Using fleetwide health and usage monitoring system data, Sikorsky has obtained FAA approval for a one-time life extension for specific S-92 main gearbox housings. The approval will help ease supply-chain constraints by allowing longer life for some gearboxes.
Fleet data was collected from more than 300 S-92s logging more than 2.3 million flight hours, allowing Sikorsky to develop a methodology “to more accurately determine the life limit for parts,” according to the company.
“The maximum earned life credit is 1,200 hours/3,600 ground-air-ground (GAG) cycles, representing an additional 12 to 18 months for an average S-92 offshore oil operator, and more than 24 months for others,” explained Leon Silva, v-p of Sikorsky's Global Commercial and Military Systems division. “Since it is offered as a one-time, end-of-life credit based upon individual usage, the final total hours of the serialized housings will differ, with the maximum possible being 5,500 hours.” The current life limit is 4,300 hours.
Sikorsky’s LifePlus methodology has been used before, with the first component life extension granted in 2023 for the S-92’s main rotor hub. In this case, the component’s life was revised to 15,000 hours from 9,000 hours or 45,000 GAG cycles. LifePlus “determines remaining component life of S-92 helicopter parts based on actual aircraft usage,” according to Sikorsky.