ITS NEARLY MIDNIGHT at the San Diego airport as the Delta Air Lines jet accelerates down the runway, bound for Los Angeles.

When it hits 126 knots, the plane unexpectedly noses up before the pilot pulls on the control column for takeoff. Speeding into the heavy clouds over the ocean, the nose pitches even higher. The amazed pilot desperately slams the control column forward as far as possible to try to force the nose back down.

This was the beginning of Delta Flight 1080 on April 12 last year. It was also the beginning of one of the most harrowing 55 minutes in recent aviation history. The story has a happy ending. After a series of potentially disastrous maneuvers, the plane landed safely as Los Angeles International Airport. Although the passengers had been told of a control problem, they never learned how close they had came to tragedy. Indeed, at least one of them was furious about being delayed.

The story of Flight 1080, as it turned out, illustrates how much airlines safety has improved in recent years. Tragic crashes still occur, like the one in San Diego last month that killed at least 150 people. But improvement in overall safety records is clearly shown by statistics of the National Transportation Safety Board.

According to the board's figures, the number of fatal accidents per million commercial aircraft miles flown ranged between .007 to .012 up until 1965. For the next decade, safer jets brought the range down to .003 to .005. During the last three years, it's come down even further to .001 to .002.

More reliable aircraft engines, backup control systems built into the newer planes and generally better air-traffic control are some of the major reasons for the improving records. Still, even the best of systems has its flaws and loop-holes, and in the end, passengers' lives often depend on the skill of the pilot up in the cockpit. The crash of two jumbo jets on the runway on Tenerife in the Canary Islands last year, killing 579, was blamed on a pilot in a KLM Royal Dutch Airlines plane who tried to take off without getting proper clearance. In the case of the San Diego crash, Pilots of the small private plane and the Pacific Southwest Airlines plane had been warned of each other's presence, but the two planes inexplicably collided anyway.

ON DELTA'S Flight 1080 leaving San Diego, the passengers were lucky enough to have Jack McMahan at the controls. A burly, affable 56-year-old, he is one of Delta's most experienced captains. During 36 years of flying, he has piloted biplanes, Grumman Wildcats (as a Marine Corps pilot during World War II) and over a dozen passenger planes, including all models of jumbo jets.

On Flight 1080, jack McMahan was piloting a Lockheed £1011 wide-body. Although the Lockheed plane carries up to 293 passengers, only 41 were on board the night. Eight stewardesses were aboard, and in the cockpit were Wilbur Radford, the copilot, and Steven Heidt, the engineer.

As Capt. McMahan shoved the control column forward in reponse to the too-steep climb, the plane's nose came down slightly and, at least momentarily, the plane seemed to return to a normal climb.

"After that," says Capt. McMahan, "the first thing I did was to check the setting for the stabilizer" (the two horizontal extensions on the tail, which control the plane's pitch). "According to our control panel," he says, "the stabilizer was set correctly." The captain retracted the landing gear, switched off the landing lights and turned off the "no smoking" signs in the passenger cabin.

At an altitude of 400 feet, however, the plane began nosing up again, and the pilot began to use "electric trim," another system for setting the stabilizer. That didn't work. He tried "manual trim." That didn't work either. "There just wasn't any response," he says. He tried both again, with no effect.

At 800 feet, with the plane climbing into thick clouds, the captain asked Steve Heidt, the engineer, to check the hydraulic system through which most of the controls work. "At this time," the captain adds, "I wasn't too upset, as the £1011 has four independent hydraulic systems - plenty of redundancy - and I was sure that one of several possible procedures would fix our problem."

Capt. McMahan unlatched and reset all switches associated with the plane's trim, or angle of flight. Will Radford, the copilot, checked control-panel warning lights to make sure they were working properly. Using control-panel devices, the engineer then double-checked the hydraulic systems. By 3,000 feet altitude, all emergency procedures concerning pitch and trim had been tried, and the crew couldn't find out what was wrong.

Air-traffic control was notified of the plane's plight by radio. Both the captain and the copilot got on the controls, exerting full forward force on the control column. Even so, as the plane climbed out over the Pacific Ocean, it pitched up more and more, far above the normal 15 degrees.

