VANCOUVER — Transportation Safety Board investigators think they've zeroed in on the cause of a deadly helicopter crash in northwestern B.C. this week.
The pilot and three passengers heading to a mineral drill site died Wednesday morning when the Prism Helicopters Hughes 500 crashed upside down into the Kitsault River shortly after leaving Alice Arm, 150 kilometres northeast of Prince Rupert.
"We were able to determine that the aircraft came into the trees next to the river at a very steep angle," safety board spokesman Bill Yearwood said Friday. "On examination of the wreckage, its damage is consistent with the aircraft not being in control just before impact."
The probe turned up pre-impact damage to the controls that were not from a conventional mechanical failure, he said.
"We know there was a mechanical problem because of the loss of control but it was not a problem that's associated with ongoing maintenance or design," said Yearwood. "The aircraft was damaged by equipment that's not normally on the aircraft when it's in flight."
Yearwood said specific details would have to await the board's final report, which will likely not be published for several months.