A Sikorsky S92 helicopter flown by Cougar Helicopters crashed Thursday morning while en route to the White Rose and Hibernia oil fields. (Cougar Helicopters)

Investigators found a broken mounting stud Friday in the wreckage of the helicopter that crashed off the coast of Newfoundland last week, a problem detected previously in Sikorsky helicopters.

The finding is being reviewed by the U.S. Federal Aviation Administration, which may issue a call to have the studs replaced on other Sikorsky helicopters.

"We are considering what action to take, but we certainly haven't issued anything yet, and I don't think we've determined when and exactly what we're going to issue," FAA spokeswoman Laura Brown told the Canadian Press from Washington.

Earlier Friday, the Transport Safety Board of Canada issued a press release saying the FAA was going to issue a directive demanding that all operators of Sikorsky S92-A helicopters worldwide immediately replace the studs on their choppers before flying them again.

(CBC)

"It's just a little bit ahead of where we are on this," Brown said. "They [TSB] made it sound like a fait accompli, and it's not yet."

TSB investigators discovered the broken mounting stud on the helicopter's main gearbox filter bowl when they started their examination of the crashed helicopter wreckage on Friday.

The transportation board immediately informed the FAA, along with Transport Canada and the National Transportation Safety Board.

The Sikorsky Aircraft Corporation had been aware of problems with its mounting studs. On Jan. 28, the U.S. manufacturer issued an alert saying that the titanium mounting studs should be replaced by steel studs on every helicopter within a year, or within 1,250 flight hours.

"We are continuing to assist with the investigation and are encouraged that progress is being made," Sikorsky spokesman Paul Jackson told CBC News in an email.

"We can't comment further on the investigation, because it remains ongoing. Our focus continues to be on ensuring that our operators are fully informed of any steps they should take as information becomes available."

Cause still under investigation

The cause of the crash is still under investigation, and whether the stud played a role hasn't been determined.

Mike Cunningham, a TSB investigator, told CBC News that the TSB flagged the broken bolt for other organizations on Friday as a precautionary measure.

"This stud could have been broken off during the impact or possibly during the recovery process," he said.

"It had been identified by the manufacturer as something that needed to be improved, so when we saw that it was broken, we took the steps necessary to let those guys know what was going on."

He said the stud is an important piece of equipment. If broken, it could cause a helicopter to lose oil pressure and eventually lose control.

17 dead, 1 survivor

On March 12, 17 people were killed when the Cougar Helicopters Sikorsky S92-A crashed into Atlantic Ocean, about 55 kilometres southeast of St. John's.

Preliminary investigations indicate the helicopter slammed into the water nose-first.

The helicopter was transporting crews to two of the three platforms working in the offshore oil industry.

Minutes before the crash, the crew had declared a mayday due to a main gearbox oil pressure problem. A log of the flight shows that the problem began when the helicopter was at a cruising altitude of 9,000 feet. The helicopter started a controlled descent, but appeared to have lost control at 800 feet. It went off the radar at 300 feet.

Most of the bodies recovered were still strapped in their seats from the fuselage, which was located on the bottom in 178 metres of water. The fuselage was pulled from the ocean and is now being stored at an airport hangar in St. John's.

One person survived the crash. Robert Decker, 27, who worked as an ice spotter, is recovering from severe injuries. He was still not well enough Friday to be interviewed by the RCMP about the crash.

With files from the Canadian Press