DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0257; Project Identifier MCAI-2020-00712-E]
RIN 2120-AA64

Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG
(Type Certificate Previously Held by Rolls-Royce Deutschland GmbH,
Formerly BMW Rolls-Royce GmbH) 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 (type certificate
previously held by Rolls-Royce Deutschland GmbH, formerly BMW Rolls-
Royce GmbH) (RRD) BR700-710A2-20 model turbofan engines. This proposed
AD was prompted by flight data obtained from airplanes equipped with
certain Rockwell Collins avionics and auto-throttle systems that
demonstrated significant oscillation of the engine rotor revolution
speed during flight. This proposed AD would require initial and
repetitive recalculation of the consumed and remaining service life of
certain life-limited parts (LLPs). This proposed AD would also require
removal of an LLP prior to its approved life limit or within 90 days
after the effective date of this AD, whichever occurs later. 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 May 17, 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 Deutschland Ltd & Co KG, Eschenweg 11, Dahlewitz, 15827
Blankenfelde-Mahlow, Germany; phone: +49 (0) 33 7086-4040; 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-2021-0257; 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: Wego Wang, Aviation Safety Engineer,
ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone:
(781) 238-7134; fax: (781) 238-7199; email: Wego.Wang@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-2021-0257; Project Identifier
MCAI-2020-00712-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 FAA 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 final rule 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 final rule, 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 final rule. Submissions containing CBI
should be sent to Wego Wang, 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 2018-0268, dated December 11, 2018 and corrected on
February 20, 2019 (referred to after this as "the MCAI"), to address
the unsafe condition on these products. The MCAI states:

Flight data obtained from aeroplanes equipped with certain
Rockwell Collins avionics and auto-throttle system demonstrated
significant oscillation of the engine rotor revolution speed during
cruise. Analysis indicates that this affects the service life of the
affected LLP.

This condition, if not corrected, may lead to failure of an
affected LLP, possibly resulting in release of high-energy debris,
with consequent damage to, and/or reduced control of, the aeroplane.

To address this potentially unsafe condition, RRD issued the
NMSB, providing instructions to recalculate the consumed and
remaining service life of the affected LLP.

For the reasons described above, this [EASA] AD requires
repetitive recalculation of the service life (consumed and
remaining) of each affected LLP and, depending on the results,
replacement of each affected LLP before exceeding the life limit,
taking the re-calculated life consumption into account.

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-2021-0257.

FAA's Determination

This product has been approved by EASA and is approved for
operation in the United States. Pursuant to our bilateral agreement
with the European Community, EASA has notified us of the unsafe
condition described in the MCAI and service information referenced
above. The FAA is proposing this AD because the agency evaluated all
the relevant information provided by EASA and determined 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 RRD Alert Non-Modification Service Bulletin (NMSB)
SB-BR700-72-A900584, Revision 2, dated November 22, 2017 (the NMSB).
The NMSB describes procedures for amending flight cycle counting
requirements for affected LLPs on RRD BR700-710A2-20 model turbofan
engines. 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.

Other Related Service Information

The FAA reviewed Bombardier Service Bulletin (SB) 700-34-5021,
Revision 03, dated January 5, 2018, and Bombardier SB 700-34-6021,
Revision 03, dated January 5, 2018. These SBs describe procedures for
the implementation of the Global Vision Flight Deck Version 5 (V5)
software load on Bombardier Inc. Model BD-700-1A11 and BD-700-1A10
airplanes, respectively.

Proposed AD Requirements in This NPRM

This proposed AD would require repetitive recalculation of the
consumed and remaining service life of certain LLPs and replacement of
any LLP that has exceeded its approved life limit.

Differences Between This Proposed AD and the MCAI or Service Information

EASA AD 2018-0268 includes in its applicability engines installed
and operated on a pre-mod airplane during a period of 24 months prior
to the current installation. Instead of a period of 24 months, this AD
proposes to apply to engines installed and operated on a pre-mod
airplane at any time after January 1, 2017 to adjust for the additional
time since publication of the EASA AD.

In addition, EASA AD 2018-0268 requires an initial recalculation of
consumed and remaining service life of the low-pressure compressor
(LPC) disk at each engine removal for maintenance within 250 flight
cycles or 12 months, whichever occurs first after its effective date.
EASA AD 2018-0268 also requires recalculation of the consumed and
remaining life of the other affected LLPs after this period. This
proposed AD does not include the initial recalculation of the consumed
and remaining life of the LPC disk, but requires recalculation of
consumed and remaining service life of the disk and all other affected
LLPs within 90 days after the effective date of this proposed AD. The
FAA determined that the initial recalculation of the consumed and
remaining service life of the LPC disk, separately from the other LLPs,
is not needed to resolve the unsafe condition because the 12-month
initial inspection period in EASA AD 2018-0268 has passed.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 284 engines installed on airplanes of U.S. registry.

The FAA estimates the following costs to comply with this proposed AD:

Estimated Costs

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

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]

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