DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0760; Project Identifier AD-2024-00175-E;
Amendment 39-22714; AD 2024-06-09]
RIN 2120-AA64

Airworthiness Directives; CFM International, S.A. Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain CFM International, S.A. (CFM) Model CFM56-2, CFM56-3, CFM56-5,
CFM56-5B, CFM56-5C, and CFM56-7B engines. This AD was prompted by a
report of electrical arcing on certain life-limited critical parts.
This AD requires replacing certain compressor discharge pressure (CDP)
seals, high-pressure compressor (HPC) stage 3 disks, and high-pressure
turbine (HPT) rear shafts. This AD also prohibits installation of
certain CDP seals, HPC stage 3 disks, and HPT rear shafts on any
engine, and prohibits installation of any engine with certain CDP
seals, HPC stage 3 disks, and HPT rear shafts installed on any
airplane. The FAA is issuing this AD to address the unsafe condition on
these products.

DATES: This AD is effective March 25, 2024.
The FAA must receive comments on this AD by May 6, 2024.

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 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.
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2024-0760; 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, any comments received, and other
information. The street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Sungmo Cho, Aviation Safety Engineer,
FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (781) 238-
7241; email: sungmo.d.cho@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written data, views, or arguments
about this final rule. Send your comments to an address listed under
ADDRESSES. Include ``FAA-2024-0760; Project Identifier AD-2024-00175-
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
final rule 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
regulations.gov, including any personal information you provide. The
agency will also post a report summarizing each substantive verbal
contact received about this final rule.

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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Sungmo
Cho, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des
Moines, WA 98198. Any commentary that the FAA receives which is not
specifically designated as CBI will be placed in the public docket for
this rulemaking.

Background

On March 7, 2024, the FAA received a report of electrical arcing on
certain life-limited critical parts for CFM Model CFM56-2, CFM56-3,
CFM56-5, CFM56-5B, CFM56-5C, and CFM56-7B engines. A maintenance
facility reported evidence of electrical arcing and identified the root
cause as the use of a certain induction heater during maintenance,
which resulted in unintended electrical arcing to those parts. The
manufacturer determined that certain CDP seals, HPC stage 3 disks, and
HPT rear shafts were subject to the same induction heater during
maintenance and may also have electrical arcing damage. This condition,
if not addressed, could result in premature fracture of certain CDP
seals, HPC stage 3 disks, and HPT rear shafts, with consequent
uncontained part release, damage to the engine, damage to the airplane,
and loss of the airplane. The FAA is issuing this AD to address the
unsafe condition on these products.

FAA's Determination

The FAA is issuing this AD because the agency has determined the
unsafe condition described previously is likely to exist or develop in
other products of the same type design.

AD Requirements

This AD requires replacing certain CDP seals, HPC stage 3 disks,
and HPT rear shafts. This AD also prohibits installation of certain CDP
seals, HPC stage 3 disks, and HPT rear shafts on any engine, and
prohibits installation of any engine with certain CDP seals, HPC
stage 3 disks, and HPT rear shafts installed on any airplane.

Justification for Immediate Adoption and Determination of the Effective
Date

Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5
U.S.C. 551 et seq.) authorizes agencies to dispense with notice and
comment procedures for rules when the agency, for ``good cause,'' finds
that those procedures are ``impracticable, unnecessary, or contrary to
the public interest.'' Under this section, an agency, upon finding good
cause, may issue a final rule without providing notice and seeking
comment prior to issuance. Further, section 553(d) of the APA
authorizes agencies to make rules effective in less than thirty days,
upon a finding of good cause.
An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies forgoing notice and comment prior to adoption of this rule
due to maintenance anomalies that could result in premature fracture of
certain life-limited critical parts, with consequent uncontained part
release, damage to the engine, damage to the airplane, and loss of the
airplane. The compliance time for replacement of these parts is before
further flight after the effective date of this AD. The longer these
parts remain in service, the higher the probability of failure.
Accordingly, notice and opportunity for prior public comment are
impracticable and contrary to the public interest pursuant to 5 U.S.C.
553(b)(3)(B).
In addition, the FAA finds that good cause exists pursuant to 5
U.S.C. 553(d) for making this amendment effective in less than 30 days,
for the same reasons the FAA found good cause to forgo notice and
comment.

Regulatory Flexibility Act

The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because FAA has determined
that it has good cause to adopt this rule without prior notice and
comment, RFA analysis is not required.

Costs of Compliance

The FAA estimates that this AD affects 3 engines installed on
airplanes of U.S. registry. The FAA estimates that three engines
installed on airplanes of U.S. registry require replacement of the CDP
seal. The FAA estimates that two engines installed on airplanes of U.S.
registry require replacement of the HPC stage 3 disk and HPT rear
shaft.
The FAA estimates the following costs to comply with this 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

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 that this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866, and
(2) Will not affect intrastate aviation in Alaska.

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

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: