Airworthiness Directive for Bombardier Challenger Jets

Content

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for all Bombardier Inc. Model CL-600-1A11 (600), CL-600-2A12 (601),
and CL-600-2B16 (601-3A, 601-3R, and 604 Variants) airplanes. This AD was prompted by a report of uncommanded nose wheel steering
upon landing with touchdown on the runway centerline. This AD requires replacing the nosewheel steering rudder pedal potentiometer
universal coupling setscrews. This AD also requires revising the existing maintenance or inspection program, as applicable,
to incorporate new life limits for the setscrews. The FAA is issuing this AD to address the unsafe condition on these products.

DATES:

This AD is effective May 8, 2026.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as
of May 8, 2026.

ADDRESSES:

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2025-1732; 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.

Material Incorporated by Reference:

• 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 *ac.yul@aero.bombardier.com;* website *https://my.bombardier.com.*

• 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 regulations.gov under Docket No. FAA-2025-1732.

FOR FURTHER INFORMATION CONTACT:

John Massey, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; email 9-avs-nyaco-cos@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

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-600-1A11 (600), CL-600-2A12 (601), and CL-600-2B16 (601-3A, 601-3R, and 604 Variants) airplanes. The NPRM was
published in the
Federal Register
on August 12, 2025 (90 FR 38713). The NPRM was prompted by AD CF-2024-12R1, dated August 13, 2024 (Transport Canada AD CF-2024-12R1)
(also referred to as the MCAI), issued by Transport Canada, which is the aviation authority for Canada. The MCAI states that
there has been an in-service report where upon landing with touchdown on the runway centerline, following standard procedure,
the flight spoilers and thrust reverser were used after the nose wheel touchdown. As the airplane speed reduced to below 80
knots, the airplane veered to the left. The airplane was maintained on the runway by using the rudder and by differential
braking. Further investigation determined that the nosewheel steering rudder pedal potentiometer universal coupling setscrews
were loose, causing an uncommanded steering input.

In the NPRM, the FAA proposed to require replacing the nosewheel steering rudder pedal potentiometer universal coupling setscrews.
The FAA also proposed revising the existing maintenance or inspection program, as applicable, to incorporate new life limits
for the setscrews. The FAA is issuing this AD to address uncommanded nosewheel steering due to loose nosewheel steering rudder
pedal potentiometer universal coupling setscrews. The unsafe condition, if not addressed, could lead to a runway excursion.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-1732.

Discussion of Final Airworthiness Directive

Comments

The FAA received a comment from Bombardier. The following presents the comments received on the NPRM and the FAA's response
to each comment.

Request To Correct a Part Name

Bombardier requested the FAA correct the part name from “nose wheel steering potentiometer universal coupling” to “nose wheel
steering rudder pedal potentiometer universal coupling.” Bombardier suggested that this change would reduce confusion regarding
potentiometers.

The FAA agrees with the requested use of the term “nose wheel steering rudder pedal potentiometer universal coupling” throughout
the final rule. The FAA has revised this final rule accordingly.

Request To Revise References to Temporary Revisions (TR)

Bombardier requested the FAA revise the AD to change the TR reference numbers for the CL600 and CL601 Time Limits/Maintenance
Checks (TLMC) as follows:

• Replace CL600 TLMC TR 5-165 with TR 5-167.
• Replace CL601 TLMC TR 5-269 with TR 5-272.
• Replace CL601A TLMC TR 5-283 with TR 5-286. Bombardier noted that later revisions of the TRs specified in the proposed AD are now available.

The FAA agrees to clarify. Paragraph (h) of this AD requires operators to incorporate “the information in the applicable temporary
revision” of the specified TRs. If operators incorporate a later revision of a TR that contains the same information as the
specified TR revision, then they are in compliance with paragraph (h) of this AD. The FAA has reviewed the later revisions
of the TRs and determined that they do contain the same information. However, if there are changes to procedures in later
revisions, operators may request an alternative method of compliance with this AD under the provisions of paragraph (i)(1)
of this AD. The FAA has not revised this AD in response to this comment.

Conclusion

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 agreement with this State of Design Authority, that authority has notified
the FAA of the unsafe condition described in the MCAI referenced above. The FAA reviewed the relevant data, considered any
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 these products. 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.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed the following material issued by Bombardier:

• Bombardier Service Bulletin 600-0782, dated October 30, 2023.
• Bombardier Service Bulletin 601-1114, dated October 30, 2023.
• Bombardier Service Bulletin 604-32-033, dated October 30, 2023.
• Bombardier Service Bulletin 605-32-010, dated October 30, 2023.
• Bombardier Service Bulletin 650-32-007, dated October 30, 2023. This material contains procedures to replace the existing nosewheel steering rudder pedal potentiometer universal coupling setscrews with new self-locking setscrews, anaerobic retaining compound, and specified torque, and rig the potentiometer; and perform an operational test of the nosewheel steering system. These documents are distinct since they apply to different airplane models.

