ST. JOHN'S, NEWFOUNDLAND, CANADA — A faulty tail rotor was to blame for the helicopter crash off Canada's east coast earlier this year that killed 17 people, federal investigators said Thursday.
The Transportation Safety Board found severely damaged tail rotor driver gears led to the deadly March 12 crash.
"Without that tail rotor drive, your directional control ability is much more difficult," said lead investigator Mike Cunningham. "In other words, the nose is going up, then the nose is going down and it's rolling to the left and it's rolling to the right."
The tail rotor also helps keep the helicopter in the air, Cunningham said.
The Sikorsky S-92A helicopter, piloted by two crew members, crashed about 65 kilometers (40 miles) southeast of St. John's, Newfoundland, as it was carrying workers to two offshore oil platforms.
Investigators also found floatation devices failed to deploy when Cougar Flight 491 crashed, leaving the helicopter to sink into the ocean.
Earlier, officials had found two titanium mounting studs that attach to the main gearbox had cracked before the aircraft slammed into the ocean.
The loss of the studs would lead to a rapid loss of oil pressure and eventual loss of control of the helicopter, said agency officials.
Investigators are still trying to determine the origin of the cracks in the studs.
U.S. aviation officials have since ordered all titanium mounting studs on that model helicopter be replaced with steel as a result.
The families of 15 passengers who died in the crash and the one survivor, Robert Decker, are suing Sikorsky, Keystone Helicopters, and their parent company, United Technologies Corporation.
A public inquiry has also been launched to examine safety conditions for offshore oil workers.