Summary
This notice revises an earlier proposed airworthiness directive (AD), applicable to (RR) RB211-535E4 series turbofan engines. That proposal would have required disassembling and inspecting all the engine mounts for cracks, refurbishing the engine mounts, and replacing the front mount thrust link spherical bearing. That proposal was prompted by reports of corrosion and fatigue cracks in the mount pins, the spherical bearings, and the support links and their respective spherical bearings. This action revises the proposed rule by expanding the applicability from RB211-535E4 series turbofan engines to include RB211-22B, RB211-524, and RB211-535 series turbofan engines, and by requiring the installation of a front engine mount housing and link support assembly that has a serialized, life limited spherical bearing installed. This action also revises the proposed rule by eliminating the requirements for disassembling and inspecting all the engine mounts for cracks, and refurbishing the engine mounts. The actions specified by this proposed AD are intended to prevent failure of the front engine mount housing and link support assembly due to cracks, that could result in loss of the engine.