Airworthiness Directives; Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Airplanes

DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-5024; Project Identifier MCAI-2025-00797-T]</DEPDOC> <RIN>RIN 2120-AA64</RIN> <SUBJECT>Airworthiness Directives; Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Airplanes</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Federal Aviation Administration (FAA), DOT. <HD SOURCE="HED">ACTION:</HD> Notice of proposed rulemaking (NPRM). <SUM> <HD SOURCE="HED">SUMMARY:</HD> The FAA proposes to supersede Airworthiness Directive (AD) 2024-04-06, which applies to certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. AD 2024-04-06 requires repetitive operational checks of the gravity cross flow shut-off valve and, for certain airplanes, a one-time inspection of the motive flow fuel-feed tubes at the clamp blocks location, and applicable corrective action. Since the FAA issued AD 2024-04-06, the manufacturer developed additional corrective actions. This proposed AD would continue to require the actions in AD 2024-04-06 and would require replacement of the saddle clamp, inspection of the motive flow fuel-feed tubes, and applicable corrective actions. The FAA is proposing this AD to address the unsafe condition on these products. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> The FAA must receive comments on this proposed AD by January 5, 2026. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods: • <E T="03">Federal eRulemaking Portal:</E> Go to <E T="03">regulations.gov</E> . Follow the instructions for submitting comments. • <E T="03">Fax:</E> 202-493-2251. • <E T="03">Mail:</E> U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. • <E T="03">Hand Delivery:</E> Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. <E T="03">AD Docket:</E> You may examine the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-5024; 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, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The street address for Docket Operations is listed above. <E T="03">Material Incorporated by Reference:</E> • For Transport Canada material identified in this proposed AD, contact Transport Canada, Transport Canada National Aircraft Certification, 159 Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada; telephone 888-663-3639; email <E T="03">TC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca</E> . You may find this material on the Transport Canada website at <E T="03">tc.canada.ca/en/aviation.</E> It is also available at <E T="03">regulations.gov</E> under Docket No. FAA-2025-5024. • 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. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Erica Bayles, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 907-271-5844; email: <E T="03">erica.e.bayles@faa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">Comments Invited</HD> 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 <E T="02">ADDRESSES</E> section. Include “Docket No. FAA-2025-5024; Project Identifier MCAI-2025-00797-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 <E T="03">regulations.gov</E> , including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM. <HD SOURCE="HD1">Confidential Business Information</HD> 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 Erica Bayles, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 907-271-5844; email: <E T="03">erica.e.bayles@faa.gov.</E> Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking. <HD SOURCE="HD1">Background</HD> The FAA issued AD 2024-04-06, Amendment 39-22685 (89 FR 19228, March 18, 2024) (AD 2024-04-06), for certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. AD 2024-04-06 was prompted by an MCAI originated by Transport Canada, which is the aviation authority for Canada. Transport Canada issued AD CF-2022-70, dated December 21, 2022, to correct an unsafe condition. AD 2024-04-06 requires repetitive operational checks of the gravity cross flow shut-off valve and, for certain airplanes, a one-time inspection of the motive flow fuel-feed tubes at the clamp blocks location, and applicable corrective action. The FAA issued AD 2024-04-06 to address mechanical wear damage on the motive flow fuel-feed tubes. <HD SOURCE="HD1">Actions Since AD 2024-04-06 Was Issued</HD> AD 2024-04-06 explains that the FAA considers the requirements “interim action” and was considering further rulemaking. The FAA has now determined that further rulemaking is necessary, and this proposed AD follows from that determination. Since the FAA issued AD 2024-04-06, Transport Canada superseded AD CF-2022-70, dated December 21, 2022, and issued Transport Canada AD CF-2025-24, dated April 29, 2025 (Transport Canada AD CF-2025-24) (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 there have been several findings of mechanical wear damage on the motive flow fuel-feed tubes that were secured by bonding clamps and clamp blocks inside the collector tank. In some instances, the wear damage led to a hole in a motive flow fuel-feed tube resulting in a fuel imbalance during flight that required the flightcrews to correct the imbalance using the gravity transfer system. Failure of the affected motive flow fuel-feed tubes and a subsequent failure of the gravity transfer system could lead to a fuel imbalance condition resulting in a reduction in airplane functional capabilities and increased crew workload. The MCAI also states that since AD CF-2022-70 was issued, the manufacturer issued new service information to require replacement of the saddle clamp of the motive flow tubes, along with an inspection and rectification of the flow fuel-feed tubes. The FAA is proposing this AD to address the unsafe condition on these products. You may examine the MCAI in the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-5024. <HD SOURCE="HD1">Explanation of Retained Requirements</HD> Although this proposed AD does not explicitly restate the requirements of AD 2024-04-06, this proposed AD would retain all of the requirements of AD 2024-04-06. Those requirements are referenced in Transport Canada AD CF-2025-24, which, in turn, is referenced in paragraph (g) of this proposed AD. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> The FAA reviewed Transport Canada AD CF-2025-24, which specifies procedures for performing a repetitive operational check of the gravity cross flow shut-off valve and, for certain airplanes, inspecting the motive flow fuel-feed tubes for mechanical wear damage (damage includes, but is not limited to, cracks, scores, scratches, nicks, and gouges) and pre-load condition, and, based on findings, replacing the motive flow fuel-feed tube. This material also specifies procedures for replacing the saddle clamp of the motive flow fuel-feed tubes on both left and right sides, inspecting the motive flow fuel-feed tubes for damage (damage includes, but is not limited to, cracks, scores, scratches, nicks, and gouges) and, based on findings, repairing or replacing the motive flow fuel-feed tube. 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 <E T="02">ADDRESSES</E> section. <HD SOURCE="HD1">FAA's Determination</HD> 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 ag ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 23k characters. 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