A Routine Beginning, and Then a Nightmare

PUERTO VALLARTA, Mexico â€”  To Antonio Alvarado, it looked perfect.

Monday was high tourist season on the sun-drenched Pacific coast, but his Alaska Airlines ground crews were moving like clockwork.

“Everything was beautiful,� he said.

It was busy: The airport had 40 planes in- and outbound. But Alaska had no over-bookings, no delays on its six U.S.-bound flights. As passengers began to board Flight 261, for San Francisco and Seattle, Alvarado called it a day.

Alicia Pena started checking in passengers at about 12:30 p.m. By 1 p.m., lines were forming behind all eight of the bright yellow Alaska counters.

“Some were very sad to be going home. Some wanted to stay--they loved Vallarta,� said Pena, a plump 30-year-old with blond curly hair, wearing the Alaska Airlines blue blazer. Most passengers looked like typical tourists, toting sombreros and wearing light summer clothes. A few carried jackets for use back in the rainy north.

One family sticks in Pena’s mind: the Clemetsons, a light-haired baby in a pink jumpsuit, traveling with her adoring parents and grandparents. Then there was the couple--Monte Donaldson and Colleen Whorley--who had been in the resort city planning their wedding.

“They were talking about the flowers for the wedding,� she recalled.

By 2 p.m., all 83 passengers had checked in. It was rush hour at the airport. The low-slung white building was pulsing with sunburned tourists clutching water bottles or backpacks.

Village Gets Many Visitors

Once a sleepy fishing village, Puerto Vallarta receives 1.1 million visitors a year. They travel on 29 different air carriers to and from Canada, the U.S. and Europe.

As the passengers relaxed over a last Corona or browsed the gift shops, airport personnel hustled to prepare their airplane.

The Alaska Airlines MD-83, a long-range version of the MD-80, had arrived in Puerto Vallarta less than half an hour before the passengers boarded. As usual for the flight, it had started the day in Anchorage, touched down in Seattle, then stopped again in San Francisco before heading to Mexico, said Alvarado.

Workers raced to clean and refuel the plane.

The catering company loaded the meals: chicken-with-shrimp trays for first-class, ham-and-Swiss hero sandwiches for tourist. The flight crew from the incoming flight was replaced by a new crew, fresh from 24 hours of rest.

At 1:32 p.m., the plane took off.

Flight 261 flew quickly and smoothly along the Pacific Route, the major north-south flyway on the West Coast. The aircraft shadowed the coast, almost entirely over land, through bright, clear skies, under the veteran command of Capt. Ted Thompson and First Officer William Tansky.

This middle portion of a normal, good-weather ride would be, one veteran MD-80 pilot said, a time to lean back, put your feet up.

“You climb . . . and you level off,� said Lou Aaronson, a retired Continental Airlines MD-80 pilot. “You usually have the autopilot on by then, so you sit back and enjoy the scenery. By then, the attendants are serving drinks, the passengers are settling in. It is absolutely routine.

“The pilot would probably follow the west coast of Mexico, then cut across Baja just south of the border. He probably picked up the regular jet route there. It pretty much follows the coast up to San Francisco.�

At 3:55, in the last routine moments of Flight 261, it was assigned a flight level of 31,000 feet and was cleared to San Francisco.

At 4:10, according to John Hammerschmidt of the National Transportation Safety Board, the pilot told a controller at the Los Angeles Center in Palmdale that he was “having control difficulties and had descended to 26,000 feet.�

A few seconds later the pilot reported that he was at 23,700 feet and “there was some discussion about their ability to control the aircraft.�

Responding to the controller’s request, the pilot asked for a block of airspace from 25,000 feet down to 20,000 and said the flight was “kind of stabilized and they were going to do some trouble-shooting,� Hammerschmidt said.

Four minutes later the Palmdale controller asked if they needed anything.

“The flight responded, ‘We’re still working,’ or something to that effect,� Hammerschmidt said.

At 4:15, after the flight was handed off to another controller’s sector, the crew members checked in, saying “they had a jammed stabilizer and were experiencing trouble maintaining altitude.� They asked if they could move the aircraft out over the water and descend in preparation for an emergency landing at Los Angeles International Airport.

A commercial airliner in mid-flight, a large object moving quickly through space, has few options for where it will move next--up, down or sideways. It has, however, an extraordinarily complex assembly of more than a million parts, an almost uncountable number of reasons for moving the way it does.

A jammed stabilizer is not a reason you want to experience.

The stabilizer is a horizontal plane, a kind of mini-wing, mounted on the MD-83 atop the tail. The stabilizer and the twin rear engines give the airplane its distinctive appearance.

The stabilizer is controlled by electric motors, which tilt it up or down to control the attitude--the up or down direction--of the airplane. It normally moves in very small increments.

“A horn sounds any time that stabilizer moves any more than one half a degree.� said Aaronson, the pilot. “You sure wouldn’t miss that.�

Problem Could Cause Quick Climb or Descent

Sources close to the investigation said they were looking at the possibility that 261 had what is called a “runaway stabilizer.� In that case, the stabilizer goes to either its full up or its full down position.

“If that happens, if it goes all the way, you could be in real trouble,� Aaronson said.

“If a trim ran away, the airplane would start to quickly climb or descend.�

Normally, a pilot would try to counter the stabilizer by pushing or pulling the yokes, the upright posts--essentially the steering wheels--directly in front of each pilot. The yokes are connected by cable to small tabs, called the elevators, on the back of the stabilizer and theoretically can override the stabilizer.

“The control pressure on the yokes would get very heavy. It can take the strength of both pilots to level a plane in those circumstances, even when you’re using your feet and your legs.�

Aaronson and other pilots said that if the pilots were unable to override a jammed stabilizer, either a steep climb or descent would result. In either case, the plane would eventually plummet out of control.

If the stabilizer was jammed full up, the aircraft would climb until it stalled. In the case of the MD-80, with its twin rear engines, an unresolved stall can cause the plane to dive tail first, or to spin wildly.

“If it’s in a spin or a high-speed spiral as it heads down, it would be awfully hard to recover,� Aaronson said.

At 4:17, Alaska Airlines Flight 261 was advised to proceed to 10,000 feet.

“That transmission,� Hammerschmidt said, “was not acknowledged.�

At 4:21, air traffic control lost radar contact.

Within minutes, witnesses on Anacapa Island saw Flight 261 plunge nose first into the sea.

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Sheridan reported from Puerto Vallarta and McDermott from Los Angeles.

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The Final Moments

Flight 261 followed the normal path for jetliners traveling between Puerto Vallarta, Mexico, and San Francisco, hugging the coastline until it passed over Los Angeles. When mechanical difficulties arose, reportedly with stabilizers in the tail section, the crew circled the MD-83 over the water and back toward LAX. A look at its last communications:

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Source:National Transportation Safety Board