500,000 Witness Deadly Crash : Aviation: The pilot of a Korean War-era jet, killed in a fireball on an El Toro runway in front of the air show crowd, is the third to die in eight years.

Before hundreds of thousands of stunned spectators, a Korean War-era jet fighter crashed in a tumbling fireball Sunday at the El Toro Air Show, instantly killing the pilot and scattering wreckage for almost a mile down the runway.

The restored F-86 Sabre, a mainstay of the U.S. Air Force in the early 1950s, went down about 1:45 p.m. during a solo aerobatic flight over the El Toro Marine Corps Air Station.

Witnesses said the vintage fighter crashed and exploded in the middle of a runway after the pilot could not pull out of a vertical loop about a quarter-mile from the viewing area. The impact spewed flaming debris along the ground parallel to the audience. No one on the ground was hurt.

“He went up in a big ol’ loop,” said Sebastian Murillo, 24, of Rowland Heights in Los Angeles County. “He came down, and I knew he was not going to make it. He was too low. We were running by then. It was like chaos. It was brutal.”

The civilian pilot, James A. Gregory, 40, of Amelia Island, Fla., was the third fatality at the popular El Toro Air Show in eight years. Gregory, a former Navy aviator, has a wife, Beth, and a 5-year-old daughter, Laura, friends said.

“It’s a great blow to me. He was my partner in the airplane and a great friend,” said Timothy J. Brown, of Fernandina, Fla., the co-owner of the F-86. “It’s one of those things you just don’t understand. He had flown the airplane 19 times in the last 16 days.”

The crowd, which was being warmed up for the featured attraction, the Air Force Thunderbirds, was shocked into silence. The show was halted for about 90 minutes.

The aircraft that crashed Sunday was an F-86 Mk 6, built for the Royal Canadian Air Force by Canadair Ltd. under license from North American aircraft company. About 1,800 of the Mark-6 version were made by the Canadian firm.

Brown and Gregory have flown the plane often at shows across the country. The aircraft was in excellent mechanical condition, Brown said, and Gregory was a skilled pilot very familiar with the Sabre.

“It was a sweetheart of an airplane,” he said. “It was one of the best jets ever built.”

Marine Corps and Federal Aviation Administration officials declined comment on the accident except to say that the cause is under investigation by the military and the National Transportation Safety Board.

Base spokeswoman Capt. Betsy Sweatt said she doubts the fatal crash will mean an end to the air shows. Officials will study the tragedy as the facts come in, she said, adding, “We review every show we do, whether there’s a fatality or not.”

No official explanation for the crash had been reached Sunday evening, but Brown and other air show pilots speculated that Gregory did not have enough height and speed to perform the loop. To successfully complete the maneuver, Brown said, an F-86 needs an altitude of 4,000 feet and to be going at least 136 m.p.h. at the top of the arc.

The F-86 was scheduled to perform in a mock dogfight with a Chinese-made MiG-15, another vintage aircraft that was one of the Sabre’s main adversaries during the Korean War.

But when Brown, who was going to fly the MiG on Sunday, became ill, Gregory decided to put on a single-plane aerobatic display instead. Immediately after the accident, spectators and some pilots speculated that Gregory may have been forced to improvise his routine rather than perform a prepared program.

Brown, however, said that he and Gregory have a planned series of maneuvers they use when they cannot stage the dogfight with the MiG, which is owned by a commercial pilot. He described the program as routine, “nothing out of the ordinary.”

The crash occurred on the second day of the 43rd annual El Toro Air Show, which attracted about a million spectators Saturday and Sunday for a wide array of aviation displays and aerial demonstrations.

Immediately after the thundering impact, spectators cried, hugged each other and comforted their children. In some cases, Marines on duty had to restrain part of the crowd that began to surge toward the flaming wreckage.

“When he came in that low to the ground, I knew something was going to happen,” said Marcia Cuneo of Mission Viejo, who had a front-row, VIP seat with her family. “I knew it was no stunt. It was just unbelievable.”

Even as visitors were still recoiling from the horrific event, military and civilian pilots resumed the air show about 3:15 p.m. “The feeling from the other fliers was that (the victim) was a professional pilot and he would have wanted the show to go on,” Capt. Sweatt said.

Air show pilots, who requested anonymity, said the Sabre pilot did not appear to have gained enough speed on the ascent to reach the correct altitude for the loop. They also said the maneuver was started 20 feet to 30 feet off the ground, which might have been too low.

When the crash occurred, Bret Willat, 41, a glider pilot from Warner Springs, had just landed his sailplane and was moving it off the runway a few dozen yards from the impact.

“I heard the explosion and just saw all those flames. It certainly did not look survivable,” Willat said. “You’ve got the top performers in the world flying here. So something like this is extremely rare.”

Within seconds of the impact, ambulance sirens blared and military and National Transportation Safety Board investigators were at the scene.

Many visitors, who had seen dozens of pyrotechnic displays during the morning, sensed immediately that the crash was no demonstration. Crowds surged forward to get a look and visitors quickly pulled out cameras and binoculars.

“It’s a horrible, horrible thing to see. You just never expect this,” said Tamara Bergum, of Fullerton, who burst into tears after the accident.

An incredulous Pam Hert, 27, of Huntington Beach, was sitting in the first row of the spectator area with her 6-year-old son and her father-in-law when the Sabre hit the runway in front of her.

“I looked at my father-in-law and asked, ‘Did we just see a crash?’ ” Hert said. “I wished it didn’t happen, and I did not want to believe it. My first thought was to pray for the pilot. I cried a bit.”

The black and yellow aircraft with “Sabre Dance” written on the side, along with two crossed swords, was the third plane to crash at the air show in the last eight years.

During the 1985 event, a civilian pilot and his passenger were killed when the World War II-vintage biplane they were flying smashed into an empty base chapel. In 1988, a Marine F/A-18 Hornet pancaked on a runway, seriously injuring the pilot.

In 1988, the Marine Corps temporarily reassessed whether to host the show after the crash of three Italian military jets into a crowd in West Germany. The military decided to go ahead with the El Toro event, noting that aircraft do not fly over spectator areas.

Times correspondent Anna Cekola contributed to this story.