Federal Aviation Administration November 7, 2011 – Federal Register Recent Federal Regulation Documents

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

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.

We propose to adopt a new airworthiness directive (AD) for PW4000 series turbofan engines. This proposed AD would require replacing the fuel metering unit (FMU), part number (P/N) 50U150, at the next shop visit after the effective date of this proposed AD. This proposed AD was prompted by an engine overspeed event that occurred during taxi and resulted in a high-pressure compressor (HPC) surge and tailpipe fire. We are proposing this AD to prevent engine overspeed on these engines, which could result in an uncontained engine failure and damage to the airplane.

We are superseding an existing airworthiness directive (AD) for the engines identified above. That AD currently requires initial and repetitive visual inspections of the forward engine mount assembly side links for cracks, stripping and reapplying the Sermetel W coating on the side links at every exposure of the side link. This new AD requires those same inspections, stripping and reapplying the Sermetel W coating, and adds two part numbers to the applicability. This AD was prompted by a review of the inspection program, which revealed that GE had omitted two affected side link part numbers from the applicability. We are issuing this AD to prevent failure of the side links and possible engine separation from the airplane.