The FAA also reviewed the following Bombardier material:

• Bombardier Challenger 600 Time Limits/Maintenance Checks (TLMC) Temporary Revision (TR) No. TR 5-165, dated October 25, 2023.
• Bombardier Challenger 601 TLMC TR No. TR 5-269, dated October 25, 2023.
• Bombardier Challenger 601 TLMC TR No. TR 5-283, dated October 25, 2023.
• Bombardier Challenger 604 TLMC TR No. 5-2-73, dated October 25, 2023.
• Bombardier Challenger 605 TLMC TR No. 5-2-29, dated October 25, 2023.
• Bombardier Challenger 650 TLMC TR No. 5-2-5, dated October 16, 2023. This material specifies certain life limits of the safe life items. These documents are distinct since they apply to different airplane models.

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
ADDRESSES
section.

Costs of Compliance

The FAA estimates that this AD affects 930 airplanes of U.S. registry. The FAA estimates the following costs to comply with
this AD:

| Action | Labor cost | Parts cost | Cost per
product | Cost on U.S.
operators |
| --- | --- | --- | --- | --- |
| Setscrew replacement | 4 work-hours × $85 per hour = $340 | $40 | $380 | $353,400 |
The FAA has determined that revising the maintenance or inspection program takes an average of 90 work-hours per operator,
although the agency recognizes that this number may vary from operator to operator. Since operators incorporate maintenance
or inspection program changes for their affected fleet(s), the FAA has determined that a per-operator estimate is more accurate
than a per-airplane estimate. Therefore, the agency estimates the average total cost per operator to be $7,650 (90 work-hours
× $85 per work-hour).

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some or all of the costs
of this AD may be covered under warranty, thereby reducing the cost impact on affected operators.

Authority for This Rulemaking

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.

Regulatory Findings

This AD will not have federalism implications under Executive Order 13132. This AD will 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 that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Will not affect intrastate aviation in Alaska, and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the
criteria of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

The Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39—AIRWORTHINESS DIRECTIVES

Regulatory Text 1. The authority citation for part 39 continues to read as follows:

Authority:

49 U.S.C. 106(g), 40113, 44701.

§ 39.13 [Amended] Regulatory Text 2. The FAA amends § 39.13 by adding the following new airworthiness directive:

2026-07-01 Bombardier Inc.:
Amendment 39-23296; Docket No. FAA-2025-1732; Project Identifier MCAI-2024-00249-T.

(a) Effective Date

This airworthiness directive (AD) is effective May 8, 2026.

(b) Affected ADs

None.

(c) Applicability

This AD applies to all Bombardier Inc. airplanes, certificated in any category, identified in paragraphs (c)(1) through (3)
of this AD.

(1) Model CL-600-1A11 (600) airplanes.

(2) Model CL-600-2A12 (601) airplanes.

(3) Model CL-600-2B16 (601-3A, 601-3R, and 604 Variants) airplanes.

(d) Subject

Air Transport Association (ATA) of America Code 32, Landing gear.

(e) Unsafe Condition

This AD was prompted by a report of uncommanded nose wheel steering upon landing with touchdown on the runway centerline.
The FAA is issuing this AD to address uncommanded nosewheel steering due to loose nosewheel steering rudder pedal potentiometer
universal coupling setscrews. The unsafe condition, if not addressed, could lead to a runway excursion.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Replacement of Universal Coupling and Nosewheel Steering Rudder Pedal Potentiometer Universal Coupling Setscrews

For airplanes identified in paragraphs (g)(1) through (5) of this AD: Within 36 months or 1,400 flight hours, whichever occurs
first, after the effective date of this AD, replace the nosewheel steering rudder pedal potentiometer universal coupling setscrews
(self-locking setscrews) in accordance with Sections 2.B.(3) and 2.C. of the Accomplishment Instructions in the applicable
service bulletin identified in paragraphs (g)(1) through (5) of this AD.

(1) For Model CL-600-1A11 (600) airplanes, serial numbers 1004 through 1085 inclusive, on which the actions in Part E of Canadair
Challenger Service Bulletin 600-0380, Revision 02, have been completed: Bombardier Service Bulletin 600-0782, dated October
30, 2023.

Note 1 to paragraph (g)(1):
This note applies to paragraphs (g)(1) and (h)(1) of this AD. These airplanes are also referred to by the marketing designation
Challenger 600.

(2) For Model CL-600-2A12 (601) airplanes, serial numbers 3001 through 3059 inclusive, on which the actions in Part D of Canadair
Challenger Service Bulletin 601-0092, Revision 01 have been completed, and serial numbers 3060 through 3066 inclusive; and
Model CL-600-2B16 (601-3A and 601-3R Variants) airplanes, serial numbers 5001 through 5194 inclusive: Bombardier Service Bulletin
601-1114, dated October 30, 2023.

Note 2 to paragraph (g)(2):
This note applies to paragraphs (g)(2), (h)(2), and (h)(3) of this AD. These airplanes are also referred to by the marketing
designation Challenger 601.

