09/16/2011 08:29 EDT | Updated 11/16/2011 05:12 EST

Swissair lead investigator rejects crash theory

A lead investigator of the crash of Swissair Flight 111 near Peggys Cove, N.S., is rejecting the theory that an incendiary device might have been the cause of the fatal fire on board.

Larry Vance told The Canadian Press that if there was such a device, there would have been much more damage in the area in the cockpit where the fire started.

"Not only does that prove that we knew where the fire started — it was proof positive that there could not have been an incendiary device involved," he said from Ottawa on Friday.

"It would be like aiming a blow-torch at your head and burning only one hair."

Vance, who spent years with the Transportation Safety Board investigating the crash, said that he and his colleagues dismissed the possibility of an incendiary device after finding a single wire they concluded was the source of the fire.

In a Fifth Estate documentary, former Swissair investigator Tom Juby alleges there were sufficient grounds to suspect the crash may not have been an accident but that he was prevented by senior RCMP and aviation safety officials from pursuing his theory that an incendiary device might have been the cause of the fatal fire on board.

The flight from New York to Geneva crashed into the Atlantic Ocean on Sept. 2, 1998, killing 229 passengers and crew.

Juby, a retired RCMP sergeant, said high levels of magnesium — a key ingredient in an incendiary device — were discovered in the cockpit area. Several other investigators and a federal scientist who The Fifth Estate spoke to also supported Juby's informed suspicions.

But Vance said trace levels of magnesium found in the wiring and other wreckage could be easily explained by their prolonged exposure to sea water.

"Everybody knows that magnesium is in pretty high concentrations [in seawater], it makes up a large part of the salt in seawater," he said. "So I don't think anyone was particularly surprised to find that there was magnesium in minute amounts."