A Cougar Helicopter Sikorsky S-92A. — Telegram file photo
HALIFAX — The U.S. aviation regulator says it won’t require the retrofit of a gearbox blamed in a fatal helicopter crash off Newfoundland because it would be too expensive for the industry.
The decision by the Federal Aviation Administration rejects a call by the Transportation Safety Board of Canada to phase-in a requirement that all Sikorsky S-92A gearboxes be capable of operating at least 30 minutes after losing oil.
The March 2009 crash of Cougar Flight 491 resulted in 17 deaths during a flight to an offshore oil platform, and has brought demands from the families of the victims that regulators in the United States, Canada and Europe change the rules governing the gearbox.
The FAA memo on the decision, obtained by The Canadian Press under U.S. freedom of information legislation, says the service record of the helicopter no longer supports the certification’s basic premise that the chances of an oil leak are “extremely remote.”
It also says a rule change for gearboxes will be proposed for future aircraft.
However, it says the helicopter has a good record and modifying the existing gearboxes would have a significant economic impact on the aviation industry and the cost would outweigh any improvements in safety.
The Transportation Safety Board found the primary cause of the crash in the North Atlantic was a massive loss of oil to the chopper’s main gearbox after two of three titanium studs snapped off the oil filter assembly during flight.