Federal Register / Vol. 89, No. 191 / Wednesday, October 2, 2024 / Proposed Rules 80155 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2024–2325; Project 

Identifier AD–2024–00412–E] 

RIN 2120–AA64 

Airworthiness Directives; CFM 

International, S.A. Engines 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for 

certain CFM International, S.A. (CFM) 

Model LEAP–1A and LEAP–1C engines. 

This proposed AD was prompted by an 

investigation of an in-flight shut down 

event that determined the aft arm of the 

high-pressure turbine (HPT) rotor 

interstage seal had failed. This proposed 

AD would require removal from service 

and replacement of the HPT rotor 

interstage seal for LEAP–1A engines. 

Since the HPT rotor interstage seal part 

number is interchangeable between 

LEAP–1A and LEAP–1C, this proposed 

AD will also prohibit installation of 

these affected parts onto any LEAP–1A 

or LEAP–1C engine. 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 November 18, 

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–2024–2325; 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. 

Material Incorporated by Reference: 

• For CFM material identified in this 

proposed AD, contact CFM, GE Aviation 

Fleet Support, 1 Neumann Way, M/D 

Room 285, Cincinnati, OH 45215; 

phone: (877) 432–3272; email: 

aviation.fleetsupport@ge.com. 

• You may view this material 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 (817) 222– 

5110. 

FOR FURTHER INFORMATION CONTACT: 

Mehdi Lamnyi, Aviation Safety 

Engineer, FAA, 2200 South 216th Street, 

Des Moines, WA 98198; phone: (781) 

238–7743; email: mehdi.lamnyi@

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 the ADDRESSES section. Include 

‘‘Docket No. FAA–2024–2325; Project 

Identifier AD–2024–00412–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 revise 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 

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 Mehdi Lamnyi, 

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 May 19, 2022, an Airbus Model 

A320neo airplane powered by CFM 

Model LEAP–1A26 engines experienced 

an in-flight shutdown. Ground 

inspection following the event found 

that several low-pressure turbine blades 

had broken and metal had entered the 

exhaust. A manufacturer investigation 

later determined that the aft arm of the 

HPT rotor interstage seal had failed due 

to a non-conforming surface condition 

in the fillet area coupled with higherthan-expected operating stress due to 

friction. Three additional engines have 

been reported with shop finds or failure 

of the aft arm of the HPT rotor interstage 

seal. This condition, if not addressed, 

could result in failure of one or more 

engines, loss of thrust control, and loss 

of the airplane. 

FAA’s Determination 

The FAA is issuing this NPRM after 

determining that the unsafe condition 

described previously is likely to exist or 

develop on other products of the same 

type design. 

Material Incorporated by Reference 

Under 1 CFR Part 51 

The FAA reviewed the following CFM 

material: 

• CFM Service Bulletin (SB) LEAP– 

1A–72–00–0525–01A–930A–D, Issue 

002–00, dated June 28, 2024, which 

provides the serial numbers (S/Ns) of 

the affected HPT rotor interstage seals 

for LEAP–1A engines. 

• CFM SB LEAP–1C–72–00–0124– 

01A–930A–D, Issue 001, dated 

September 5, 2024, which provides the 

S/Ns of the affected HPT rotor interstage 

seals that are excluded from installation 

onto LEAP–1C engines. 

This material also includes 

instructions for removal and installation 

of the HPT rotor interstage seal. This 

material 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 require 

removal from service and replacement 

of the HPT rotor interstage seal. 


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80156 Federal Register / Vol. 89, No. 191 / Wednesday, October 2, 2024 / Proposed Rules 

Costs of Compliance 

The FAA estimates that this AD, if 

adopted as proposed, would affect 56 

engines installed on airplanes of U.S. 

registry. 

The FAA estimates the following 

costs to comply with this proposed AD: 

ESTIMATED COSTS

Action Labor cost Parts cost Cost per 

product 

Cost on U.S. 

operators 

Replace HPT rotor interstage seal .............. 12 work-hours × $85 per hour = $1,020 ..... $195,000 $196,020 $10,977,120 

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. 

§ 39.13 [Amended] 

■ 2. The FAA amends § 39.13 by adding 

the following new airworthiness 

directive: 

CFM International, S.A.: Docket No. FAA– 

2024–2325; Project Identifier AD–2024– 

00412–E. 

(a) Comments Due Date 

The FAA must receive comments on this 

airworthiness directive (AD) by November 

18, 2024. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to the following CFM 

International, S.A. (CFM) engines: 

(1) Model LEAP–1A23, LEAP–1A24, 

LEAP–1A24E1, LEAP–1A26, LEAP–1A26CJ, 

LEAP–1A26E1, LEAP–1A29, LEAP–1A29CJ, 

LEAP–1A30, LEAP–1A32, LEAP–1A33, 

LEAP–1A33B2, and LEAP–1A35A engines. 

