爱荷华州航空展 数千观众目睹坠机事故

That terrifying air show stunt turned into a disaster. A pilot killed and onlookers horrified. So what went wrong? ABC's John Muller is here with the details. John.

Bianna, it was a sicking feeling watching a 3-men formation suddenly become a 2-men formation a moment later the crash and the fireball. This morning we should learn the dead pilot's name. The investigation to what went wrong will take much longer. It all starts with that video tape, warning some of this may be hard to watch.

Three jets in tight formation rumble over the crowd at the Davenport Iowa Air Show. It's a beautiful sight but in a matter of seconds，it all goes horribly wrong, ending in a fiery crash right in front of the crowd of Labor Day Air Show spectators. This home video captured it all. The pilots are going to complicated maneuvers, switching places mid-air. But one of the pilots seems to lose control before he dives straight down. A massive fireball and then just smoke.

“He went nosed down into the ground and burst into flames. I was instantly in tears because I knew more likely that he didn't survive.”

In a nearby alfalfa field, the smoking wreckage of the Soviet L-39 jet used by a group of warplane enthusiast called the Hoppers. While the surviving Hoppers grieve the loss of one of their own, witnesses deal with the disturbing memories.

“It was very scary. It was very emotional. I mean I was actually filming it with my camera. And so it was surprising.”

So was there some type of mechanical failure involved? Well the investigation resumes today, the FAA collecting wreckage scattered all over that Iowa field.