AD 2020-20-07 Requires Initial And Repetitive Borescope Inspections (BSIS) Or Visual Inspections Of The IPC Shaft Assembly

The FAA is adopting a new airworthiness directive (AD) for all Rolls-Royce Deutschland Ltd & Co KG (RRD) Trent 1000-AE3, Trent 1000-CE3, Trent 1000-D3, Trent 1000-G3, Trent 1000-H3, Trent 1000-J3, Trent 1000-K3, Trent 1000-L3, Trent 1000-M3, Trent 1000-N3, Trent 1000-P3, Trent 1000-Q3, Trent 1000-R3, Trent 7000-72, and Trent 7000-72C model turbofan engines.

This AD was prompted by a report of crack findings in the front air seal on the intermediate-pressure compressor (IPC) shaft assembly during the stripping of a flight test engine. This AD requires initial and repetitive borescope inspections (BSIs) or visual inspections of the IPC shaft assembly and, depending on the results of the inspection, replacement of the IPC shaft assembly with a part eligible for installation. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective November 10, 2020.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to RRD Trent 1000-AE3, Trent 1000-CE3, Trent 1000-D3, Trent 1000-G3, Trent 1000-H3, Trent 1000-J3, Trent 1000-K3, Trent 1000-L3, Trent 1000-M3, Trent 1000-N3, Trent 1000-P3, Trent 1000-Q3, Trent 1000-R3, Trent 7000-72, and Trent 7000-72C model turbofan engines. The NPRM published in the Federal Register on April 2, 2020 (85 FR 18478). The NPRM was prompted by a report of crack findings in the front air seal on the IPC shaft assembly during the stripping of a flight test engine. The NPRM proposed to require initial and repetitive BSIs of the IPC shaft assembly and, depending on the results of the inspection, replacement of the IPC shaft assembly with a part eligible for installation. The FAA is issuing this AD to address the unsafe condition on these products.

The European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA AD 2019-0282, dated November 20, 2019 (referred to after this as “the MCAI”), to address the unsafe condition on these products.

The MCAI states:

• An occurrence was reported of finding cracks in the front air seal of the IPC shaft assembly during stripping of a flight test engine. Follow-up inspections of other in-shop engines revealed two more cracked front air seals of IPC shaft assemblies.
• This condition, if not detected and corrected, could lead to IPC shaft failure, possibly resulting in engine in-flight shut-down and consequent reduced control of the aeroplane.
• To address this potential unsafe condition, Rolls-Royce developed an inspection method and issued the NMSB, providing those inspection instructions.
• For the reason described above, this [EASA] AD requires repetitive on-wing inspections of the front air seal of the affected part at a specific area between the fourth (rearmost) seal fin of the IPC shaft assembly front air seal and the IPC Stage 1 disc and, depending on findings, removal from service of the engine for corrective action(s).

FMI: www.regulations.gov