(2) Model LEAP–1C28, LEAP–1C30, and 

LEAP–1C30B1 engines. 

(d) Subject 

Joint Aircraft System Component (JASC) 

Code 7250, Turbine Section. 

(e) Unsafe Condition 

This AD was prompted by an investigation 

of an in-flight shut down event that 

determined the aft arm of the high-pressure 

turbine (HPT) rotor interstage seal had failed. 

The FAA is issuing this AD to prevent failure 

of the HPT rotor interstage seal. The unsafe 

condition, if not addressed, could result in 

failure of one or more engines, loss of thrust 

control, and loss of the airplane. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Required Actions 

(1) For LEAP–1A engines having an HPT 

rotor interstage seal installed with a part 

number (P/N) and serial number (S/N) listed 

in Table 1 of CFM Service Bulletin (SB) 

LEAP–1A–72–00–0525–01A–930A–D, Issue 

002–00, dated June 28, 2024 (CFM SB LEAP– 

1A–72–00–0525–01A–930A–D Issue 002–00), 

at the next engine shop visit or before 

exceeding the applicable cyclic threshold in 

Table 1 to paragraph (g)(1) of this AD, 

whichever occurs first after the effective date 

of this AD, remove the affected HPT rotor 

interstage seal from service and replace with 

a part eligible for installation. 

TABLE 1 TO PARAGRAPH (g)(1)—REMOVAL THRESHOLDS FOR EACH ENGINE MODEL

Engine model Removal cyclic threshold 

LEAP–1A23, LEAP–1A24, LEAP–1A24E1, LEAP–1A26, LEAP–1A26E1, LEAP–1A29, 

LEAP–1A30, LEAP–1A32, LEAP–1A33, LEAP–1A33B2, and LEAP–1A35A.

11,100 cycles since new (CSN) accumulated on the affected part. 

LEAP–1A26CJ and LEAP–1A29CJ ................................................................................. 9,700 CSN accumulated on the affected part. 

(2) For LEAP–1A engines having an HPT 

rotor interstage seal installed with a P/N and 

S/N listed in Table 2 of CFM SB LEAP–1A– 

72–00–0525–01A–930A–D Issue 002–00, at 

the next piece part exposure or before 

exceeding the applicable cyclic threshold in 

Table 1 to paragraph (g)(1) of this AD, 

whichever occurs first after the effective date 

of this AD, remove the affected HPT rotor 

interstage seal from service and replace with 

a part eligible for installation. 

(h) Installation Prohibition 

(1) After the effective date of this AD, do 

not install an HPT rotor interstage seal 

having a P/N and S/N listed in Table 1 or 

Table 2 of CFM SB LEAP–1A–72–00–0525– 


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Federal Register / Vol. 89, No. 191 / Wednesday, October 2, 2024 / Proposed Rules 80157 

01A–930A–D Issue 002–00, in any LEAP–1A 

engine. 

(2) After the effective date of this AD, do 

not install an HPT rotor interstage seal 

having a P/N and S/N listed in Table 1 of 

CFM SB LEAP–1C–72–00–0124–01A–930A– 

D, Issue 001, dated September 5, 2024, in any 

LEAP–1C engine. 

(i) Definitions 

For the purpose of this AD: 

(1) ‘‘LEAP–1A engines’’ are CFM Model 

LEAP–1A23, LEAP–1A24, LEAP–1A24E1, 

LEAP–1A26, LEAP–1A26CJ, LEAP–1A26E1, 

LEAP–1A29, LEAP–1A29CJ, LEAP–1A30, 

LEAP–1A32, LEAP–1A33, LEAP–1A33B2, 

LEAP–1A35A engines. 

(2) ‘‘LEAP–1C engines’’ are CFM Model 

LEAP–1C28, LEAP–1C30, and LEAP–1C30B1 

engines. 

(3) A ‘‘part eligible for installation’’ is any 

HPT rotor interstage seal having a P/N and 

S/N that is not listed in Table 1 or Table 2 

of CFM SB LEAP–1A–72–00–0525–01A– 

930A–D Issue 002–00. 

(4) An ‘‘engine shop visit’’ is the induction 

of an engine into the shop for maintenance 

involving the separation of major mating 

engine flanges, except for the separation of 

engine flanges solely for the purposes of 

transportation without subsequent engine 

maintenance. 

(5) A ‘‘piece-part exposure’’ is when the 

HPT rotor interstage seal is separated from 

the HPT rotor assembly. 

(j) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, AIR–520 Continued 

Operational Safety 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 AIR–520 Continued 

Operational Safety Branch, send it to the 

attention of the person identified in 

paragraph (k)(1) of this AD and email to: 

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. 

(k) Additional Information 

For more information about this AD, 

contact Mehdi Lamnyi, Aviation Safety 

Engineer, FAA, 2200 South 216th Street, Des 

Moines, WA 98198; phone: (781) 238–7743; 

email: mehdi.lamnyi@faa.gov. 

