AD 2021-07-11

(a) Effective Date

    This airworthiness directive (AD) is effective May 11, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Rolls-Royce Deutschland Ltd & Co KG (Type 
Certificate previously held by Rolls-Royce plc) (RRD) Trent 1000-A2, 
1000-AE2, 1000-C2, 1000-CE2, 1000-D2, 1000-E2, 1000-G2, 1000-H2, 
1000-J2, 1000-K2, and 1000-L2 model turbofan engines with a low-
pressure turbine (LPT) stage 3 disk with part number (P/N) KH36323, 
or an LPT stage 4 disk with P/N KH33943, installed.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine 
Section.

(e) Unsafe Condition

    This AD was prompted by the manufacturer's analysis of certain 
LPT disks in service. The analysis determined that, due to rubbing 
contact with interstage static seals, cracks may initiate in the 
front seal fins, which could lead to cracks in the LPT stage 3 and 
stage 4 disks. The FAA is issuing this AD to prevent failure of the 
LPT disk. The unsafe condition, if not addressed, could result in 
uncontained LPT disk release, damage to the engine, and damage to 
the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    (1) During each refurbishment shop visit after the effective 
date of this AD, inspect the seal fins of the LPT stage 3 disk and 
the LPT stage 4 disk in accordance with the Accomplishment 
Instructions, paragraphs 3.B and 3.C, of Rolls-Royce Alert Non-
Modification Service Bulletin Trent 1000 72-AK416, Initial Issue, 
dated June 29, 2020.
    (i) For an engine that is in a refurbishment shop visit on the 
effective date of this AD, if the LPT stage 3 disk and LPT stage 4 
disk are exposed, perform the inspection before the engine is 
returned to service.
    (ii) [Reserved]
    (2) If, during any inspection required by paragraph (g)(1) of 
this AD, any crack is detected, before further flight, remove the 
affected LPT disk and replace it with a part eligible for 
installation.

(h) Definitions

    (1) For the purpose of this AD, a ``refurbishment shop visit'' 
is the induction of an engine into the shop for maintenance that 
involves removing the blades from a disk in the intermediate-
pressure turbine and replacing a disk in either the high-pressure 
compressor or high-pressure turbine.
    (2) For the purpose of this AD, a ``part eligible for 
installation'' is an LPT stage 3 disk or LPT stage 4 disk with zero 
flight cycles since new, or an LPT stage 3 disk or LPT stage 4 disk 
that has passed the inspection required by paragraph (g)(1) of this 
AD.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, ECO Branch, FAA, has the authority to approve 
AMOCs for this AD, if requested using the procedures found in 14 CFR 
39.19. In accordance with 14 CFR 39.19, send your request to your 
principal inspector or local Flight Standards District Office, as 
appropriate. If sending information directly to the manager of the 
certification office, send it to the attention of the person 
identified in Related Information. You may email your request to: 
[email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(j) Related Information

    (1) For more information about this AD, contact Kevin M. Clark, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781)

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238-7088; fax: (781) 238-7199; email: [email protected].
    (2) Refer to European Union Aviation Safety Agency (EASA) AD 
2020-0195, dated September 8, 2020, for more information. You may 
examine the EASA AD in the AD docket at https://www.regulations.gov 
by searching for and locating Docket No. FAA-2020-1138.

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Rolls-Royce Alert Non-Modification Service Bulletin Trent 
1000 72-AK416, Initial Issue, dated June 29, 2020.
    (ii) [Reserved]
    (3) For Rolls-Royce service information identified in this AD, 
contact Rolls-Royce plc, P.O. Box 31, Derby, DE24 8BJ, United 
Kingdom; phone: +44 (0)1332 242424; website: https://www.rolls-royce.com/contact-us.aspx.
    (4) You may view this service information at FAA, Airworthiness 
Products Section, Operational Safety Branch, 1200 District Avenue, 
Burlington, MA 01803. For information on the availability of this 
material at the FAA, call (781) 238-7759.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.