2022-26121. Airworthiness Directives; CFM International, S.A. Turbofan 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) LEAP-1B turbofan engines. This proposed AD was prompted by a report of multiple aborted takeoffs and air turn-backs (ATBs) caused by high-pressure compressor (HPC) stall, which was induced by high levels of non-synchronous vibration (NSV). A subsequent investigation by the manufacturer revealed that wear on the No. 3 bearing spring finger housing can lead to high levels of NSV. This proposed AD would require repetitive calculations of the oil filter delta pressure (OFDP) data and, depending on the results of the calculation, replacement of the No. 3 bearing spring finger housing. This proposed AD would also prohibit installation of an engine with an affected No. 3 bearing spring finger housing onto an airplane that already has one engine with an affected No. 3 bearing spring finger housing installed. 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 January 17, 2023.

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: [phone].

• 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 by searching for and locating Docket No. FAA-2022-1422; 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 service information identified in this NPRM, contact CFM International Inc., Aviation Operations Center, 1 Neumann Way, M/D Room 285, Cincinnati, OH 45125; phone: [phone]; email: [e-mail].

• 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 [phone].

FOR FURTHER INFORMATION CONTACT:

Mehdi Lamnyi, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: [phone]; email: [e-mail].

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-2022-1422; Project Identifier AD-2022-01208-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 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, 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 was notified by the engine manufacturer of three aborted takeoffs and two ATBs caused by HPC stall. A subsequent investigation by the manufacturer revealed that wear on the No. 3 bearing spring finger housing can lead to high levels of NSV, which could induce HPC stall. This wear manifests itself early on as higher than typical OFDP loading. As a result of its investigation, the manufacturer published service information that specifies procedures for calculating the OFDP data and replacing the affected No. 3 bearing spring finger housing. This condition, if not addressed, could result in engine power loss at a critical phase of flight such as takeoff or climb, loss of thrust control, reduced controllability of the airplane, 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.

Related Service Information Under 1 CFR Part 51

The FAA reviewed CFM Service Bulletin LEAP-1B-72-00-0369-01A-930A-D, Issue 001-00, dated August 22, 2022. This service information specifies procedures for calculating the OFDP data and replacing the affected No. 3 bearing spring finger housing. This service information also identifies the serial numbers of the affected No. 3 bearing spring finger housings installed on LEAP-1B 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 .

Proposed AD Requirements in This NPRM

This proposed AD would require a calculation of the OFDP data and, depending on the results of the calculation, replacement of the No. 3 bearing spring finger housing. This proposed AD would also prohibit the installation of an engine with an affected No. 3 bearing spring finger housing onto an airplane that already has one engine with an affected No. 3 bearing spring finger housing installed.

Interim Action

The FAA considers that this proposed AD would be an interim action. The design approval holder is currently developing a modification that will address the unsafe condition identified in this proposed AD. Once this modification is developed, approved, and available, the FAA might consider additional rulemaking.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 8 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
Calculate OFDP data	1 work-hour × $85 per hour = $85	$0	$85	$680
Replace No. 3 bearing spring finger housing	17 work-hours × $85 per hour = $1,445	64,590	66,035	528,280

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-2022-1422; Project Identifier AD-2022-01208-E.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by January 17, 2023.

(b) Affected ADs

None.

(c) Applicability

This AD applies to CFM International, S.A. (CFM) LEAP-1B21, LEAP-1B23, LEAP-1B25, LEAP-1B27, LEAP-1B28, LEAP-1B28B1, LEAP-1B28B2, LEAP-1B28B2C, LEAP-1B28B3, LEAP-1B28BBJ1, and LEAP-1B28BBJ2 model turbofan engines with an installed No. 3 bearing spring finger housing, part number (P/N) 2542M54G01, and serial number (S/N) identified in Table 1 of CFM Service Bulletin (SB) LEAP-1B-72-00-0369-01A-930A-D, Issue 001-00, dated August 22, 2022 (CFM LEAP-1B-72-00-0369-01A-930A-D).

(d) Subject

Joint Aircraft System Component (JASC) Code 7230, Turbine Engine Compressor Section.

(e) Unsafe Condition

This AD was prompted by a report of multiple aborted takeoffs and air turn-backs (ATBs) caused by high-pressure compressor (HPC) stall, which was induced by high levels of non-synchronous vibration (NSV), and a subsequent investigation by the manufacturer that revealed wear on the No. 3 bearing spring finger housing. The FAA is issuing this AD to prevent HPC stall. The unsafe condition, if not addressed, could result in engine power loss at a critical phase of flight such as takeoff or climb, loss of thrust control, reduced controllability of the airplane, and loss of the airplane.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Required Actions

(1) Before the affected No. 3 bearing spring finger housing accumulates 125 flight cycles (FCs) since new, but not before accumulating 75 FCs since new, or within 50 FCs after the effective date of this AD, whichever occurs later, calculate the oil filter delta pressure (OFDP) data in accordance with the Accomplishment Instructions, paragraphs 5.A.(1) through 5.A.(2) or 5.B.(1) through 5.B.(2), of CFM LEAP-1B-72-00-0369-01A-930A-D.

(2) Thereafter, at intervals not to exceed 100 FCs from the last calculation of the OFDP data, and until the affected No. 3 bearing spring finger housing accumulates 1,000 FCs since new, repeat the calculation required by paragraph (g)(1) of this AD.

(3) If, during the calculation required by paragraph (g)(1) or (2) of this AD, the OFDP data exceed the limits specified in the Accomplishment Instructions, paragraph 5.A.(3) or 5.B.(3), of CFM LEAP-1B-72-00-0369-01A-930A-D, as applicable, within 25 FCs of performing the calculation, replace the affected No. 3 bearing spring finger housing with a part eligible for installation.

(4) During the next engine shop visit after the effective date of this AD, replace the affected No. 3 bearing spring finger housing with a part eligible for installation.

(h) Terminating Action

Replacement of the affected No. 3 bearing spring finger housing with a part eligible for installation, as specified in paragraphs (g)(3) and (g)(4) of this AD, constitutes terminating action for the calculations required by paragraphs (g)(1) and (2) of this AD.

(i) Installation Prohibition

After the effective date of this AD, do not install an engine with an affected No. 3 bearing spring finger housing onto an airplane that already has one engine with an affected No. 3 bearing spring finger housing installed.

(j) Definition

For the purpose of this AD, a “part eligible for installation” is a No. 3 bearing spring finger housing that is not identified in Table 1 of CFM LEAP-1B-72-00-0369-01A-930A-D.

(k) 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 paragraph (l) of this AD and email it to: [e-mail].

(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.

(l) Related Information

For more information about this AD, contact Mehdi Lamnyi, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: [phone]; email: [e-mail].

(m) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise.

(i) CFM Service Bulletin LEAP-1B-72-00-0369-01A-930A-D, Issue 001-00, dated August 22, 2022.

(ii) [Reserved]

(3) For CFM service information identified in this AD, contact CFM International Inc., Aviation Operations Center, 1 Neumann Way, M/D Room 285, Cincinnati, OH 45125; phone: [phone]; email: [e-mail].

(4) You may view this service information at 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 [phone].

(5) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, email: [e-mail], or go to: www.archives.gov/​federal-register/​cfr/​ibr-locations.html.

Issued on November 9, 2022.

Christina Underwood,

Acting Director, Compliance & Airworthiness Division, Aircraft Certification Service.