A Sikorsky S92 helicopter flown by Cougar Helicopters crashed March 12 while en route to the White Rose and Hibernia oil fields. (Cougar Helicopters)

The company that owns the helicopter that crashed this month off Newfoundland says it is working on a plan to "resume helicopter operations" to the offshore oil platforms.

Seventeen people died when the Cougar Helicopters flight crashed on March 12 en route from St. John's to two offshore platforms. The lone survivor of the crash in the North Atlantic is recovering in hospital.

Cougar issued a news release Monday saying it is replacing the titanium studs on a filter assembly leading into the main gearbox on its remaining five S-92A Sikorsky helicopters.

The Transportation Safety Board informed Sikorsky Aircraft Corp. last week it had discovered two broken titanium mounting studs during its investigation of the downed chopper.

The safety board has also said it's not certain whether the discovery contributed to the crash, or if it occurred during the flight or upon impact with the ocean.

Cougar's news release doesn't describe any other planned changes to the helicopter, but the company says it is "working very closely with the offshore operators to devise a plan to resume helicopter operations." No target date is mentioned.

Studs subject to service bulletin

The titanium mounting studs were the subject of an "alert service bulletin" issued Jan. 28 by Sikorsky Aircraft Corp. of Stratford, Conn.

Robert Decker was the only passenger to survive a helicopter crash about 55 kilometres off Newfoundland's east coast. (Courtesy of Chris Jackman)

The bulletin said the gearbox filter bowl's titanium mounting studs should be replaced with steel mounting studs within 1,250 flight hours or within one year.

The Cougar news release issued Monday said the helicopter that crashed had flown 177 hours since the Jan. 28 service bulletin from Sikorsky.

It goes on to say "all aircraft manufacturers regularly issue alert service bulletins, with which operators comply under the scrutiny of regulators like Transport Canada and the U.S. Federal Aviation Authority."

The news release also says that Sikorsky had issued a revision Friday to its original service bulletin, requiring operators to replace the titanium studs "before flying the S-92s again."

Sikorsky later issued a statement Monday confirming that the majority of S-92 helicopters in service — 50 of 91 — have already had their mounting studs replaced.

"The company expects to have close to 100 per cent compliance by the end of this week," the statement said.

The company said it had contacted all S-92 helicopter operators March 20 after it learned of the broken titanium studs found on the Newfoundland-based chopper.

"While the investigation remains ongoing, our priority has been to maintain safety and eliminate any potential risks," said Marc Poland, vice-president of Sikorsky Global Helicopters.

66% of S-92s serve offshore oil customers

Approximately 66 per cent of current S-92 operators are offshore oil customers, the company said. The rest are performing search and rescue, airline and VIP missions.

The Maritime and Coast Guard Agency in Britain issued a statement Monday saying it had changed the studs and was once again flying its four Sikorskys from bases in Scotland.

Also, CHC Helicopter Corp. in New Richmond, B.C., said in an email that it had changed the studs over the weekend and the company had resumed flights of its S-92A.

The Federal Aviation Authority in the U.S. has said it expected to issue an order Monday calling for an immediate upgrade of the part on the aircraft in the United States.

However, by late in the afternoon the directive hadn't been posted on the agency's website.