Transport Canada issues safety warning for some Bell helicopters after fatal crash west of Edmonton
Main rotor hub strap pin in some Bell models can shear off, detaching rotor, blade
A defective rotor pin suspected as the cause of a deadly helicopter crash west of Edmonton last week has grounded some models of Bell helicopters across North America.
The main rotor hub strap pins in certain Bell 212, 204B and 205 series helicopters must be inspected and replaced, Transport Canada said in an emergency airworthiness directive issued Monday.
The notice warns that the pins can fail, resulting in the rotor head and blade separating from the aircraft mid-flight.
About 200 helicopters across Canada may be affected by the directive.
"Failure of a main rotor hub strap pin will result in detachment of the main rotor blade and loss of control of the helicopter," the directive says.
Serial numbers on the rotor hub strap pins in the affected Bell helicopters must be checked against a list in the airworthiness directive before they can fly again, Transport Canada said.
"During investigation of a recent Bell 212 helicopter fatal accident in Canada, it has been discovered that one of the outboard main rotor hub strap pin[s] … sheared off during flight, leading to detachment of the main rotor blade and the main rotor head."
A spokesperson for the Transportation Safety Board of Canada told CBC News the Transport Canada notice was triggered by the TSB's investigation into the fatal June 28 crash of a Yellowhead Helicopters Ltd. Bell 212 near Evansburg, Alta.
Pilot Heath Coleman, 48, of Prince George, B.C., died as he worked to battle a wildfire.
Coleman was alone when the helicopter he was flying crashed in a rural area near the fire front.
The failed part had accumulated only 20 hours of service, the notice from Transport Canada said. It said an inspection of another Canadian Bell 212 found a main rotor hub strap pin "deformed" after about 29 hours in service.
The cause of the part failure has not been determined, Transport Canada said.
In a statement to CBC News, Transport Canada said 133 Bell 212 helicopters are registered in Canada.
In addition, there are 49 Canadian-registered Bell 205A1 and B, and 18 Canadian-registered Bell 204B helicopters that may be affected, the agency said.
Bell Helicopters issued a "removal of service advisory" on the defective parts late Monday.
The company said some of the main rotor hub strap pins "may not have been manufactured in accordance with the engineering design requirements."
Bell is requiring that records be checked before the next flight and that any defective parts be replaced. The company said the work on each aircraft could take 20 hours to complete.
A Bell spokesperson said company officials could not discuss details due to the ongoing crash investigation but offered condolences to the Coleman family.
If you lose the rotor blades, it's equivalent to an airplane losing its wings.-Jon Lee, TSB
Jon Lee, the TSB's manager of regional operations for Western Canada, said there were obvious signs at the crash site that the rotor pin had failed.
The rotor blades were not with the helicopter wreckage.
"To us as investigators, that's a very obvious first signal that something happened in-flight rather than as a result of hitting the ground," Lee said in an interview Tuesday.
One blade was found 23 metres from the crash site. The other was found on the second day of the investigation, 46 metres from the site.
"When we were able to recover the rotor blades, we were able to observe that this retention pin had sheared," Lee said.
The parts are being examined at the TSB lab.
'Gravity takes over'
Lee said the crash was not survivable.
"Essentially, with a helicopter, if you lose the rotor blades, it's equivalent to an airplane losing its wings," Lee said.
"You've lost all ability to maintain lift and gravity takes over."
The 175-hectare wildfire near Evansburg has been burning since June 22 when it triggered a temporary evacuation of nearby homes. It is now classified as under control.
'Something catastrophic happened'
Coleman was a longtime employee of Yellowhead Helicopters.
Company CEO Jacob Forman said Coleman was flying to pick up firefighters in a swamp near the fire.
Forman, who went to the scene, told CBC News his crew helped locate the second missing blade.
"It seemed like the critical piece of evidence," he said.
Forman said he never thought pilot error could be to blame. Coleman was a talented and deeply trusted member of his team for nearly a decade.
"Something catastrophic happened ... he didn't have a chance."