(l) Material Incorporated by Reference 

(1) The Director of the Federal Register 

approved the incorporation by reference 

(IBR) of the material listed in this paragraph 

under 5 U.S.C. 552(a) and 1 CFR part 51. 

(2) You must use this material as 

applicable to do the actions required by this 

AD, unless the AD specifies otherwise. 

(i) CFM International, S.A. (CFM) Service 

Bulletin LEAP–1A–72–00–0525–01A–930A– 

D, Issue 002–00, dated June 28, 2024. 

(ii) CFM Service Bulletin LEAP–1C–72– 

00–0124–01A–930A–D, Issue 001, dated 

September 5, 2024. 

(3) For CFM material identified in this AD, 

contact CFM, GE Aviation Fleet Support, 1 

Neumann Way, M/D Room 285, Cincinnati, 

OH 45215; phone: (877) 432–3272; email: 

aviation.fleetsupport@ge.com. 

(4) You may view this material 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 (817) 222–5110. 

(5) You may view this material at the 

National Archives and Records 

Administration (NARA). For information on 

the availability of this material at NARA, 

visit www.archives.gov/federal-register/cfr/ 

ibr-locations or email fr.inspection@nara.gov. 

Issued on September 27, 2024. 

Peter A. White, 

Deputy Director, Integrated Certificate 

Management Division, Aircraft Certification 

Service. 

[FR Doc. 2024–22600 Filed 10–1–24; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 71 

[Docket No. FAA–2024–2268; Airspace 

Docket No. 24–AAL–95] 

RIN 2120–AA66 

Revocation of Alaskan Very High 

Frequency Omnidirectional Range 

Federal Airway V–447 and Jet Route J– 

155 and Amendment of Jet Route J– 

115 in Alaska 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: This action proposes to 

revoke Alaskan Very High Frequency 

Omnidirectional Range (VOR) Federal 

Airway V–447 and Jet Route J–155 and 

amend Jet Route J–115 in Alaska. These 

proposed actions are due to the 

decommissioning of the Chandalar Lake 

Nondirectional Radio Beacon (NDB) in 

Alaska. 

DATES: Comments must be received on 

or before November 18, 2024. 

ADDRESSES: Send comments identified 

by FAA Docket No. FAA–2024–2268 

and Airspace Docket No. 24–AAL–95 

using any of the following methods: 

* Federal eRulemaking Portal: Go to 

www.regulations.gov and follow the 

online instructions for sending your 

comments electronically. 

* Mail: Send comments to Docket 

Operations, M–30; U.S. Department of 

Transportation, 1200 New Jersey 

Avenue SE, Room W12–140, West 

Building Ground Floor, Washington, DC 

20590–0001. 

* Hand Delivery or Courier: Take 

comments to Docket Operations in 

Room W12–140 of the West Building 

Ground Floor at 1200 New Jersey 

Avenue SE, Washington, DC, between 9 

a.m. and 5 p.m., Monday through 

Friday, except Federal holidays. 

* Fax: Fax comments to Docket 

Operations at (202) 493–2251. 

Docket: Background documents or 

comments received may be read at 

www.regulations.gov at any time. 

Follow the online instructions for 

accessing the docket or go to the Docket 

Operations in Room W12–140 of the 

West Building Ground Floor at 1200 

New Jersey Avenue SE, Washington, 

DC, between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

FAA Order JO 7400.11J, Airspace 

Designations and Reporting Points, and 

subsequent amendments can be viewed 

online at www.faa.gov/air_traffic/ 

publications/. You may also contact the 

Rules and Regulations Group, Office of 

Policy, Federal Aviation 

Administration, 600 Independence 

Avenue SW, Washington, DC 20597; 

telephone: (202) 267–8783. 

FOR FURTHER INFORMATION CONTACT: 

Steven Roff, Rules and Regulations 

Group, Office of Policy, Federal 

Aviation Administration, 600 

Independence Avenue SW, Washington, 

DC 20597; telephone: (202) 267–8783. 

SUPPLEMENTARY INFORMATION: 

Authority for This Rulemaking 

The FAA’s authority to issue rules 

regarding aviation safety is found in 

Title 49 of the United States Code. 

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. This rulemaking is 

promulgated under the authority 

described in Subtitle VII, Part A, 

Subpart I, Section 40103. Under that 

section, the FAA is charged with 

prescribing regulations to assign the use 

of the airspace necessary to ensure the 

safety of aircraft and the efficient use of 

airspace. This regulation is within the 

scope of that authority as it would 

modify the airway structure as 

necessary to preserve the safe and 

efficient flow of air traffic within the 

National Airspace System. 

Comments Invited 

The FAA invites interested persons to 

participate in this rulemaking by 

submitting written comments, data, or 


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