Transport Canada CF-2023-60

Requires inspection and replacement of certain bolts on the joint flange of the engine gas generator case and turbine support case. The AD stems from a report that, during a design review, P&WC identified that the existing low cycle fatigue (LCF) life of these flange bolts, at certain high-stress circumferential locations, is inadequate. Even though no fractured bolts have been reported to date in service, there is the potential that LCF cracks could develop on the flange bolt and lead to the bolt’s fracture. Multiple fractured bolts could lead to flange separation or case rupture, which may damage the engine and airplane.