HALIFAX - Officials with Sikorsky and Cougar Helicopters are inspecting the main gearbox on an S-92 chopper to find out what caused a hairline crack on the critical component.
A spokesman for Cougar said Tuesday that a crew from Sikorsky is taking extra time examining the gearbox mounting feet, a day after the fracture was found on the helicopter when it returned from a training mission off Nova Scotia.
"Sikorsky wants to take a good, hard look at the actual gearbox so they're onsite to work with Cougar," Christian Kittleson said from the Victoria, B.C., headquarters for Cougar's parent company, VIH Aviation Group.
"They're working together to do the replacement of this gearbox and we expect it will be serviceable by Friday."
Cougar engineers were doing a standard inspection Monday when they discovered the crack on one of the mounting feet that attach the main gearbox to the airframe.
Kittleson said they have increased their examinations of the gearbox after two international aviation regulatory agencies recently issued airworthiness directives that mandate visual inspections of the mounting feet after every 10 hours of flight.
Cougar inspects the gearbox after every flight, Kittleson said.
Up until now, only companies that use the Sikorsky S-92 in the North Sea have found cracks on the mounting feet, according to the Federal Aviation Administration in the United States.
Paul Jackson, a spokesman with Sikorsky, said the company is working with Cougar to replace the defective gearbox.
"The hairline crack posed no immediate threat to safety," Jackson said in an email. "We are continuing to investigate the problem, and we remain completely confident in the inspection steps and remedy explained in our bulletin to all operators."
Sikorsky issued a bulletin to operators weeks ago notifying them of the need to increase inspections.
The S-92 is the same make of helicopter that was involved in a fatal crash off Newfoundland last March, although Kittleson said the cause of that crash was not linked to the same issue.
Investigators continue to probe the incident in March, but have said a mounting stud on the filter bowl assembly broke in flight, causing a loss of oil to the main gearbox.
In September, a Cougar helicopter made an emergency landing in Halifax after an onboard safety system indicated there were particles in the chopper's oil.
An official with the Newfoundland-based company said a chip indicator on the Sikorsky S-92 sensed there were loose fragments of material in the oil, which can cause problems in the main gearbox.