AD 2021-18-05

(a) Effective Date

    This airworthiness directive (AD) is effective October 21, 2021.

(b) Affected ADs

    This AD replaces AD 2020-15-12, Amendment 39-21175 (85 FR 45081, 
July 27, 2020).

(c) Applicability

    This AD applies to Rolls-Royce Deutschland Ltd & Co KG (Type 
Certificate previously held by Rolls-Royce plc) Trent 1000-A2, Trent 
1000-AE2, Trent 1000-C2, Trent 1000-CE2, Trent 1000-D2, Trent 1000-
E2, Trent 1000-G2, Trent 1000-H2, Trent 1000-J2, Trent 1000-K2, and 
Trent 1000-L2 model turbofan engines, except those that have the 
redesigned intermediate-pressure compressor (IPC) stage 1 and stage 
2 rotor blades introduced by Rolls-Royce (RR) Service Bulletin (SB) 
Trent 1000 72-J941, Initial Issue, dated December 6, 2016, or 
Revision 1, dated February 6, 2019.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by IPC rotor blade separations resulting in 
engine failures. The FAA is issuing this AD to prevent failure of 
the IPC. 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

    (1) After the effective date of this AD, before exceeding the 
initial inspection thresholds and repeat inspection intervals 
specified in Table 1 of RR Alert Non-Modification Service Bulletin 
(NMSB) Trent 1000 72-AK313, Revision 1, dated August 22, 2019 (RR 
NMSB Trent 1000 72-AK313 R1):
    (i) Perform initial ultrasonic inspections (USIs) of the IPC 
stage 1 rotor blade root (front face).
    (ii) Thereafter, perform repetitive USIs of the IPC stage 1 
rotor blade root (front face).
    (iii) Use the Accomplishment Instructions, paragraph 3.A.(1)(a) 
(on-wing) or 3.A.(2)(a) and (b) (in-shop), of RR NMSB Trent 1000 72-
AK313 R1 to perform the inspections.
    (2) After the effective date of this AD, before exceeding the 
initial inspection thresholds and repeat inspection intervals 
specified in Table 2 of RR NMSB Trent 1000 72-AK313 R1:
    (i) Perform initial visual inspections of the IPC stage 2 rotor 
blade root (front face) and IPC shaft stage 2 dovetail post (front 
face).
    (ii) Thereafter, perform repetitive visual inspections of the 
IPC stage 2 rotor blade root (front face) and IPC shaft stage 2 
dovetail post (front face).
    (iii) Use the Accomplishment Instructions, paragraph 3.B.(1)(a) 
(on-wing) or 3.B.(2)(b) (in-shop), of RR NMSB Trent 1000 72-AK313 R1 
to perform the inspections.
    (3) After the effective date of this AD, before exceeding the 
initial inspection threshold and repeat inspection intervals 
specified in Table 2 of RR NMSB Trent 1000 72-AK313 R1:
    (i) Perform initial USIs of IPC stage 2 rotor blade root (rear 
face).
    (ii) Thereafter, perform repetitive USIs of IPC stage 2 rotor 
blade root (rear face).
    (iii) Use the Accomplishment Instructions, paragraph 3.C.(1)(a) 
(on-wing) or 3.C.(2)(a) (in-shop), of RR NMSB Trent 1000 72-AK313 R1 
to perform the inspections.
    (4) After the effective date of this AD, within 5 engine flight 
cycles (FCs) after each occurrence in which any engine operates in 
asymmetric power conditions at an altitude of less than 28,000 feet, 
perform the following inspections on the engine not affected by the 
power reduction or in-flight shutdown (IFSD):
    (i) Perform initial USIs and visual inspections required by 
paragraphs (g)(1) through (3) of this AD.
    (ii) Thereafter, perform the repetitive USIs and visual 
inspections required by paragraphs (g)(1) through (3) of this AD.
    (iii) Use the service information and repetitive inspection 
thresholds required by paragraphs (g)(1)(iii), (2)(iii), and 
(3)(iii) to perform the inspections, as applicable.
    (5) After the effective date of this AD, within 5 engine FCs 
following a cabin depressurization event, perform the following 
inspections on both engines installed on the airplane:
    (i) Perform initial USIs and visual inspections required by 
paragraphs (g)(1) through (3) of this AD.
    (ii) Thereafter, perform the repetitive USIs and visual 
inspections required by paragraphs (g)(1) through (3) of this AD.
    (iii) Use the service information and repetitive inspection 
thresholds required by paragraphs (g)(1)(iii), (2)(iii), and 
(3)(iii) to perform the inspections, as applicable.
    (6) If any IPC stage 1 rotor blade root (front face), IPC stage 
2 rotor blade root (front face), or IPC stage 2 rotor blade root 
(rear face) is found cracked during any inspection required by this 
AD, replace the part with a part eligible for installation before 
further flight.
    (7) If any IPC shaft stage 2 dovetail post (front face) is found 
cracked during any inspection required by this AD, replace the IPC 
drum assembly.

