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]</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>
Notice of proposed rulemaking (NPRM).
<SUM>
<HD SOURCE="HED">SUMMARY:</HD>
The FAA proposes to adopt a new airworthiness directive (AD) for all Bombardier, Inc., Model CL-600-2B16 (604 Variant) airplanes. This proposed 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 proposed AD would require the disconnection of the FSOBR and prohibit future installation of this system. 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 May 22, 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-2025-0483; 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 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 Bombardier material identified in this proposed 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.
<FURINF>
<HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD>
Steven Dzierzynski, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 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">Comments Invited</HD>
The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the
<E T="02">ADDRESSES</E>
section. Include “Docket No. FAA-2025-0483; Project Identifier MCAI-2024-00523-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 the 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 Steven Dzierzynski, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; email
<E T="03">9-avs-nyaco-cos@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>
Transport Canada, which is the aviation authority for Canada, has issued Transport Canada AD CF-2024-31R1, dated December 17, 2024 (Transport Canada AD CF-2024-31R1) (also referred to after this as the MCAI), to correct an unsafe condition on all Bombardier, Inc., Model CL-600-2B16 (604 Variant) airplanes. 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.
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-2025-0483.
<HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD>
The FAA reviewed Bombardier Service Bulletins 650-27-005, 605-27-012, and 604-27-041, all dated May 20, 2024. This material specifies procedures to disconnect the FSOBR. These documents are distinct since they apply to different airplane serial numbers. 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>
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 is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.
<HD SOURCE="HD1">Proposed AD Requirements in This NPRM</HD>
This proposed AD would require accomplishing the actions specified in the material already described. This proposed AD would also prohibit the installation of affected parts.
<HD SOURCE="HD1">Costs of Compliance</HD>
The FAA estimates that this AD, if adopted as proposed, would affect 442 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:
<GPOTABLE COLS="4" OPTS="L2,nj,i1" CDEF="s50,r50,r50,r50">
<TTITLE>Estimated Costs for Required Actions</TTITLE>
<CHED H="1">Labor cost</CHED>
<CHED H="1">Parts cost</CHED>
Cost on U.S.
operators
</CHED>
<ROW>
<ENT I="01">Up to 3 work-hours × $85 per hour = $255</ENT>
<ENT>Minimal</ENT>
<ENT>Up to $255</ENT>
<ENT>Up to $112,710</ENT>
</ROW>
</GPOTABLE>
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.
<HD SOURCE="HD1">Authority for This Rulemaking</HD>
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.
<HD SOURCE="HD1">Regulatory Findings</HD>
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 Fle
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