Looking like a great gray whale, a U.S. Air Force C-141 Starlifter lumbered down out of a soft blue sky here shortly after dawn today, carrying in its belly 40 of the survivors of history's worst aircraft disaster.

There were no relatives on hand at Kelly Air Force Base, but dozens of reporters and cameramen and four representatives of Pan American World Airways watched as two survivors walked off the Air Force plane and 12 more were carried off on stretchers.

All the crash victims are suffering burns caused when their Pam Am 747 jumbo jet turned into a fireball after a KLM 747 struck it on the runway at Tenerife in the Canary Islands. The 14 who left the plane here was taken by ambulance bus to nearby Brooke Army Medical Center, home of one of the world's outstanding burn-treatment centers. Twenty-six other survivors were to fly to El Toro Marine Air Base, 40 miles east of Los Angeles.

At a hospital press conference, Edward L. Hess, who suffered only minor burns in the crash, told reporters that the 15-hour flight from the Canary Islands to San Antonio via McGuire Air Force Base in New Jersey "wasn't jolly by any stretch. There wasn't any joking." His hands shook violently as he spoke.

Hess was one of the lucky ones. The 39-year-old food broker from Phoenix, Ariz., walked away from the wreckage without even singeing his blue polo shirt, gray slacks or white shoes.

It wasn't until he returned to the wrecked to pull a woman free that he "got this," he said, point to a raw-looking burn on his forehead and minor burns on his hands.

Hess' wife, Mary, 36, was not so lucky. She was one of those admitted to the burn unit, where physicians said she and eight others are in serious condition, and three others are in very serious condition.

Those admitted suffer from burns covering between 15 and 70 per cent of their bodies, said Col. Basil A. Pruitt Jr., commander-in-chief of the U.S. Army Institute of Surgical Research, the burn unit's formal name.

Pruitt said the patients can expect at least one day in the hospital for every 1 per cent of their body that is burned. This means that seven of the patients will be hospitalized at least a month or more, and the most severely burned patients - who have less than a 50 per cent chance of surviving will be hospitalized for well over two months.

The injuries sustained by the patients are "very consistent" with those the unit has seen in other aircraft accident survivors, Pruitt said. The unit saw heavy use during the Vietnam war.

Pruitt said he does not know who would pay the patients' bills, but Hess said Pan Am had offered to pay for his wife's hospitalization. He also said the airline had not discussed with him its possible liability.

Hess said he had not seen the KLM plane bearing down on the Pan Am jet, adding that when the collision occurred his "personal thought was there was a bomb inside the plane."

"Within 30 seconds, the flames started and there were quite a few explosions, one after another," he said. Hess and his wife were in the first seats behind the cockpit, and all the passengers in the first-class cabin were trapped for a time by flames and the compartment's height off the ground.

"Then "the front collapsed and was completely engulfed . . . An explosion blew the flames away long enough for us to escape. It was very smoky and black, like plastic burning. I've been coughing up that smoke for two days," Hess said.

Hess said he had a very poor idea of the time sequence of the explosions and fires, estimating that he was in the plane for 10 to 15 minutes after the collision. In reality, if he had not gotten out much more quickly than that he would not have survived.

"It fees good to be alive," said Hess, "when you know you're dead and 10 minutes later you're still alive."

One of the passengers on the flight back, Isabelle Ford of Long Beach, Calif., died en route from "very extensive burns," said Dr. Scott McDougal, who flew with the survivors from McQuire to San Antonio.

Asked if she might have survived if she had been left in the hospital in the Canary Islands, McDougal called the possibility "very unlikely."

Physicians at Brooke Army Medical Center said that the Spanish physicians on the scene in the Canary Islands had provided "quite satisfactory care for the number of patients there were."

According to Pruitt the three major problems in treating burn patients are the high risk of infectioN, the need for as much as 2 1/2 times their normal caloric intake to prevent severe weight loss, and the need to keep up fluid levels.

Pruitt said that physicians had not yet had time to assess how badly each patient is burned, only what percentage of their bodies is burned.

Washington Post staff writer Bill Richards reported the following from Los Angeles:

The 26 crash victims flown to El Toro Marine Air Base were met at the airport by eight ambulances and 35 paramedic units.

Although several relatives were waiting at the airport - including a woman with a large bouquet of flowers - no one was allowed near the victims because of the risk of infectioN, doctors said.

Thirteen of the survivors were taken to a burn-treatment center at the University of California at Irvine. Private ambulances flew two to San Diego, two others were flown elsewhere on private planes and two who were not hurt were released. They left without speaking to the press.

Authorities at the medical center described the patients as "in good condition."

"We had one moderate injury that probably will take several weeks in the hospital," said an official, "and the rest we estimate will be here no more than a week."

Bonnie McCreary, whose parents were among those taken to the medical center, said her father "had just finished telling my mother how to get out" in case of an emergency when the two 747s collided on the ground.

Her father, Paul Heck, of Laguna Hills, Calif., "is afraid to fly . . . and always looks for the exits when he gets in a plane. It's the first hing he does," McCreary said.

She added that she had not learned that her mother had survived until Monday, when she heard it on the radio. Pan Am continued to list Mrs. Heck as dead until she told them otherwise, she said.