[Federal Register Volume 86, Number 154 (Friday, August 13, 2021)]
[Proposed Rules]
[Pages 44655-44657]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-17071]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0662; Project Identifier MCAI-2021-00031-E]
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: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Rolls-Royce Deutschland Ltd & Co KG (RRD) Trent 1000 model 
turbofan engines. This proposed AD was prompted by reports of high 
levels of wear on the seal fins on a small number of certain high-
pressure turbine triple seals. This proposed AD would require manual 
deactivation of the modulated air system (MAS) control valves. The FAA 
is proposing this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by September 
27, 2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: (202) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, 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. 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.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0662; 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 NPRM, the 
mandatory continuing airworthiness information (MCAI), any comments 
received, and other information. The street address for Docket 
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Kevin Clark, Aviation Safety Engineer, 
ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 
(781) 238-7088; fax: (781) 238-7199; email: kevin.m.clark@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2021-0662; Project Identifier 
MCAI-2021-00031-E'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. The FAA 
will consider all comments received by the closing date and may amend 
this proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
https://www.regulations.gov, including any personal information you 
provide. The agency will also post a report summarizing each 
substantive verbal contact received about this NPRM.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this NPRM, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and they will not be placed in the public 
docket of this NPRM. Submissions containing CBI should be sent to Kevin 
Clark, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803. Any commentary that the FAA receives which is not 
specifically designated as CBI will be placed in the public docket for 
this rulemaking.

Background

    The European Union Aviation Safety Agency (EASA), which is the 
Technical Agent for the Member States of the European Community, has 
issued EASA AD 2021-0009, dated January 8, 2021 (referred to after this 
as ``the MCAI''), to

[[Page 44656]]

address the unsafe condition on these products. The MCAI states:

    The Modulated Air System (MAS) optimises cooling air, extracted 
from the compressor, where full flow is not required at cruise 
conditions. It is only active during cruise. Recently, occurrences 
have been reported of finding high levels of wear on the seal fins 
on a small number of high pressure turbine triple seals, Part Number 
FW3448. The effect on the secondary air system was conservatively 
assessed due to the resultant increased turbine cooling air leakage, 
which changes the cooling flow around the intermediate pressure (IP) 
turbine disc.
    This condition, if not corrected, could lead to temperature 
increase at the IP turbine disc rim when the MAS is active, possibly 
resulting in IP 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 has issued the 
NMSB, providing instructions to manually 'lock-out' (deactivate) the 
MAS control valves.
    For the reason described above, this [EASA] AD requires to 
deactivate the MAS control valves. This [EASA] AD also specifies 
that the Master Minimum Equipment List (MMEL) item for `MAS 
inoperative', which has a limit of 120 days, does not apply when the 
system is manually deactivated.

    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-2021-0662.

FAA's Determination

    This product has been approved by EASA and is approved for 
operation in the United States. Pursuant to the FAA's bilateral 
agreement with the European Community, EASA has notified the FAA of the 
unsafe condition described in the MCAI and service information. The FAA 
is issuing this AD because the agency evaluated all the relevant 
information provided by EASA and has determined that the unsafe 
condition described previously is likely to exist or develop in other 
products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Rolls-Royce Alert Non-Modification Service 
Bulletin (NMSB) Trent 1000 75-AK642, Initial Issue, dated November 30, 
2020. This service information specifies procedures for deactivating 
the MAS control valves. 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.

Proposed AD Requirements in This NPRM

    This proposed AD would require manual deactivation of the MAS 
control valves. Manual deactivation of the MAS control valves changes 
the engine to an approved configuration that will produce engine 
indicating and crew alerting system (EICAS) status messages that do not 
indicate inoperative (failed) equipment. Consequently, when these 
messages are displayed, the operator's existing FAA-approved minimum 
equipment list (MEL) instructions and limitations, including the 120-
day operation limitation, do not apply.

Interim Action

    The FAA considers that this proposed AD would be an interim action. 
If final action is later identified, the FAA might consider additional 
rulemaking.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 4 engines installed on airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                    Cost per       Cost on U.S.
               Action                        Labor cost           Parts cost        product         operators
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Deactivate the MAS control valves...  2 work-hours x $85 per               $0             $170             $680
                                       hour = $170.
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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

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, and
    (3) Would 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 Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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:

Rolls-Royce Deutschland Ltd & Co KG (Type Certificate previously 
held by Rolls-Royce plc): Docket No. FAA-2021-0662; Project 
Identifier MCAI-2021-00031-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by September 27, 2021.

(b) Affected ADs

    None.

[[Page 44657]]

(c) Applicability

    This AD applies to Rolls-Royce Deutschland Ltd & Co KG (RRD) 
(Type Certificate previously held by Rolls-Royce plc) 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, and Trent 1000-R3 model 
turbofan engines.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of high levels of wear on the 
seal fins on a small number of certain high-pressure turbine (HPT) 
triple seals. The FAA is issuing this AD to prevent wear on the seal 
fins on the affected HPT triple seals. The unsafe condition, if not 
addressed, could result in failure of the intermediate-pressure 
turbine disk, loss of engine 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 the compliance time specified in figure 1 to paragraph 
(g) of this AD, deactivate the modulated air system (MAS) control 
valves using the Accomplishment Instructions, paragraphs 3.A.(6) and 
3.A.(7), of Rolls-Royce Alert Non-Modification Service Bulletin 
(NMSB) Trent 1000 75-AK642, Initial Issue, dated November 30, 2020.

    Note 1 to paragraph (g): Deactivation of the MAS control valves 
on an engine required by paragraph (g) of this AD changes the engine 
to an approved configuration that will produce engine indicating and 
crew alerting system (EICAS) status messages ``ENG MAS VALVE L/R'' 
and ``ENG MAS SYS TEST L/R.'' Since MAS is purposely disabled after 
compliance with paragraph (g) of this AD, these status messages do 
not indicate inoperative (failed) equipment and, consequently, the 
operator's existing FAA-approved minimum equipment list (MEL) 
instructions and limitations, including the 120-day operation 
limitation, do not apply.


    Note 2 to paragraph (g): Deactivation of the MAS control valves 
on an engine as required by paragraph (g) of this AD does not 
produce the EICAS status message ``ENG MAS VALVE SENSOR L/R.'' 
Consequently, when this EICAS message displays, it remains 
indicative of inoperative equipment, even if the MAS has been 
disabled as required by paragraph (g) of this AD. As a result, the 
corresponding MEL instructions and limitations apply whenever the 
EICAS status message ``ENG MAS VALVE SENSOR L/R'' is displayed.


               Figure 1 to Paragraph (g)--Compliance Time
------------------------------------------------------------------------
                                       Compliance time, whichever occurs
       MAS deactivation option         later after the effective date of
                                                this AD, A or B
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A....................................  Within 50 engine flight cycles
                                        (FCs) since new.
B....................................  Within 30 days or 100 FCs,
                                        whichever occurs first.
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(h) 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. Information may be emailed to: 
ANE-AD-AMOC@faa.gov.
    (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.

(i) 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: kevin.m.clark@faa.gov.
    (2) For 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. You 
may view this referenced 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.

    Issued on August 5, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-17071 Filed 8-12-21; 8:45 am]
BILLING CODE 4910-13-P


