MOOSE JAW, Sask. - A faulty seatbelt left unrepaired for several years and the failure of the pilot to ensure that he was strapped in properly led to the fatal crash of a Snowbird jet two years ago, says the final report on the May 2007 crash.

But the pilot's father is raising questions about whether the air force should have done more about the seatbelt problem that contributed to his son's death.

Capt. Shawn McCaughey's lap belt came undone while he was flying upside down during a practice flight prior to an air show in Montana, said the report released Monday.

McCaughey fell out of his seat and lost control of the plane, which plummeted to the ground.

The report says the seatbelt problem had been an issue for several years, but was never properly addressed.

The ground crew was not aware of a key part of the functional check used to ensure that the seatbelt was properly secured, said the report. This measure had been introduced after two incidents in 2002.

In one case, a seatbelt came unlatched during a training flight and the pilot was thrown from the seat, striking his helmet on the canopy. In this case, the pilot was able to roll the aircraft upright and recovered safely.

An investigation concluded that a long-term solution would be to redesign the key assembly of the seatbelt, but no modifications were ever made.

In an interview Monday, McCaughey's father, Ken, said he didn't believe his son was to blame for the fatal crash. He said his son had long voiced concerns about the seatbelt issue and followed the procedure he was shown to strap in properly.

"They should have fixed the problem prior to the crash so Shawn would have been alive again today," McCaughey told The Canadian Press from his home in Candiac, Que. "That's the very, very unfortunate part of it."

"They knew about the problem way back from 2002 and it took them five years and indecision from the part of the National Defence to fix the problem properly once and for all," he said.

"When the crash happened the problem was not solved. This is unbelievable and unacceptable."

Senior air force staff tried to explain at a news conference Monday why the seatbelt problem had never been fixed as prescribed.

"The problem as it was known and understood at the time was perceived as being under control with mitigating measures that were implemented," said Major-General Yvan Blondin. "There's nobody at that time that perceived the seriousness of the problem as much as we did afterwards."

Col. Gary Doiron, the director of flight safety, told the news conference the delay resulted in a gradual erosion of the sense of urgency to ensure this modification was put in place. "This was seen as just a technical change that will enhance safety of the lap belt, so the seriousness of the issue was lost."

Modifications were made after McCaughey's crash.

The report noted that McCaughey had problems with the seatbelt latch at least three times in the weeks before the crash, but each time the ground crew got the latch to close properly before he took off.

But these "false-locks" were never reported, according to 45-page report.

"During the many months spent training for the show season, (McCaughey's) assigned ground crewman reportedly reminded him several times to do his lap belt up carefully and to check for the click noise," said report.

The report said (McCaughey) would perform the check as requested, but then over time he would revert to "just doing the belt up quickly."

"The pilot did not complete the prescribed functional checks to ensure that the belt was locked properly prior to flight," said Doiron. "A combination of complacency and inadequate training played a role."

"Over time, a complacent attitude had been developed towards completion of the proper checks and there was an apparent knowledge gap among at least some of the aircrew regarding what the correct functional checks entailed," said Doiron.

The report also said McCaughey was under "significant stress" at the time and may not have been mentally prepared for the flight. The report cites the source of this stress was a combination of personal issues and his concern over the possibility of being grounded after being unable to complete a required manoeuvre in his jet.

However, the report also says that Snowbird team members indicated that McCaughey was able to fulfil his demanding flying role.