(h) Mandatory Terminating Action

    At the next engine shop visit after the effective date of this 
AD, replace the IPC stage 1 and stage 2 rotor blades with redesigned 
IPC stage 1 and stage 2 rotor blades introduced by RR SB Trent 1000 
72-J941, Revision 1, dated February 6, 2019. Install the blades as 
kitted sets using the Accomplishment Instructions, paragraph 3.C. 
(In-Shop), of RR Alert SB Trent 1000 72-AK430, Initial Issue, dated 
August 17, 2020. This replacement of the IPC stage 1 and stage 2 
rotor blades as kitted sets is a terminating action for the initial 
and repetitive ultrasonic or visual inspection requirements, as 
applicable, required by paragraphs (g)(1) through (5) of this AD.

(i) Definitions

    (1) For the purpose of this AD, an ``asymmetric power 
condition'' is the operation of the airplane at an altitude of less 
than 28,000 feet, experiencing either single engine take-off, engine 
fault (reduced power on one engine), or single engine IFSD, which 
includes execution of any non-normal checklist procedure.
    (2) For the purpose of this AD, an ``engine shop visit'' is the 
induction of an engine into the shop for maintenance involving the 
separation of pairs of major mating engine case flanges, except that 
the separation of engine flanges solely for the purposes of 
transportation without subsequent engine maintenance does not 
constitute an engine shop visit.

(j) Credit for Previous Actions

    You may take credit for the initial inspections required by 
paragraphs (g)(1) through (5) of this AD if you performed these 
inspections before the effective date of this AD using any of the 
following.
    (1) RR Alert NMSB Trent 1000 72-AJ819, Revision 3, dated April 
13, 2018, or earlier revisions;
    (2) RR Alert NMSB Trent 1000 72-AJ814, Revision 4, dated 
September 28, 2018, or earlier revisions;
    (3) RR Alert NMSB Trent 1000 72-AK313, Initial Issue, dated May 
2, 2019; or
    (4) RR Alert NMSB Trent 1000 72-AK092, Revision 3, dated 
February 28, 2019, or earlier revisions.

(k) Special Flight Permit

    A special flight permit may be issued in accordance with 14 CFR 
21.197 and 21.199 to permit a one-time non-revenue ferry flight to a 
location where the engine can be removed from service for operators 
who are

[[Page 51604]]

prohibited from further flight due to a crack finding as a result of 
paragraph (g) of this AD. This ferry flight must be performed 
without passengers, involve non-ETOPS operation, and consume no more 
than three FCs.

(l) 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.

(m) Related Information

    (1) For more information about this AD, contact Kevin Clark, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781) 238-7088; fax: (781) 238-7199; 
email: [email protected].
    (2) Refer to European Union Aviation Safety Agency (EASA) AD 
2020-0240, dated November 5, 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-2021-0306.

(n) 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-AK313, Revision 1, dated August 22, 2019.
    (ii) Rolls-Royce Alert Service Bulletin Trent 1000 72-AK430, 
Initial Issue, dated August 17, 2020.
    (3) For Rolls-Royce service information identified in this AD, 
contact Rolls-Royce plc, Corporate Communications, P.O. Box 31, 
Derby, DE24 8BJ, United Kingdom; phone: +44 (0)1332 242424; fax: +44 
(0)1332 249936; website: https://www.rolls-royce.com/contact-us.aspx.
    (4) You may view this service information at the 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.