The Transportation Safety Board recommended in February 2011 that the Sikorsky S-92A helicopters be modified so that their gearboxes could run 30 minutes without oil. The recommendation was one of four made by the board after the crash of Cougar Flight 491 resulted in the deaths of 17 of 18 people on board in March 2009.
Lori Chynn, 47, of Deer Lake, N.L., lost her husband John Pelley, 41, a medic who was en route to a production platform, in the crash.
Transport Canada should have required Sikorsky to retrofit its aircraft to meet the 30-minute standard, she said in a recent interview.
"Any helicopter that flies over the Atlantic, which is a harsh environment, needs to be as safe as it can be. If that means the helicopters need a 30-minute run dry, then that's what they need," said Chynn.
"I won't be happy until the ... retrofit."
The safety board says in the crash of Flight 491, oil leaked out after a filter broke off and minutes later the helicopter plunged into the ocean.
The original recommendation from the board called for the requirement to be in place for all new versions of the Sikorsky helicopter and that it be phased in for existing machines.
Martin Eley, director general of civil aviation at Transport Canada, said the agency believes the intent of the run-dry recommendation has been achieved because of a modification to the helicopter to ensure oil won't leak out in the first place.
He said the original cause of the leak — a broken stud that held on the oil filter — has been addressed with new types of studs.
The helicopter was originally certified by a Federal Aviation Administration through a provision that said the chances of oil leaking out was "extremely remote," which was defined as a one in one million possibility.
Transportation Safety Board investigators concluded the "extremely remote" exception should simply be dropped, effectively requiring the company to come up with a method to make the gearbox capable of running 30 minutes after losing most of its oil.
However, Eley said taking out the "extremely remote" provision isn't necessary.
"We believe the work that's been done has very specifically addressed the circumstances of the Cougar accident. It would eliminate the possibility of that same failure happening," he said.
"Where we don't necessarily agree (with the safety board) is actually removing the words 'extremely remote,' " he said. "It's very difficult to do without a major change in the regulations."
He said the term is used elsewhere in the standards and is part of a wider regulatory philosophy.
Since the crash, he said, the guidelines for determining when the chance of failure is "extremely remote" have been tightened and improved.
Sikorsky spokesman Paul Jackson says numerous improvements have been made to the gearbox and other parts of the aircraft since the Cougar crash and it meets existing Federal Aviation Administration standards.
"Because of the transmission's robust design, regulators determined that the chance of a leak in the Sikorsky gearbox is extremely remote. Sikorsky continuously looks to develop and introduce safety enhancements, and has no higher priority," he wrote in an email.
Still, the safety board says on its website that its recommendation on the run-dry provision hasn't been fully satisfied.
"From the information received, it is not clear when and how the deficiencies identified ... will be addressed," says an update on its website posted last month.
A spokeswoman for Cougar helicopters in St. John's declined comment.
Chynn, who wrote to then transport minister Chuck Strahl in 2011 calling for action, said she will continue to advocate for the recommendation.
"Who holds Transport Canada accountable? I'll keep speaking out, but it's very difficult. I'm just a little lady who lives in Deer Lake," she said.
"But my husband needs a voice."