In June 2014 , it was announced that the Canadian government had removed the mandatory requirement from Sikorsky to supply the CH-148 with a 30-minute run-dry main gearbox . This was a key safety feature defined as mandatory in the original RFQ and one of 7 concessions made to Sikorsky . The Canadian government states these concessions will not affect the safety of Armed Forces personnel . However , oil loss in the main gearbox followed by several other factors caused the 2009 crash of a S-92 , a civil version of the helicopter , off the coast of Newfoundland . Sikorsky has added an oil cooler bypass switch and states a similar accident is extremely unlikely . The effectiveness of the bypass switch has been questioned as it assumes that the leak will happen within the oil cooler assembly , and that the bypass can be activated in time to maintain enough oil . In the case of the S-92 crash , a titanium stud sheared causing catastrophic oil loss through the oil filter assembly
crash of a S-92
Cougar Helicopters Flight 91
Sikorsky CH-148 Cyclone