Tom Juby, who was an arson investigator, alleges the Transportation Safety Board didn't investigate that possibility even after high levels of magnesium -- a key ingredient in an incendiary device -- were discovered in the cockpit area.
"There was no opinion that there was such a device, it was merely a suspicion," Juby told The Canadian Press on Thursday from his home in New Minas, N.S.
"We didn't do a proper investigation. There was no criminal investigation done."
He said the basis of his suspicions hinged on unusually high levels of magnesium, iron oxide and zinc found in the cockpit area, and that testing at the time couldn't identify a natural source for the materials.
The flight from New York to Zurich crashed into the Atlantic Ocean off Peggy's Cove on Sept. 2, 1998, killing all 229 passengers and crew.
Juby said there were extensive tests done on about 28 short-circuited wires from the aircraft, but those tests were not complete.
"There was a very advanced test done that covered several areas and it produced more questions than it provided answers and we weren't allowed to continue to find those answers," he said.
Juby's allegations that he was prevented by senior RCMP and aviation safety officials from pursuing his theory the crash may have been caused by a criminal act are scheduled to be broadcast Friday in a report by CBC's "The Fifth Estate."
His assertion was criticized by Myron Ratnavale, who lost both parents and several friends on the flight.
"I just find it very, very far-fetched and I think it's an insult to the Canadian investigation team," he said from his home in Geneva.
"I have full faith in them and I don't believe a word of it."
A lengthy safety board investigation concluded the plane was brought down by a fire in the cockpit that was likely caused by sparking electrical wires.
In an email, Julie Leroux of the Transportation Safety Board said if there had been evidence of a criminal act in the crash of Swissair Flight 111, the RCMP would have taken over as lead investigator because the board cannot conduct criminal investigations.
Leroux says the board used a Natural Resources Canada laboratory to determine if arced wires recovered from the crash started the fire or were the result of the fire.
"During this analysis, the expert, Dr. Jim Brown, found magnesium and other elements on some of the wires. Dr. Brown concluded that the presence of a minor amount of magnesium was a result of long exposure to seawater," she says.
Leroux says no one from the board was available for an interview on Juby's allegations.
Sgt. Julie Gagnon said in an email statement that Juby's complaint was reviewed by the RCMP's office of its ethics adviser and the Mounties stand by the findings of that review, which it will not make public.
Transport Canada and Transportation Minister Denis Lebel's office did not return telephone calls seeking comment.
Juby couldn't explain how an incendiary device could have been placed on the plane, which was known as the "UN shuttle" because of the flight's popularity with United Nations staff.
He alleged that the Transportation Safety Board stuck with its finding that sparking electrical wires were to blame because it may have exposed itself to litigation after it recommended costly changes to material on planes to prevent similar accidents in the future.
"Look at the money that was spent by the airlines internationally as a result of that crash," he said.
The board's investigation of the crash cost $57 million and in its final report released in March 2003 it dismisses the possibility that the plane was brought down by a criminal act.
"The Royal Canadian Mounted Police found no evidence to support the involvement of any explosive or incendiary device, or other criminal act in the initiation of the in-flight fire," the report says.