AD 2020-14-04

(a) Effective Date

    This AD is effective July 23, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all Rolls-Royce Deutschland Ltd. & Co KG 
(RRD) (Type Certificate previously held by Rolls-Royce plc) Trent 
1000-A, Trent 1000-AE, Trent 1000-C, Trent 1000-CE, Trent 1000-D, 
Trent 1000-E, Trent 1000-G, and Trent 1000-H model turbofan engines.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7230, Turbine Engine 
Compressor Section.

(e) Unsafe Condition

    This AD was prompted by occurrences of in-service engine surges 
on affected RRD Trent model turbofan engines with a high number of 
intermediate pressure compressor (IPC) module flight hours since new 
or cycles since new. Investigation by the manufacturer shows reduced 
surge margin caused by IPC deterioration has led to in-service 
engine surges. The FAA is issuing this AD to reduce the risk of a 
dual-engine surge event. The unsafe condition, if not addressed, 
could result in failure of one or more engines, loss of thrust 
control, and loss of the airplane.

(f) Compliance

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

(g) Required Actions

    Within 30 days after the effective date of this AD, remove and 
replace one or both affected engines identified as ``Not Acceptable 
De-pair required'' in paragraph 3, Accomplishment Instructions, 
Table 2, ``Examples of compliant and non-compliant engine pairing 
combinations,'' of Rolls-Royce plc (RR) Alert Non-Modification 
Service Bulletin (NMSB) Trent 1000 72-AK468, Revision 1, dated March 
3, 2020.

(h) Installation Prohibition

    After the effective date of this AD, do not install on any 
aircraft, an engine pairing combination identified as ``Not 
Acceptable De-pair required'' in paragraph 3, Accomplishment 
Instructions, Table 2, ``Examples of compliant and non-compliant 
engine pairing combinations,'' of RR Alert NMSB Trent 1000 72-AK468, 
Revision 1, dated March 3, 2020.

(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 paragraph (j)(1) of this AD. 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 Stephen Elwin, 
Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: 781-238-7236; fax: 781-238-7199; email: 
[email protected].
    (2) Refer to European Union Aviation Safety Agency (EASA) AD 
2020-0010R2, dated March 4, 2020, for more information. You may 
examine the EASA AD in the AD docket on the internet at https://www.regulations.gov by searching for and locating it in Docket No. 
FAA-2020-0638.

(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 plc (RR) Alert Non-Modification Service Bulletin 
Trent 1000 72-AK468, Revision 1, dated March 3, 2020.
    (ii) [Reserved]
    (3) For RR service information identified in this AD, contact 
Rolls-Royce Deutschland Ltd & Co KG, Eschenweg 11, 15827 
Blankenfelde-Mahlow, Germany; phone: +49 (0) 33 708 6 0; email: 
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.