Operators of certain GE Aviation GEnx-1Bs that power Boeing 787s must replace fuel hydraulic lines at the next engine shop visit with re-designed components to eliminate the risk of leaks caused by flaws in the current parts, an FAA airworthiness directive set for publication Sept. 7 said.
The directive would come into force Oct. 12, meaning an affected engine put into the shop after that date would need the work, the FAA explained in the order.
GE’s probe of multiple fuel manifold links from 2018-2021 found that metal-to-metal joins were failing due to high-cycle fatigue (HCF) cracking.
“The manufacturer’s investigation revealed that variations in braze coverage and braze fillet radii caused high stress concentration factors at the braze block joints, leading to HCF failure in the tube bundles with brazed joints,” the FAA directive said.
The engine maker resigned multiple parts, eliminating the brazed joints. In February 2022, it issued a service bulletin explaining the issue and recommending operators swap out hydraulic lines during the next scheduled shop visit. The FAA directive is based on GE’s bulletin.
The AD affects engine serial numbers 956-102 through 958-775 as well as 958-795 and 958-802, the FAA said. About 280 affected engines are in the U.S. fleet.
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