"I recall observing 3,000 feet . . . 3,500 feet . . . 4,500 feet on the altimeter," Capt McMahan says. "Pitch attitude exceeding 18 degrees . . . 20 degrees . . . 22 degrees. And the speed was decaying, 150 knots . . . 145 . . . 143 . . . 140."

In that sequence, the plane was fast running into the danger of a fatal stall, because with the nose up and the air speed dropping, the air wouldn't be moving across the wing fast enough to provide sufficient lift. The solution for that problem is to get the nose down and increase air speed - but the crew just couldn't get the nose down.

"Suddenly," Capt. McMahan says, "I had the horrifying realization that we were going to lose it. I'm trying to fly this thing as well as I can, and I thought, son of a bitch, I can't even fly it - it won't respond. I had a very clear mental picture of exactly what the aircraft was going to do - stall, roll to the left and descend vertically, disappearing into the clouds - at night - into the water." A week before, a Southern Airways DC9 had crashed, killing 68. And the week before that the Pan Am and the KLM planes had collided on Tenerife. "Accidents come in threes, they say, and I thought, 'My God, we're number three.'"

AT THAT INSTANT, the captain yanked all the throttles back, reducing power. For a pilot, it was an unnatural and illogical move. Reducing power would cut air speed further, and that would seem to increase risk of a stall. But, the captain says, "At the stage, you quit being methodical - you just do something and do it fast."

The tactic worked. "I felt a little change in control 'feel,' a little more control over the plane." The captain then advanced the No. 2 throttle, which increased the thrust of the No. 2 engine in the tail of the £1011. In the £1011, the two engines hanging on the wings of the plane, Nos. 1 and 3, are canted slightly downward, and their thrust makes the plane pitch up. But the No. 2 engine in the tail is canted slightly upward, and its thrust makes the plane pitch slightly downward. The increased thrust Capt. McMahan applied to the No. 2 engine did exactly that.

The nose slowly began to come down, to about 18 degrees; speed began picking up, to about 150 knots, and at 9,000 feet the plane broke out of the overcast and into bright moonlight. "A welcome change," the captain recalls. By adjusting the throttles slightly, the captain was able to stabilize the plane at about 10,000 feet.

Jane Hooper, the flight-attendant coordinator, had sensed something was wrong earlier and had been up to the cockpit. But she had been told to go back and "strap herself in," the engineer, Steve Heidt, says. "We were just too busy earlier," he recalls. Miss Hooper came back again. She was told there was a control problem, and she was asked to move all the passengers forward in the cabin to help get the nose down. "It probably didn't help much, but in that situation we figured every little bit would help," Heidt says.

Now, the question was, where to land. The captain immediately ruled out returning to cloud-covered San Diego. "No way was I going back into that weather." Palmdale Airport and Edwards Air Force Base were considered, but they close at 10 p.m., and it was after midnight. Phoenix and Las Vegas also were considered, but those choices would mean flying over the Sierra Nevada, where turbulence could be fatal to a plane already hard to control. That left Los Angeles International, and despite cloudy conditions there, too. Los Angeles was chosen.

Which direction should the plane come in from? At this point the cockpit voice recorder becomes available (earlier sections had been automatically erased as the 30-minute tape is continously reused) and the crew conversation indicates the captain was offered the option of flying over Los Angeles itself into the airport.

"That's no good," the captain said. ("I could imagine the holocuast if we went down over the city," he recalls later. "I figured if we lose it, we should lose it over water.")

So the Delta flight would come in from the ocean. That had some disadvantages pilots dislike landing over water at night, because there aren't any visual reference points. Among pilots, it's called landing "over a black hole." But that approach also held advantages: it made possible a long, straight-in approach. Pilots prefer that, at it gives them plenty of time to stabilize the plane and handle any control problems. And Jack McMahan was thoroughly familiar with that approach to Los Angeles International.

A normal touchdown, however, would be impossible. With no control over pitch so the pilot could force the nose down on the runway, the plane might float across the airport on a cushion of air and crash at the end. Even worse, as it neared touchdown, it might suddenly pitch up a couple of hundred feet, stall, then crash down into the runway. With no altitude to maneuver, there would be nothing the pilot could do.

