Airworthiness Directives; Bombardier, Inc., Airplanes

<RULE> DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-0483; Project Identifier MCAI-2024-00523-T; Amendment 39-23182; AD 2025-22-04]</DEPDOC> <RIN>RIN 2120-AA64</RIN> <SUBJECT>Airworthiness Directives; 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 all Bombardier, Inc., Model CL-600-2B16 (604 Variant) airplanes. This AD was prompted by reports that the flap system on-board recorder (FSOBR) interfaces with the flap control unit signals and may result in the flap control unit monitors tripping, causing Flap Fail messages and possibly an uncommanded flap movement. This AD requires the disconnection of the FSOBR and prohibits future installation of this system. 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 December 23, 2025. The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of December 23, 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-2025-0483; 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 Bombardier material identified in this AD, contact Bombardier Business Aircraft Customer Response Center, 400 Côte-Vertu Road West, Dorval, Québec H4S 1Y9, Canada; telephone 514-855-2999; email <E T="03">ac.yul@aero.bombardier.com;</E> website <E T="03">bombardier.com</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-2025-0483. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Steven Dzierzynski, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 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 all Bombardier, Inc., Model CL-600-2B16 (604 Variant) airplanes. The NPRM was published in the <E T="04">Federal Register</E> on April 7, 2025 (90 FR 14929). The NPRM was prompted by AD CF-2024-31R1, dated December 17, 2024 (Transport Canada AD CF-2024-31R1) (also referred to as the MCAI), issued by Transport Canada, which is the aviation authority for Canada. The MCAI states that the FSOBR interfaces with the flap control unit Input/Output (I/O) signals and may result in the flap control unit monitors tripping, causing Flap Fail messages and possibly an uncommanded flap movement. This event combined with other flap system failures can lead to an uncommanded flap runaway. This condition, if not addressed, could lead to loss of control of the airplane. In the NPRM, the FAA proposed to require the disconnection of the FSOBR and prohibit future installation of this system. 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-2025-0483. <HD SOURCE="HD1">Discussion of Final Airworthiness Directive</HD> <HD SOURCE="HD1">Comments</HD> The FAA received comments from The Boeing Company (Boeing) and an anonymous commenter. The following presents the comments received on the NPRM and the FAA's response to each comment. <HD SOURCE="HD1">Request for Clarification on FSOBR Unit</HD> Boeing requested clarification on the state of the FSOBR unit. Boeing stated that paragraph (h) of the proposed AD conflicts with Bombardier Service Bulletin 650-27-005, dated May 20, 2024, because the service bulletin does not require the removal of FSOBR unit, part number (P/N) 604-70201-1. The FAA notes that this AD does not require removal of an affected FSOBR from the airplane. Instead, paragraph (g) of this AD requires disconnection of the FSOBR, which is consistent with the service bulletin instructions and other service bulletins referenced in table 1 to paragraph (g) of this AD. In addition, paragraph (h) of this AD prohibits installation of an affected FSOBR or FSOBR harness on or after the effective date of this AD, and reconnection of an FSOBR if one was installed on the airplane before the effective date of this AD. No change to the AD is necessary in this regard. <HD SOURCE="HD1">Request for Oversight of AD Compliance</HD> The anonymous commenter requested that the FAA require all affected aircraft operators to submit documentation of completed FSOBR disconnect, and mandate an independent verification process to ensure compliance, with public reporting of results for transparency. The FAA does not agree with the request. In certain cases, the FAA might determine that additional information ( <E T="03">i.e.,</E> data collection) is needed to understand the problem and develop appropriate mitigation for an unsafe condition. In this case, the unsafe condition was identified, and a corrective action was developed, without the need to require operator reports. However, an operator may still choose to send relevant information to the FAA. The FAA has not changed this AD in this regard. <HD SOURCE="HD1">Request To Track and Report Flap Control Incidents</HD> The anonymous commenter requested that the FAA collect and publicly release data on any post-AD incidents involving flap control systems on Bombardier, Inc., Model CL-600-2B16 (604 Variant) airplanes for at least five years, to track effectiveness and spot emerging risks. Under the bilateral agreement between Canada and the U.S., Transport Canada and the FAA have established implementation procedures specifying that the certificating authority is required to collect and analyze any data, and notify the other foreign authority of all known unsafe conditions and any necessary corrective actions. In this case, Transport Canada is the certificating authority for Bombardier aircraft. The FAA notes that U.S. operators may also submit any incidents to the service difficulty reporting (SDR) system at <E T="03">sdrs.faa.gov,</E> which is accessible to the public. No change to the AD is necessary in this regard. <HD SOURCE="HD1">Request To Require Root Cause Analysis and Collaboration</HD> The anonymous commenter requested that the FAA require manufacturers to conduct and publish root-cause analysis of FSOBR failures and collaborate with labor and consumer safety groups in designing future onboard systems to avoid similar risks. The FAA does not agree. As discussed in the previous comment, Transport Canada will continue to collect and analyze reports regarding the FSOBR system. The FAA has not revised the AD in this regard. <HD SOURCE="HD1">Request To Offset Economic Burden on Small Operators</HD> The anonymous commenter requested the FAA ensure that warranty coverage, reimbursement, or federal funding is accessible to offset compliance costs and prevent a disproportionate economic burden on smaller businesses or regional carriers. The FAA recognizes that this AD imposes certain operational costs on operators, and that operators have an obligation to maintain their airplanes in airworthy condition. However, the FAA does not mandate warranty coverage, reimbursement, or federal funding, and has not changed this AD in this regard. <HD SOURCE="HD1">Request To Provide Compliance Time Flexibility for Small Operators</HD> The anonymous commenter requested that the FAA provide targeted support or flexibility for compliance timelines to operators serving rural, low-income, or remote communities, ensuring continued access to Essential Air Services. The FAA does not agree. The compliance time for this AD was developed based on the recommendations of Transport Canada and the manufacturer, the urgency associated with the subject unsafe condition, and the practical aspect of accomplishing the required actions. The FAA has determined that the compliance time required by this AD will ensure an appropriate level of safety. The FAA has not changed this AD in this regard. <HD SOURCE="HD1">Request for Certified Personnel To Perform Work, With Whistleblower Protection</HD> The anonymous commenter requested that the FAA require only FAA-certified technicians to perform the FSOBR maintenance and disconnect procedures, with explicit whistleblower protections for reporting safety lapses or procedural shortcuts. The FAA notes that FAA regulations require maintenance, preventative maintenance, and alterations be performed by certified personnel (14 CFR 43.3 and 43.17). Further, the Wendell H. Ford Aviation Investment and Reform Act for the 21st Century (49 U.S.C. 42121) prohibits discrimination against employees of the U.S. air carrier industry and U.S. manufacturers who report information related to air carrier safety. More information about the FAA AIR-21 Whistleblower Protection Program is available at <E T="03">https://www.faa.gov/ab ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 22k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━