(3) For Model CL-600-2B16 (604 Variant) airplanes, serial numbers 5301 through 5665 inclusive: Bombardier Service Bulletin
604-32-033, dated October 30, 2023.

Note 3 to paragraph (g)(3):
This note applies to paragraphs (g)(3) and (h)(4) of this

  AD. These airplanes are also referred to by the marketing designation Challenger 604.

(4) For Model CL-600-2B16 (604 Variant) airplanes, serial numbers 5701 through 5990 inclusive: Bombardier Service Bulletin
605-32-010, dated October 30, 2023.

Note 4 to paragraph (g)(4):
This note applies to paragraphs (g)(4) and (h)(5) of this AD. These airplanes are also referred to by the marketing designation
Challenger 605.

(5) For Model CL-600-2B16 (604 Variant) airplanes, serial numbers 6050 through 6193 inclusive: Bombardier Service Bulletin
650-32-007, dated October 30, 2023.

Note 5 to paragraph (g)(5):
This note applies to paragraphs (g)(5) and (h)(6) of this AD. These airplanes are also referred to by the marketing designation
Challenger 650.

(h) Maintenance/Inspection Program Revision

Within 60 days after the effective date of this AD, revise the existing maintenance or inspection program, as applicable,
to incorporate the information in the applicable temporary revision identified in paragraphs (h)(1) through (6) of this AD.
The initial compliance time for the replacement is within 96 months after the replacement required by paragraph (g) of this
AD. Using a different document with information identical to the information in the applicable temporary revision identified
in paragraphs (h)(1) through (6) of this AD is acceptable for compliance with the requirements of this paragraph.

(1) For all Model CL-600-1A11 (600) airplanes: Bombardier Challenger 600 Time Limits/Maintenance Checks (TLMC) Temporary Revision
(TR) No. TR 5-165, dated October 25, 2023.

(2) For all Model CL-600-2A12 (601) airplanes: Bombardier Challenger 601 TLMC TR No. TR 5-269, dated October 25, 2023.

(3) For all Model CL-600-2B16 airplanes (601-3A and 601-3R Variants): Bombardier Challenger 601 TLMC TR No. TR 5-283, dated
October 25, 2023.

(4) For Model CL-600-2B16 (604 Variant) airplanes, serial numbers 5301 through 5665 inclusive: Bombardier Challenger 604 TLMC
TR No. 5-2-73, dated October 25, 2023.

(5) For Model CL-600-2B16 (604 Variant) airplanes, serial numbers 5701 through 5990 inclusive: Bombardier Challenger 605 TLMC
TR No. 5-2-29, dated October 25, 2023.

(6) For Model CL-600-2B16 (604 Variant) airplanes, serial numbers 6050 and subsequent: Bombardier Challenger 650 TLMC TR No.
5-2-5, dated October 16, 2023.

(i) Additional AD Provisions

The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, International Validation Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the
procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or responsible
Flight Standards Office, as appropriate. If sending information directly to the manager of the International Validation Branch,
send it to the attention of the person identified in paragraph (j) of this AD and email to: AMOC@faa.gov. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager
of the responsible Flight Standards Office.

(2) Contacting the Manufacturer: For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method
approved by the Manager, International Validation Branch, FAA; or Transport Canada; or Bombardier's Transport Canada Design
Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.

(j) Additional Information

For more information about this AD, contact John Massey, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury,
NY 11590; telephone 516-228-7300; email 9-avs-nyaco-cos@faa.gov.

(k) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference of the material listed in this paragraph
under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this material as applicable to do the actions required by this AD, unless this AD specifies otherwise.

(i) Bombardier Challenger 600 Time Limits/Maintenance Checks (TLMC) Temporary Revision (TR) No. TR 5-165, dated October 25,
2023.

(ii) Bombardier Challenger 601 TLMC TR No. TR 5-269, dated October 25, 2023.

(iii) Bombardier Challenger 601 TLMC TR No. TR 5-283, dated October 25, 2023.

(iv) Bombardier Challenger 604 TLMC TR No. 5-2-73, dated October 25, 2023.

(v) Bombardier Challenger 605 TLMC TR No. 5-2-29, dated October 25, 2023.

(vi) Bombardier Challenger 650 TLMC TR No. 5-2-5, dated October 16, 2023.

(vii) Bombardier Service Bulletin 600-0782, dated October 30, 2023.

(viii) Bombardier Service Bulletin 601-1114, dated October 30, 2023.

(ix) Bombardier Service Bulletin 604-32-033, dated October 30, 2023.

(x) Bombardier Service Bulletin 605-32-010, dated October 30, 2023.

(xi) Bombardier Service Bulletin 650-32-007, dated October 30, 2023.

(3) 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 ac.yul@aero.bombardier.com; website https://my.bombardier.com.

(4) 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.

(5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email fr.inspection@nara.gov.

Issued on March 24, 2026. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2026-06506 Filed 4-2-26; 8:45 am] BILLING CODE 4910-13-P

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