Rule

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

A Rule by the Federal Aviation Administration on 04/02/2026

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• Public Inspection Published Document: 2026-06465 (91 FR 16546) Document Headings ###### Department of Transportation

Federal Aviation Administration

1. 14 CFR Part 39
2. [Docket No. FAA-2026-3470; Project Identifier MCAI-2026-00210-T; Amendment 39-23302; AD 2026-07-07]
3. RIN 2120-AA64

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for all Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. This AD was prompted by the discovery that the outflow valve (OFV) direct current (DC) motor could potentially be inoperative when used in high differential pressure conditions. This AD prohibits dispatching an airplane under certain master minimum equipment list (MMEL) items and prohibits dispatching if a certain crew alerting system (CAS) message is displayed. The FAA is issuing this AD to address the unsafe condition on these products.

DATES:

This AD is effective April 17, 2026.

The FAA must receive comments on this AD by May 18, 2026.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments.
• Fax: 202-493-2251.
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2026-3470; 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 street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT:

Joshua Baek, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562-627-6725; email: joshua.y.baek@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written data, views, or arguments about this final rule. Send your comments using a method listed under the ADDRESSES section. Include “Docket No. FAA-2026-3470; Project Identifier MCAI-2026-00210-T” at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, 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 final rule 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 regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this final rule.

Confidential Business Information

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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Joshua Baek, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562-627-6725; email: joshua.y.baek@faa.gov. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Background

Transport Canada, which is the aviation authority for Canada, has issued Transport Canada AD CF-2026-10, dated February 27, 2026 (Transport Canada AD CF-2026-10) (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 it was discovered during production flight tests that the OFV DC motor could potentially be inoperative when used in high differential pressure conditions. The cabin pressure control system (CPCS) automatically controls the pressure inside the cabin by controlling the flow of pressurized air through the OFV. The OFV normally operates in automatic (AUTO) mode and uses two separate OFV stepper motors during all phases of flight. The OFV can also operate in manual (MAN) mode and use the OFV DC motor under certain condition. The high differential pressure across the OFV can increase the friction between the OFV butterfly shaft and the OFV body, resulting in excessive torque being required to operate the OFV. This excessive torque may trip the OFV MAN mode torque limiter resulting in loss of OFV control in CPCS MAN mode. This condition, if not corrected, could potentially lead to total loss of cabin pressure control, excessive differential pressure across the airplane structure, inability to rapidly depressurize the airplane to ambient, when needed, and inability to evacuate smoke, when needed.

The FAA is issuing this AD to address the unsafe condition on these products.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-3470.

FAA's Determination

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 is issuing this AD after determining that the unsafe condition described previously is ( printed page 16547) likely to exist or develop on other products of the same type design.

AD Requirements

This AD prohibits dispatching an airplane under certain dispatch provisions within Master Minimum Equipment List (MMEL) items 21-33-03 and 21-33-04 and prohibits dispatch if a certain CAS message is displayed.

The FAA notes there are two operational procedures (O) within MMEL items 21-33-03 and 21-33-04. For this AD, only the operational procedures listed in figure 1 to paragraph (g)(2) of this AD are prohibited.

Interim Action

The FAA considers that this AD is an interim action. If final action is later identified, the FAA might consider further rulemaking then.

Justification for Immediate Adoption and Determination of the Effective Date

Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq.) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for “good cause,” finds that those procedures are “impracticable, unnecessary, or contrary to the public interest.” Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause.

An unsafe condition exists that requires the immediate adoption of this AD without providing an opportunity for public comments prior to adoption. The FAA has found that the risk to the flying public justifies forgoing notice and comment prior to adoption of this rule because the OFV DC motor could potentially be inoperative when used in high differential pressure conditions. The high differential pressure across the OFV can increase the friction between the OFV butterfly shaft and the OFV body, resulting in excessive torque being required to operate the OFV. This excessive torque may trip the OFV MAN mode torque limiter resulting in loss of OFV control in CPCS MAN mode. This condition, if not corrected, could potentially lead to total loss of cabin pressure control, excessive differential pressure across the airplane structure, inability to rapidly depressurize the airplane to ambient, when needed, and inability to evacuate smoke, when needed. Additionally, the compliance time in this AD is shorter than the time necessary for the public to comment and for publication of the final rule. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b).

