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-2025-0199; Project Identifier MCAI-2024-00332-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> Supplemental notice of proposed rulemaking (SNPRM). <SUM> <HD SOURCE="HED">SUMMARY:</HD> The FAA is revising a notice of proposed rulemaking (NPRM) that would have applied to certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. This action revises the NPRM by adding a requirement to re-identify the ceiling panel liners. The FAA is proposing this airworthiness directive (AD) to address the unsafe condition on these products. Since these actions would impose an additional burden over those in the NPRM, the FAA is requesting comments on this SNPRM. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> The FAA must receive comments on this SNPRM by November 10, 2025. </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-2025-0199; 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 SNPRM, 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 regulations.gov under Docket No. FAA-2025-0199. • 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> Brenda L. Buitrago, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 516-288-7368; email: <E T="03">Brenda.L.Buitrago.Perez@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-2025-0199; Project Identifier MCAI-2024-00332-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 SNPRM. <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 SNPRM 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 SNPRM, 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 SNPRM. Submissions containing CBI should be sent to Brenda L. Buitrago, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 516-288-7368; email: <E T="03">Brenda.L.Buitrago.Perez@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 an NPRM to amend 14 CFR part 39 by adding an AD that would have applied to certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. The NPRM was published in the <E T="04">Federal Register</E> on February 13, 2025 (90 FR 9526). The NPRM was prompted by AD CF-2024-21, dated June 20, 2024 (Transport Canada AD CF-2024-21), issued by Transport Canada, which is the aviation authority for Canada. Transport Canada AD CF-2024-21 states that environmental control system (ECS) ducts, located on forward and aft cargo compartment ceiling panels, having part numbers (P/Ns) D761189-105, D761189-501, and D762232-509, have been manufactured using material APF1180-7781, which replaced discontinued legacy material Solvay L591PG-7781. The material change to APF1180-7781 was done without changing the ECS duct part number. Subsequent certification testing of the ECS ducts made using material APF1180-7781 failed flammability test requirements. These noncompliant ECS ducts may have been installed on certain affected airplanes during production. Noncompliant ECS ducts could result in the inability to contain a fire within the cargo compartment, which could result in an uncontrolled fire. In the NPRM, the FAA proposed to require inspecting the affected ECS ducts and, as applicable, installing a fire-resistant sleeve assembly over any non-compliant ECS duct, and prohibit the installation of ECS ducts as replacement parts under certain conditions. <HD SOURCE="HD1">Actions Since the NPRM Was Issued</HD> Since the FAA issued the NPRM, Transport Canada superseded Transport Canada AD CF-2024-21 and issued Transport Canada AD CF-2025-10, dated February 27, 2025 (Transport Canada AD CF-2025-10) (also referred to as the MCAI), to correct an unsafe condition for all Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. The MCAI states that since Transport Canada AD CF-2024-21 was issued, Airbus Canada revised the instructions in their service information to include a requirement to identify the ceiling panel liners to ensure configuration control. The FAA is proposing this AD to address noncompliant ECS ducts that could cause an inability to contain a fire within the cargo compartment. The unsafe condition, if not addressed, could result in an uncontrolled fire. You may examine the MCAI in the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-0199. <HD SOURCE="HD1">Comments</HD> The FAA received comments from the Air Line Pilots Association, International (ALPA) and two individuals who supported the NPRM without change. The FAA received additional comments from Delta Air Lines (Delta). The following presents the comments received on the NPRM and the FAA's response to each comment. <HD SOURCE="HD1">Request To Reference Transport Canada AD CF-2025-10</HD> Delta requested that the proposed AD be updated to incorporate Transport Canada AD CF-2025-10, which supersedes Transport Canada AD CF-2024-21 and requires additional identification of the ceiling panel liners in affected cargo compartments for airplanes that already incorporated corrective actions. Delta added that Transport Canada AD CF-2025-10 updates the definition of the applicable service information to reference revision 3. The FAA agrees. As previously stated, the FAA has revised this proposed AD to reference Transport Canada AD CF-2025-10. <HD SOURCE="HD1">Request for a 60-Day Grace Period</HD> Delta requested the inclusion of a 60-day grace period in paragraph (h) of the proposed AD. Delta stated the requested 60-day grace period is intended to address Delta aircraft that would be approaching/exceeding the 9,350 total flight hours compliance time when the FAA AD is published. Delta stated it owns three aircraft that need to accomplish the modification required by the proposed AD, and that without a grace period, those aircraft would be grounded. Delta noted that it found many issues with the service information that needed to be reconciled, and a 60-day grace period would allow adequate time to schedule the aircraft into a hanger and to procure parts and materials. The FAA agrees with the commenter's request for a grace period, but has determined that a 30 day grace period will allow operators adequate time to plan and procure parts and materials. The FAA has added paragraph ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 28k characters. 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