Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (Type Certificate Previously Held by Rolls-Royce plc) Turbofan Engines

[Federal Register Volume 86, Number 64 (Tuesday, April 6, 2021)]
[Rules and Regulations]
[Pages 17710-17713]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-06952]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-1138; Project Identifier MCAI-2020-01258-E; 
Amendment 39-21488; AD 2021-07-11]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG 
(Type Certificate Previously Held by Rolls-Royce plc) Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Rolls-Royce Deutschland Ltd & Co KG (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. This AD was prompted by 
the manufacturer's analysis which determined that cracks may initiate 
in the front seal fins and cause cracks in the low-pressure turbine 
(LPT) disk. This AD requires repetitive inspection of the seal fins 
and, depending on the results of the inspection, replacement of the LPT 
disk before further flight. The FAA is issuing this AD to address the 
unsafe condition on these products.

DATES: This AD is effective May 11, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of May 11, 
2021.

ADDRESSES: For service information identified in this final rule, 
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. You may view this service information

[[Page 17711]]

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. It is 
also available at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2020-1138.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2020-1138; or in person at 
Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The AD docket contains this final rule, the 
mandatory continuing airworthiness information (MCAI), any comments 
received, and other information. The address for Docket Operations is 
U.S. Department of Transportation, Docket Operations, M-30, West 
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Kevin M. Clark, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7088; fax: (781) 238-7199; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain Rolls-Royce 
Deutschland Ltd & Co KG (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. The NPRM published in the Federal Register on 
December 21, 2020 (85 FR 82970). The NPRM was prompted by the 
manufacturer's analysis which determined that cracks may initiate in 
the front seal fins and cause cracks in the LPT disk. In the NPRM, the 
FAA proposed to require repetitive inspection of the seal fins and, 
depending on the results of the inspection, replacement of the LPT disk 
before further flight. 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 2020-0195, dated September 8, 2020 (referred to after 
this as ``the MCAI''), to address the unsafe condition on these 
products. The MCAI states:

    Analysis of certain LP turbine discs in service has 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 disc of the affected parts, as defined in this [EASA] AD.
    This condition, if not detected and corrected, could lead to 
crack propagation, possibly resulting in LP turbine disc failure and 
high-energy debris release, with consequent damage to, and reduced 
control of, the aeroplane.
    To address this potential unsafe condition, Rolls-Royce 
published the NMSB to provide inspection instructions.
    For the reason described above, this [EASA] AD requires 
repetitive ultra-high sensitivity fluorescent penetrant inspections 
of the seal fins of the affected parts and, depending on findings, 
replacement of affected parts.

    You may obtain further information by examining the MCAI in the AD 
docket at https://www.regulations.gov by searching for and locating 
Docket No. FAA-2020-1138.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from two commenters. The commenters were 
Boeing Commercial Airplanes (Boeing) and Rolls-Royce. Rolls-Royce 
requested a change that resulted in an update to this AD. Boeing 
supported the AD as written. The following presents the comments 
received on the NPRM and the FAA's response to each comment.

Request To Change Engine Shop Visit to Refurbishment Shop Visit

    Rolls-Royce requested that the FAA revise the references in 
paragraphs (g)(1) and (h)(1) of this AD from ``engine shop visit'' to 
``refurbishment shop visit.'' Rolls-Royce reasoned that the FAA 
introduced a different inspection frequency to that defined in Rolls-
Royce Non-Modification Service Bulletin (NMSB) Trent 1000 72-AK416, 
Initial Issue, dated June 29, 2020, and EASA AD 2020-0195, dated 
September 8, 2020. Rolls-Royce further reasoned that a pair of mating 
flanges may be separated at most engine shop visits even when 
undertaking specific hospital shop or check and repair workscopes. 
Rolls-Royce indicated that it was not their intent, nor is it required 
by the safety case presented to and agreed by EASA, to strip and 
inspect the LPT seals at hospital or check and repair shop visits.
    The FAA agrees. The FAA changed references in paragraphs (g)(1) and 
(h)(1) of this AD from ``engine shop visit'' to ``refurbishment shop 
visit.'' The FAA also updated paragraph (h)(1) of this AD to define a 
``refurbishment shop visit.''

Support for the AD

    Boeing expressed support for the AD as written.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety and the public interest 
require adopting this AD as proposed. Accordingly, the FAA is issuing 
this AD to address the unsafe condition on these products. Except for 
minor editorial changes and any other changes described previously, 
this AD is adopted as proposed in the NPRM. None of the changes will 
increase the economic burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Rolls-Royce NMSB Trent 1000 72-AK416, Initial 
Issue, dated June 29, 2020 (the NMSB). The NMSB provides instructions 
for inspecting the LPT stage 3 disk and the LPT stage 4 disk. This 
service information is reasonably available because the interested 
parties have access to it through their normal course of business or by 
the means identified in ADDRESSES.

Costs of Compliance

    The FAA estimates that this AD affects 26 engines installed on 
airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Inspect the LPT stage 3 disk and LPT    80 work-hours x $85 per               $0          $6,800        $176,800
 stage 4 disk.                           hour = $6,800.
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[[Page 17712]]

    The FAA estimates the following costs to do any necessary 
replacement that would be required based on the results of the required 
inspection. The agency has no way of determining the number of aircraft 
that might need this replacement:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace LPT stage 3 disk......................  0 work-hours x $85 per hour = $0        $336,158        $336,158
Replace LPT stage 4 disk......................  0 work-hours x $85 per hour = $0         406,345         406,345
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Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: General requirements. 
Under that section, Congress charges the FAA with promoting safe flight 
of civil aircraft in air commerce by prescribing regulations for 
practices, methods, and procedures the Administrator finds necessary 
for safety in air commerce. This regulation is within the scope of that 
authority because it addresses an unsafe condition that is likely to 
exist or develop on products identified in this rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2021-07-11 Rolls-Royce Deutschland Ltd & Co KG (Type Certificate 
previously held by Rolls-Royce plc): Amendment 39-21488; Docket No. 
FAA-2020-1138; Project Identifier MCAI-2020-01258-E.

(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)

[[Page 17713]]

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.

    Issued on March 23, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-06952 Filed 4-5-21; 8:45 am]
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