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

<RULE> DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2024-2019; Project Identifier MCAI-2023-00909-T; Amendment 39-22994; AD 2025-06-06]</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> Final rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The FAA is adopting a new airworthiness directive (AD) for certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. This AD was prompted by a design review that found insufficient clearance between fire extinguishing system (FIREX) lines and certain fasteners in the center mid-fuselage area. This AD requires an inspection for positioning and sufficient clearance of certain fasteners in certain fuselage and keel beam areas, an inspection for damage of the fire extinguishing lines, and applicable corrective actions, as specified in a Transport Canada AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> This AD is effective May 2, 2025. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of May 2, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> <E T="03">AD Docket:</E> You may examine the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2024-2019; 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 final rule, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The address for Docket Operations is 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">Material Incorporated by Reference:</E> • 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 <E T="03">TC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca</E> . You may view this material on the Transport Canada website at <E T="03">tc.canada.ca/en/aviation.</E> • 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. It is also available at <E T="03">regulations.gov</E> under Docket No. FAA-2024-2019. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Yaser Osman, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone 516-228-7300; email <E T="03">9-avs-nyaco-cos@faa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">Background</HD> The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. The NPRM published in the <E T="04">Federal Register</E> on August 22, 2024 (89 FR 67910). The NPRM was prompted by AD CF-2023-58, dated July 25, 2023 (Transport Canada AD CF-2023-58) (also referred to as the MCAI), issued by Transport Canada, which is the aviation authority for Canada. The MCAI states that a design review found insufficient clearance between FIREX lines and the nuts of the Hi-Lite fasteners in the center mid-fuselage in locations where the fastener nut is on the same side as the FIREX lines. Fouling between the FIREX lines and the Hi-Lite fasteners could lead to a rupture of the line. This would result in a dormant failure of the cargo compartment fire extinguishing system, preventing the system from being available in the event of a cargo compartment fire. In the NPRM, the FAA proposed to require an inspection for positioning and sufficient clearance of certain fasteners in certain fuselage and keel beam areas, an inspection for damage of the fire extinguishing lines, and applicable corrective actions, as specified in Transport Canada AD CF-2023-58. The FAA is issuing 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-2024-2019. <HD SOURCE="HD1">Discussion of Final Airworthiness Directive</HD> <HD SOURCE="HD1">Comments</HD> The FAA received a comment from the Air Line Pilots Association, International (ALPA) 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 Delete Grace Period</HD> Delta pointed out that with the revisions in paragraphs (h)(1) and (2) of the proposed AD providing up to 24 months after the effective date of the AD, paragraph (h)(3)(ii) of the proposed AD becomes moot. The FAA disagrees. The compliance time stated in Transport Canada AD CF-2023-58 is within 24 months after the effective date of Transport Canada AD CF-2023-58 or 17,000 total accumulated flight hours since new, whichever occurs first. There is a chance that an airplane could reach 17,000 total flight hours before the effective date of this AD or soon after. In that case, the 90 days stated in paragraph (h)(3)(ii) of this AD provide a grace period to comply with the requirements of this AD without grounding the airplane. The FAA has not revised this AD as a result of this comment. <HD SOURCE="HD1">Request To Correct Part Numbers</HD> Delta requested an additional sub-paragraph to paragraph (h) of the proposed AD to provide corrections for incorrect part numbers referenced in a service bulletin. The FAA agrees that there are typographical errors for certain items identified in Sheets 5 and 7 in Figure 2 of the Airbus Canada Service Bulletin BD500-534006, Issue 003, dated March 20, 2024, and that those errors can create a challenge for an operator trying to comply with the accomplishment instructions. The FAA has added paragraph (h)(4) of this AD to address these typographical errors. <HD SOURCE="HD1">Request for Revised Corrective Action</HD> Delta requested an additional exception to address an error in a corrective procedure's steps and references. Delta requested that the erroneous procedure be replaced by a requirement for operators to contact the manufacturer for repair instructions. Delta explained that using the corrective action procedure as detailed in the service information referenced in Transport Canada AD CF-2023-58 would result in an unfilled countersink on the previous head side of the installation. Delta further explained that this is not a condition expected by the aircraft structural repair publication (ASRP) sections referenced for fastener installation. Delta said it contacted Airbus Canada for further information and was told there is no standard repair for that situation and it would need to be addressed on a case-by-case basis. The FAA acknowledges the commenter's concern and agrees that the commenter will have to contact the manufacturer to obtain instructions for their airplanes. However, the FAA does not consider it appropriate to include provisions in an AD applicable only to an individual airplane or configuration. Once this AD is published, any person may request approval of an alternative method of compliance (AMOC) under the provisions of paragraph (i)(1) of this AD. The FAA has not changed this AD in this regard. <HD SOURCE="HD1">Conclusion</HD> This product has been approved by the aviation authority of another country and is approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, it has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA reviewed the relevant data, considered the comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on this product. Except for minor editorial changes, and any other changes described previously, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> Transport Canada AD CF-2023-58 specifies procedures for a general visual inspection for positioning and sufficient clearance of Hi-Lite fasteners in certain fuselage and keel beam areas, an inspection for damage (includes rupturing, cracking, or denting) of the FIREX lines, and applicable corrective actions (including fastener replacement, changing the direction of the fastener, oversizing the fastener, and repair of the FIREX lines). 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">Costs of Compliance</HD> The FAA estimates that this AD will affect 50 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: <GPOTABLE COLS="4" OPTS="L2,nj,i1" CDEF="s100,10C,r30,xs90"> <TTITLE>Estimated Costs for Required Actions</TTITLE> <CHED H="1">Labor cost</CHED> <CHED H="1">Parts cost</CHED> <CHED H="1">Cost per product</CHED> <CHED H="1">Cost on U.S. operators</CHED> <ROW> <ENT I="01">Up to 33 work-ho ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 19k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━