The Transportation Safety Board will open an investigation today into Sunday's air show disaster in Moose Jaw, Sask. that killed two U.S. stunt pilots.

Bobby Younkin and Jimmy Franklin were killed when the wings of their biplanes clipped one another before 20,000 horrified spectators, including family members.

Franklin's son, Kyle, was on the mike in the announcer's booth when the planes went down. Kyle performs with his father in a wing-walking show.

Franklin and Younkin were part of a civilian team of stunt pilots called the Masters of Disasters.

The team's third plane was able to make a safe landing. The pilot of that plane was Jim Leroy.

Two of the planes crossed past each other when the third came up from underneath and smashed into one of the planes.

There was a huge explosion of fire when the two planes collided, leaving a stunned silence in the crowd.

The air show was immediately cancelled. The Canadian military team, the Snowbirds, had been due to perform later in the afternoon to close the show.

The Masters of Disaster specialize in multi-plane dogfights and aggressive aerial acrobatics. Clive Tolley, executive director of the 2005 Saskatchewan Centennial 2005 Air Show, said the team is made up of veteran pilots.

"They have done this performance thousands of times safely," Tolley told CTV's Canada AM. "We don't know, at this point in time, what happened."

In December, Capt. Miles Selby of Delta, B.C. died in a crash involving two Snowbirds aerobatics team jets. Chuck Mallett of Edmonton suffered minor injuries -- he was able to open his parachute after being thrown from the plane in a fireball.

Despite suffering two crashes in less than a year, Tolley said he believes air shows are important in demonstrating the skill and professionalism of Canadian Forces pilots.

"I think if you get thrown off your horse, you get back on your horse. And my feeling would be that we continue the airshow business," Tolley said.

"It's a tremendous industry. It's good for our country. This is just an unfortunate accident."