The solution, Capt. McMahan figured, was to come in with flaps on the wings set at a reduced angle. That would allow the plane to come in at a higher speed - 170 knots instead of a normal 130 - which was risky itself, but it would allow the pilot to "bang" the plane down on the runway. "What we wanted was that positive ground contact," Copilot Radford says. The final seconds would be the key.

THE APPROACH descent began, and the Delta jet coasted down into the clouds hanging over Los Angeles. Crew members, meanwhile, were still trying to solve their problem. "You've got the stabilizer [indicator] showing full nose down . . . and you're not getting it . . . I can't believe it," Heidt, the engineer, said, according to the tape.

The copilot radioed to the Los Angeles tower to have fire trucks stand by. He also gave the number of passengers so that enough ambulances could be called.

Then, at 2,500 feet, the landing gear was extended, shifting the center of gravity, and the plane abruptly pitched up again. "I shoved the control column full forward," the captain says, "but we continued to climb while air speed deteriorated and we were going above the landing glide slope. My first thought was: 'Since we can't control the aircraft with the landing gear down, retract the gear, turn south and ditch in the ocean parallel to the coast.'"

Instead, the captain again boosted power on the No. 2 engine and cut thrust on No. 1 and No. 3. Slowly, slowly, the nose began dropping.

Copilot Radford: "1,000 feet - everything looking good - on glide path, on course."

At 500 feet, the Delta jet breaks out of the clouds, and the runway is dead ahead.

Capt. McMahan: "I'm gonna touch down and get on the brakes . . . right down the middle . . . and get it on . . . Help me hold the controls . . ."

The plane slams onto the runway at 170 knots, and as Capt. McMahan applies brakes, the copilot calls out the speed.

Copilot Radford: "130 . . . 120 . . . 110 . . . 100 . . . 90 . . . 80 . . . 70 knots, 60 knots, thank God."

Engineer Heidt: "Wheeee-eh."

Tower: "Well, Delta 1080, everything okay?"

Capt. McMahan: "Tell'em we're all right - we'll take it to the gate."

Jane Hooper rushed into the cockpit and kissed the pilot. "What was the problem?" she asked. Engineer Heidt answered, "We had up, but no down; we just kept going up, and up and up."

WHAT HAD GONE wrong? Within hours Lockheed and FAA engineers were swarming over the plane. The stabilizer has, on its trailing edges, small "elevators" that flip up and down in conjunction with the movement of the stabilizer, and the engineers quickly found the left elevator had stuck in the up position, causing the plane to pitch up. (There isn't any warning light in the £1011 cockpit to indicate a malfunctioning elevator, because the stabilizer is the main controlling device. In the dark night, there wasn't any way to see the jammed elevator, even if the problem had been suspected. Hence, there wasn't any way for the pilot to figure out what what was wrong.)

Why had it stuck? Water from rain, fog and mist had dripped down a structure in the tail onto a bearing. As the plane had repeatedly ascended and descended during the many flights, changes in pressure had sucked the water into the bearing. The bearing corroded and broke. When Capt. McMahan maneuvered his flight controls just before takeoff, the elevator, linked to the broken bearing, jammed.

Within hours, Lockheed had telephoned airlines all over the world using the £1011, warning them to check the bearing. (Several were found full of water and beginning to corrode.) Within days, the FAA issued an emergency airworthiness directive making the check mandatory in the United States. On June 5, 1977, even after making the check, a British Airways £1011 experienced a similar, though less severe, control problem. Taking off from Ailcante, Spain, the British plane, loaded with 160 passengers and headed for London, managed to divert to Barcelona and land safely. The FAA then ordered a visual check of the elevator before each £1011 takeoff. Lockheed has since devised a deflector to drain water away from the bearing, along with a seal on the bearing to keep water out and grease in, and it has rebuilt the bearing itself so that if any part fails, the other parts will function.

As for Delta's crew and passengers, they switched to another Delta plane and took off for Dallas, the next stop for Flight 1080. On the way to Dallas, Capt. McMahan got a note from a passenger saying, "All that screwing arounds in L.A. is going to make me late for a connection - what are you going to do about it?" The best he could, was the reply.

Late last year, Capt. McMahan won the FAA's prestigious Distinguished Service Award for bringing Flight 1080 in safely. Will Radford and Steve Heidt received FAA certificates of commendation.