Gearbox crack found in Canadian Sikorsky helicopter

A problem with Sikorsky S-92A helicopters — one that had been believed to be limited to models used in the European offshore oil industry — has been found in a Halifax-based aircraft.

It’s the same type of helicopter that crashed into the ocean 55 kilometres southeast of St. John’s last winter, killing 17 of the 18 offshore oil industry workers aboard.

Cougar Helicopters Ltd., the company that operated the Sikorsky S-92A that crashed near Newfoundland and Labrador March 12, reported Monday that a crack has been found in a gearbox footing on one of the S-92As it operates in Halifax.

"During a scheduled inspection of the main gearbox feet of a S-92A Cougar, engineers identified a single hairline crack in the right-hand mounting foot of the main gearbox," a Cougar Helicopters news release said.

Four feet attach the main gearbox to the body of the helicopter. The gearbox drives the chopper's main rotor blades.

European Aviation Safety Agency (EASA) issued an emergency directive on Oct 24 saying cracks were found in parts of the Sikorsky S-92A that attach the main gearbox to the chopper's body.

Gearbox foot detached

In one case, a gearbox foot was completely detached from a chopper.

EASA says the problem could lead to loss of control of the helicopter.

A Cougar official says the safety of the passengers and flight crew aboard the Halifax chopper was not threatened by the cracked footing.

"We are not talking about a severing of the foot," said Cougar spokesman Christian Kittleson. "We are talking about just a crack to one of those mounting feet. So, we're very confident that the flight safety was never compromised in this case, and confident moving forward that it won't be compromised."

Until Monday, Sikorsky said the problem had only been found in helicopters working in the European offshore oil industry, which ferry workers to oil platforms in the North Sea.

After discovering the gearbox footing problems, Sikorsky and the U.S. Federal Aviation Agency ordered all S-92A operators to inspect gearbox feet after every 10 hours of flight.

"That scares the Dickens out of me.You know, it's just unheard of to have a part that has a 10-hour life limit. It makes me think they really don't know why the thing's failing," said John Eakin, a Texas-based pilot and engineer who works for a company called Air Data Research, which investigates aviation accidents.

"What assurance do they have that two of these mounts aren't going to fail within a 10-hour inspection period? What assurance can they give us it's not going to be a catastrophic failure next time they find one? I certainly wouldn't put my family on an aircraft that has to have a 10-hour inspection."

Cougar says it has been exceeding the directive to inspect gearbox footings every ten hours. Its officials say S-92A footings are now being inspected after every flight.

Customers notified

Cougar says it has notified all of its customers and is working with the manufacturer to try to determine what caused the crack.

The company says the helicopter was operated safely before the crack was found.

It says the main gearbox of the affected aircraft has been removed and will be replaced.

Following the crash of Cougar flight 491 last March, the Canada Newfoundland and Labrador Offshore Petroleum Board established an inquiry into offshore helicopter safety.

It is being led by Robert Wells, a retired Supreme Court judge.

Wells is hearing from witnesses this fall and coming winter.

The sole survivor of flight 491, Robert Decker, is scheduled to testify about his ordeal Thursday, Nov. 5. He has never spoken publicly about what happened on March 12.