In addition, the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days, for the same reasons the FAA found good cause to forgo notice and comment.

Regulatory Flexibility Act

The requirements of the Regulatory Flexibility Act (RFA) do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without notice and comment, RFA analysis is not required.

Costs of Compliance

The FAA estimates that this AD affects 198 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:

| Labor cost | Parts cost | Cost per
product | Cost on U.S.
operators |
| --- | --- | --- | --- |
| 1 work-hour × $85 per hour = $85 | $0 | $85 | $16,830 |

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, and

(2) Will not affect intrastate aviation in Alaska.

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

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

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

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

2026-07-07 Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.): Amendment 39-23302; Docket No. FAA-2026-3470; Project Identifier MCAI-2026-00210-T.

(a) Effective Date

This airworthiness directive (AD) is effective April 17, 2026.

(b) Affected ADs

None. ( printed page 16548)

(c) Applicability

This AD applies to all Airbus Canada Limited Partnership (Type Certificate previously held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Model BD-500-1A10 and BD-500-1A11 airplanes, certificated in any category.

(d) Subject

Air Transport Association (ATA) of America Code 21, Air conditioning system.

(e) Unsafe Condition

This AD was prompted by the discovery during production flight tests that the outflow valve (OFV) direct current (DC) motor could potentially be inoperative when used in high differential pressure conditions. The FAA is issuing this AD to address loss of OFV control in cabin pressure control system (CPCS) manual (MAN) mode, which if not corrected, could potentially lead to total loss of cabin pressure control, excessive differential pressure across the airplane structure, inability to rapidly depressurize the airplane to ambient, when needed, and inability to evacuate smoke, when needed.

(f) Compliance

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

(g) Dispatch Prohibitions

(1) As of the effective date of this AD, no person may dispatch an airplane if crew alerting system (CAS) message “AUTO PRESS FAIL (CAUTION)” is displayed.

(2) As of the effective date of this AD, no person may dispatch an airplane under the operational procedures of the operator's minimum equipment list (MEL) items corresponding with the following operational procedures of the Master Minimum Equipment List (MMEL) items listed in figure 1 to paragraph (g)(2) of this AD.

Note 1 to paragraph (g)(2): There are two operational procedures (O) within MMEL items 21-33-03 and 21-33-04. For this AD, only dispatch under the operational procedures listed in figure 1 to paragraph (g)(2) of this AD is prohibited.

Figure 1 to Paragraph (g)(2)—Prohibited MMEL Items

| 21. Air Conditioning | | |
| Sequence No. | Item | Description |
| 33-03 | Landing Field Elevation (LFE) Indication | (O) May be inoperative provided:
(a) Pressurization is operated in manual control mode,
(b) Autopilot is operative, |
| | | (c) Minimum enroute altitude does not exceed 10,000 ft. above MSL, and |
| | | (d) Operations are restricted to airports at or below 8,000 ft. Landing Field Elevation (LFE). |
| 33-04 | Landing Field Elevation (LFE) Automatic Selection | (O) May be inoperative provided:
(a) Pressurization is conducted in manual mode,
(b) Autopilot is operative, and
(c) Operations are restricted to airports at or below 8,000 ft. Landing Field Elevation (LFE). |

(h) Additional AD Provisions

The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, AIR-520, Continued Operational Safety 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 Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (i) 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, AIR-520, Continued Operational Safety Branch, FAA; or Transport Canada; or Airbus Canada Limited Partnership's Transport Canada Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.

(i) Additional Information

For more information about this AD, contact Joshua Baek, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562-627-6725; email: joshua.y.baek@faa.gov.

(j) Material Incorporated by Reference

None.

Issued on March 31, 2026.

Victor Wicklund,

Acting Director, Integrated Certificate Management Division, Aircraft Certification Service.

[FR Doc. 2026-06465 Filed 3-31-26; 4:15 pm]

BILLING CODE 4910-13-P

Published Document: 2026-06465 (91 FR 16546)