FAA Proposed Airworthiness Directive for MHI RJ Aviation Airplanes

Content

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all MHI RJ Aviation ULC Model CL-600-2C10 (Regional Jet Series
700, 701 & 702), CL-600-2C11 (Regional Jet Series 550), CL-600-2D15 (Regional Jet Series 705), and CL-600-2D24 (Regional Jet
Series 900) airplanes. This proposed AD was prompted by a determination that new or more restrictive airworthiness limitations
are necessary. This proposed AD would require revising the existing maintenance or inspection program, as applicable, to incorporate
new or more restrictive airworthiness limitations. The FAA is proposing this AD to address the unsafe condition on these products.

DATES:

The FAA must receive comments on this proposed AD by May 1, 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-2026-2714; 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.

Material Incorporated by Reference:

• For Transport Canada material identified in this proposed AD, contact Transport Canada, Transport Canada National Aircraft
Certification, 159 Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada; telephone 888-663-3639; email TC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca. You may find this material on the Transport Canada website at tc.canada.ca/en/aviation. It is also available at regulations.gov under Docket No. FAA-2026-2714.

• 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.

FOR FURTHER INFORMATION CONTACT:

Isabel Saltzman, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 516-228-7300; email: 9-avs-nyaco-cos@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments using a
method listed under the
ADDRESSES
section. Include “Docket No. FAA-2026-2714; Project Identifier MCAI-2025-00827-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 this 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 regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact
received about this NPRM.

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
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
Isabel Saltzman, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 516-228-7300; email: 9-avs-nyaco-cos@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-2025-26, dated May 6, 2025
(Transport Canada AD CF-2025-26) (also referred to as the MCAI), to correct an unsafe condition for all MHI RJ Aviation ULC
(Type Certificate previously held by Bombardier, Inc.) Model CL-600-2C10 (Regional Jet Series 700, 701 & 702), CL-600-2C11
(Regional Jet Series 550), CL-600-2D15 (Regional Jet Series 705), and CL-600-2D24 (Regional Jet Series 900) airplanes. The
MCAI states that new or more restrictive airworthiness limitations have been developed. The manufacturer introduced changes
to four airworthiness limitation items (ALIs) and added four new ALIs to Maintenance Requirements Manual (MRM) CSP B-053,
Part 2, Section 2, “Structural Inspections,” and Section 3, “Safe Life Components,” Revision 28,

  dated June 25, 2024. These changes are the result of the latest damage tolerance analyses that revealed the need for more
  restrictive inspections than initially assumed.

The FAA is proposing this AD to address new or more restrictive structural inspections and safe life limits. The unsafe condition,
if not addressed, could result in the loss of structural integrity of the airplane.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-2714.

Other Related Rulemaking

The FAA issued AD 2025-25-03, Amendment 39-23211 (90 FR 57680, December 12, 2025) (AD 2025-25-03), which applies to all MHI
RJ Aviation ULC Model CL-600-2C10 (Regional Jet Series 700, 701 & 702), CL-600-2C11 (Regional Jet Series 550), CL-600-2D15
(Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900), and CL-600-2E25 (Regional Jet Series 1000) airplanes. AD
2025-25-03 requires revising the existing maintenance or inspection program, as applicable, to incorporate new or more restrictive
airworthiness limitations. Accomplishing the actions in this proposed AD would terminate the corresponding requirements of
AD 2025-25-03 for the tasks identified in the material referenced in Transport Canada AD CF-2025-26 only.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed Transport Canada AD CF-2025-26, which specifies new or more restrictive airworthiness limitations for airplane
structures and safe life limits. 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.

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 NPRM after determining that
the unsafe condition described previously is likely to exist or develop in other products of the same type design.

Proposed AD Requirements in This NPRM

This proposed AD would require revising the existing maintenance or inspection program, as applicable, to incorporate new
or more restrictive airworthiness limitations, which are specified in Transport Canada AD CF-2025-26 described previously,
as incorporated by reference. Any differences with Transport Canada AD CF-2025-26 are identified as exceptions in the regulatory
text of this proposed AD.

This proposed AD would require revisions to certain operator maintenance documents to include new actions (e.g., inspections). Compliance with these actions is required by 14 CFR 91.403(c). For airplanes that have been previously modified,
altered, or repaired in the areas addressed by this proposed AD, the operator may not be able to accomplish the actions described
in the revisions. In this situation, to comply with 14 CFR 91.403(c), the operator must request approval for an alternative
method of compliance (AMOC) according to paragraph (k)(1) of this proposed AD.

Explanation of Required Compliance Information

In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation
authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA
has been coordinating this process with manufacturers and CAAs. As a result, the FAA proposes to incorporate Transport Canada
AD CF-2025-26 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with Transport Canada
AD CF-2025-26 through that incorporation, except for any differences identified as exceptions in the regulatory text of this
proposed AD. Material required by Transport Canada AD CF-2025-26 for compliance will be available at regulations.gov by searching for and locating Docket No. FAA-2026-2714 after the FAA final rule is published.

Airworthiness Limitation ADs Using the New Process

The FAA's process of incorporating by reference MCAI ADs as the primary source of information for compliance with corresponding
FAA ADs has been limited to certain MCAI ADs (primarily those with service bulletins as the primary source of information
for accomplishing the actions required by the FAA AD). However, the FAA is now expanding the process to include MCAI ADs that
require a change to airworthiness limitation documents, such as airworthiness limitation sections.

For these ADs that incorporate by reference an MCAI AD that changes airworthiness limitations, the FAA requirements are unchanged.
Operators must revise the existing maintenance or inspection program, as applicable, to incorporate the information specified
in the new airworthiness limitation document. The airworthiness limitations must be followed according to 14 CFR 91.403(c)
and 91.409(e).

The previous format of the airworthiness limitation ADs included a paragraph that specified that no alternative actions (e.g., inspections) or intervals may be used unless the actions and intervals are approved as an AMOC in accordance with the procedures
specified in the AMOC paragraph under “Additional AD Provisions.” This new format includes a “Provisions for Alternative Actions
and Intervals” paragraph that does not specifically refer to AMOCs, but operators may still request an AMOC to use an alternative
action or interval.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 589 airplanes of U.S. registry. The FAA estimates the
following costs to comply with this proposed AD:

The FAA has determined that revising the existing 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).

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

The FAA has 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 Flexibility Act.

List of Subjects in 14 CFR Part 39

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

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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:

MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier, Inc.):
Docket No. FAA-2026-2714; Project Identifier MCAI-2025-00827-T.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by May 1, 2026.

(b) Affected ADs

This AD affects AD 2025-25-03, