Sikorsky orders worldwide inspections on S92 helicopters after incident in North Sea

Helicopter giant Sikorsky is requiring operators worldwide to do safety check inspections on all S92 aircraft, following an incident last month on an oil platform in the North Sea.

Sikorsky S92-A helicopters are used by Cougar Helicopters to service the Newfoundland offshore oil industry.

The directive from Sikorsky should have little effect on operations in the Newfoundland offshore, Cougar said, as six of eight aircraft owned by Cougar have already been inspected and cleared.

Flights to Nova Scotia offshore energy platforms were grounded briefly on Tuesday, while tests and inspections were ordered there.

Tail rotor issue

According to a BBC report, an S92 experienced a technical problem when coming in to land on the West Franklin platform in the U.K.'s North Sea on Dec. 28, which "gouged" the platform on the deck.

An official with Sikorsky said all S92 operators are being asked to conduct necessary inspections, including Cougar Helicopters in Newfoundland and Labrador.

Cougar confirmed with CBC that it conducted inspections on six S92s in the early morning hours Tuesday, and no anomalies were found. It expects to have the two remaining aircraft inspected by end of day.

In a statement, Sikorsky said an inspection is required before the next flight, with some leeway given for letting the helicopter return to base.

Inspections of the S92s are estimated to take 11 hours to complete, and that most operators should have their inspections completed by Wednesday, a spokesperson told CBC.

In March 2009, Cougar Flight 491 crashed off the coast of Newfoundland while en route to two offshore oil fields, killing 17 of the 18 people on board.

A 2011 Transportation Safety Board report indicated that the Sikorsky S92-A crashed 11 minutes into its flight, moments after one of the two pilots reported the helicopter's gearbox was losing oil pressure. 

Precautionary measure

According to Sikorsky, the decision was made by the company as a precautionary measure to ensure flight safety. 

"Safety is our top priority, and Sikorsky is working closely with our customer and investigative authorities to determine the root cause of the loss of tail rotor authority in the Dec. 28 installation landing," read a statement sent to CBC. 

"We are committed to keeping our customers informed. We will further communicate findings if the investigation reveals any safety or airworthiness issues that affect the S92 helicopter fleet."

While the investigation is ongoing and the root cause has yet to be confirmed, Cougar has confirmed that inspectors are focusing on the tail rotor pitch change shaft (TRPCS) bearing assembly.

The TRPCS was also the subject of an order issued on Dec. 9 by the United States Federal Aviation Administration. Authorities in the U.S. ordered that the part be removed or inspected on certain Sikorsky helicopters by Jan. 12.

Cougar said Sikorsky has previously released two alerts related to that part of the S92s and Cougar completed inspections well in advance of the compliance date with no faults found.