said later.

''The airplane just starts shaking like you wouldn`t believe,'' Ross said. ''I was up against the canopy.'' Both men thought they had collided with the F-14.