Airworthiness Directives; Rolls-Royce plc (RR) RB211-Trent 800 Series Turbofan Engines

概要

We are revising an earlier proposed airworthiness directive (AD) for RR RB211-Trent 800 series turbofan engines. That NPRM proposed to revise the Trent 800 Time Limits Manual (TLM) of the Trent 800 engine maintenance manuals (EMMs). That NPRM was prompted by RR reducing the life limits of certain critical engine parts. This action revises that NPRM by proposing to supersede an existing AD to prohibit installation of one certain critical part and to increase the life of another critical part whose lives were previously reduced by that existing AD. We are proposing this supplemental NPRM to prevent the failure of critical rotating parts, which could result in uncontained failure of the engine and damage to the airplane. Because of the extensive changes since the NPRM was issued, we are reopening the comment period to allow the public the chance to comment on these proposed changes.