DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0259; Project Identifier AD-2020-01128-E]
RIN 2120-AA64

Airworthiness Directives; CFM International, S.A. Turbofan
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2013-26-01, which applies to all CFM International, S.A. (CFM) CFM56-3
and CFM56-7B model turbofan engines with a certain accessory gearbox
assembly (AGB) not equipped with a handcranking pad oil dynamic seal
assembly. AD 2013-26-01 requires an independent inspection to verify
re-installation of the handcranking pad cover after removal of the pad
cover for maintenance. Since the FAA issued AD 2013-26-01, a dual-
engine oil loss event occurred, prompting CFM to revise its service
information to provide procedures for reworking and reidentifying the
AGB. The FAA has also evaluated the requirement to install a redesigned
handcranking pad oil dynamic seal assembly in response to the dual-
engine oil loss event. This proposed AD would continue to require
independent inspection to verify re-installation of the AGB
handcranking pad cover after maintenance. This proposed AD would
require the replacement of the affected AGB as a terminating action to
the inspection requirement. 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 June 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 CFM
International, S.A., Aviation Operations Center, 1 Neumann Way, M/D
Room 285, Cincinnati, OH 45125; phone: (877) 432-3272; email:
fleetsupport@ge.com. 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-2021-0259; 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, any comments
received, and other information. The street address for Docket
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Christopher McGuire, Aviation Safety
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803;
phone: (781) 238-7120; fax: (781) 238-7199; email:
Chris.McGuire@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under ADDRESSES. Include "Docket No. FAA-2021-0259; Project
Identifier AD-2020-01128-E" at the beginning of your comments. The
most helpful comments reference a specific portion of the final rule,
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 NPRM 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
Christopher McGuire, 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 FAA issued AD 2013-26-01, Amendment 39-17710 (78 FR 79295,
December 30, 2013), (AD 2013-26-01), for all CFM CFM56-3 and CFM56-7B
model turbofan engines equipped with a certain AGB not equipped with a
handcranking pad oil dynamic assembly. AD 2013-26-01 requires an
independent inspection to verify re-installation of the AGB
handcranking pad cover after any maintenance involving the removal and
reinstallation of the AGB handcranking pad cover. As an optional
terminating action to the inspection requirements, AD 2013-26-01
allowed the installation of an AGB that incorporates a handcranking pad
oil dynamic seal assembly. AD 2013-26-01 resulted from 42 events of
total loss of engine oil from CFM56 model turbofan engines while in
flight. The FAA issued AD 2013-26-01 to prevent loss of engine oil
while in flight, which could result in engine failure, loss of thrust
control, and damage to the airplane.

Actions Since AD 2013-26-01 Was Issued

Since the FAA issued AD 2013-26-01, a dual-engine oil loss event
occurred, prompting the FAA to propose the mandatory installation of a
redesigned handcranking pad oil dynamic seal assembly. In addition, CFM
revised its service information to provide procedures for replacing the
starter drive pad assembly and handcranking cover assembly and for
reworking and reidentifying an affected AGB to a part eligible for
installation.

FAA's Determination

The FAA is issuing this NPRM after determining 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 CFM International CFM56-7B Service Bulletin (SB)
72-0879, Revision 6, dated March 1, 2018 (CFM SB 72-0879); CFM
International SB CFM56-3 SB 72-1129, Revision 7, dated May 5, 2020 (CFM
SB 72-1129); and CFM International SB CFM56-7B SB 72-0564 Revision 8,
dated May 6, 2020 (CFM SB 72-0564). CFM SB 72-1129 describes procedures
for the introduction of a new starter drive pad, new handcranking cover
assembly, and reworking and reidentifying an AGB installed on CFM56-3
model turbofan engines. CFM SB 72-0879 and CFM SB 72-0564 describe
procedures for the introduction of a new starter drive pad, new
handcranking cover, and reworking and reidentifying an AGB installed on
CFM56-7B model turbofan engines. CFM SB 72-0879 and CFM SB 72-0564 are
differentiated by the part numbers of the AGBs eligible for rework and
the new part numbers by which these AGBs will be reidentified once
rework is complete. 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 the ADDRESSES section.

Proposed AD Requirements in This NPRM

This proposed AD would retain certain requirements of AD 2013-26-
01. This proposed AD would require the performance of an independent
inspection to verify re-installation of the AGB handcranking pad cover
after maintenance. Alternatively, this proposed AD would require the
insertion of an independent inspection as a required inspection item in
the approved continuous airworthiness maintenance program for the
aircraft not later than the next time the AGB handcranking pad cover is
removed for maintenance. This proposed AD would also remove the
optional terminating action in AD 2013-26-01 and add a mandatory
terminating action for certain model turbofan engines, requiring the
removal and replacement of an affected AGB with an AGB that
incorporates the oil dynamic seal assembly.

For all CFM56-3B and the majority of CFM56-7B turbofan engine
models, this proposed AD would require replacement of the AGB as a
mandatory terminating action to the inspection requirement of this AD.
This proposed AD does not require this terminating action for CFM56-
7B27A, CFM56-7B27A/3 and CFM56-7B27AE model turbofan engines because
these model engines, which are installed only in military airplanes, do
not have a replacement AGB eligible for installation.

Costs of Compliance

The FAA estimates that this AD, as proposed, would affect 700
engines installed on airplanes of U.S. registry. The FAA estimates that
the majority of operators will perform the repair and reidentification
of the AGB rather than replace the AGB with a zero hour part. For the
purpose of this cost estimate, the FAA estimates that 95% of AGBs will
be repaired and reidentified while 5% of AGBs will be replaced with a
zero hour AGB.

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 has 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 that the 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:

a. Removing airworthiness directive 2013-26-01, Amendment 39-17710 (78
FR 79295, December 30, 2013); and

b. Adding the following new airworthiness directive: