ABC NEWS

Investigators are trying to determine the cause of a fighter jet crash caught on tape by spectators at an Iowa air show that killed a pilot.

Three jets in tight formation rumbled over the crowd at the Quad-City Air Show in Davenport, Iowa, Saturday when one of the pilots, 59-year-old Glenn Smith, appeared to lose control of his plane, a Soviet-era fighter plane.

A home video captured the pilots going into a complicated maneuver, switching places mid-air and passing within inches of each other before the plane made a dive straight down.

"We don't see anything mechanical at this time but we want to make sure that we have it documented that we have everything," said Asst. Chief Don Schaeffer of the Davenport Police Department.

Since 1991, air show accidents in North America have killed 72 pilots and performers, More than 12 million spectators attend air shows each year.

"There hasn't been a spectator fatality at a North American air show since 1952, and that's because of the strict rules that have been in place for nearly 60 years," said John Cudahy, president of International Council of Air Shows.

Aircraft must stay 500-1,500 feet away from crowds and avoid flying toward people, and aerobatic pilots must be tested regularly.

In the very different world of air racing, a P-51 Mustang slammed into the crowd last year and killed 11 in Reno, Nev.

Earlier this year, the National Transportation Safety Board called for stricter rules, more training for pilots and changes to the race course to better avoid spectators.

"They're going to see people flying airplanes right to the absolute edge of the envelope," said ABC News aviation consultant John Nance.

On Sunday, a squadron of planes flew over the crash site in the "missing man" formation before the air show continued. Randy Ball, a good friend of Smith's, told The Associated Press that the deceased pilot was a meticulous flier who would map every step of a flight plan beforehand.

Smith left a lucrative job at a Dallas-area technology firm for an early retirement of restoring Soviet fighter jets and flying to exhibitions across the country. Smith was also the newest member of the "Hoppers," according to the team's website. The Hoppers are a group of pilots who privately maintain and fly L-39 fighter jets at air shows and other exhibitions.

Smith began flying more than two decades ago and holds a commercial pilot's license, according to the website.

The Associated Press contributed to this report.