Proposed Rules. Notice of proposed rulemaking (NPRM)

Agency: Federal Aviation Administration (FAA), DOT
Action: Notice of proposed rulemaking (NPRM)
Citation: FR Doc. 2025-17732 · RIN 2120-AA64 · Docket No. FAA-2025-2543; Project Identifier MCAI-2025-00215-T · 14 CFR 39

Summary

The FAA proposes to adopt a new airworthiness directive (AD) for certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. This proposed AD was prompted by the discovery that titanium fasteners had been incorrectly installed in the butt strap at the outer wing box lower skin to center wing box interface in lieu of the correct nickel alloy fasteners. This proposed AD would require the identification of fasteners installed in the butt strap at the outer wing box lower skin to center wing box interface, and applicable on-condition actions. 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 October 30, 2025.

Supplementary Information

Comments Invited The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments using a method listed under the ADDRESSES section. Include “Docket No. FAA-2025-2543; Project Identifier MCAI-2025-00215-T” 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 Aryanna Sanchez, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 817-222-4058; email: aryanna.t.sanchez@faa.gov . Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking. Background Transport Canada, which is the aviation authority for Canada, has issued Transport Canada AD CF-2025-09, dated February 24, 2025 (Transport Canada AD CF-2025-09) (also referred to as the MCAI), to correct an unsafe condition for certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. The MCAI states that titanium fasteners (part number (P/N) B0206003GD) had been incorrectly installed in the butt strap at the outer wing box lower skin to center wing box interface in lieu of the correct nickel alloy fasteners (P/N B0206033GD). The use of titanium fasteners could result in a reduction in joint strength, and the risk of a fuel leak if the fastener fails and falls free from the joint. This condition, if not corrected, could cause damage to and loss of principal structure and fatigue critical structure. The FAA is proposing this AD to address the unsafe condition on these products. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-2543. Material Incorporated by Reference Under 1 CFR Part 51 Transport Canada AD CF-2025-09 specifies procedures for a detailed inspection to identify the part markings on the head of the fasteners, and applicable on-condition actions. On-condition actions include replacing non-serviceable fasteners (those not identified as HST54, HST154, HST254, B0201074, B0201074 with oversize code X, or B0201074 with oversize code Y). For non-serviceable fasteners, the replacement includes a detailed inspection to make sure that the fastener heads are not damaged; the fastener heads are installed within requirements; and there are no signs of loose fasteners, fasteners that rotated, or fasteners that moved. 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. FAA's Determination These products have been approved by the civil aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI referenced above. 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. Proposed AD Requirements in This NPRM This proposed AD would require accomplishing the actions specified in Transport Canada AD CF-2025-09 described previously, except for any differences identified as exceptions in the regulatory text of this proposed AD. Explanation of Required Compliance Information In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, the FAA proposes to incorporate Transport Canada AD CF-2025-09 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with Transport Canada AD CF-2025-09 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD. Material required by Transport Canada AD CF-2025-09 for compliance will be available at regulations.gov under Docket No. FAA-2025-2543 after the FAA final rule is published. Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect 79 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD: Estimated Costs for Required Actions Labor cost Parts cost Cost per product Cost on U.S. operators 29 work-hours × $85 per hour = $2,465 $0 $2,465 $194,735 The FAA estimates the following costs to do any necessary on-condition actions that would be required based on the results of any required actions. The FAA has no way of determining the number of aircraft that might need this on-condition action: Estimated Costs of On-Condition Actions Labor cost Parts cost Cost per product Up to 4 work-hours × $85 per hour = $340 Up to $11,550 Up to $11,890 (for 11 fasteners). The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some or all of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected operators. 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: Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.): Docket No. FAA-2025-2543; Project Identifier MCAI-2025-00215-T. (a) Comments Due Date The FAA must receive comments on this airworthiness directive (AD) by October 30, 2025. (b) Affected ADs None. (c) Applicability This AD applies to Airbus Canada Limited Partnership (Type Certificate previously held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Model BD-500-1A10 and BD-500-1A11 airplanes, certificated in any category, as identified in Transport Canada AD CF-2025-09, dated February 24, 2025 (Transport Canada AD CF-2025-09). (d) Subject Air Transport Association (ATA) of America Code 57, Wings. (e) Unsafe Condition This AD was prompted by the discovery that titanium fasteners had been incorrectly installed in the butt strap at the outer wing box lower skin to center wing box interface in lieu of the correct nickel alloy fasteners. The FAA is issuing this AD to address the use of titanium fasteners. The unsafe condition, if not addressed, could result in a reduction in joint strength, potential damage to and loss of principal structure and fatigue critical structure, and the risk of a fuel leak if the fastener fails and falls free from the joint. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Requirements Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, Transport Canada AD CF-2025-09. (h) Exceptions to Transport Canada AD CF-2025-09 (1) Where Transport Canada AD CF-2025-09 refers to its effective date, this AD requires using the effective date of this AD. (2) Where Transport Canada AD CF-2025-09 refers to “10000 flight cycles”, this AD requires replacing that text with “10,000 total flight cycles.” (i) No Reporting Requirement Although the material referenced in Transport Canada AD CF-2025-09 specifies to submit certain information to the manufacturer, this AD does not include that requirement. (j) Additional AD Provisions The following provisions also apply to this AD: (1) Alternative Methods of Compliance (AMOCs): 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 responsible Flight Standards Office, as appropriate. If sending information directly to the manager of the Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (k) of this AD and email to: AMOC@faa.gov . Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office. (2) Contacting the Manufacturer: For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, AIR-520, Continued Operational Safety Branch, FAA; or Transport Canada; or Transport Canada; or Airbus Canada Limited Partnership's Transport Canada Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature. (k) Additional Information For more information about this AD, contact Aryanna Sanchez, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 817-222-4058; email: aryanna.t.sanchez@faa.gov . (l) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference 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 this AD specifies otherwise. (i) Transport Canada AD CF-2025-09, dated February 24, 2025. (ii) [Reserved] (3) For Transport Canada material identified in this AD, contact Transport Canada, Transport Canada National Aircraft Certification, 159 Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada; telephone 888-663-3639; email TC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca . You may find this material on the Transport Canada website at tc.canada.ca/en/aviation . (4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. (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 10, 2025. Peter A. White, Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service. [FR Doc. 2025-17732 Filed 9-12-25; 8:45 am]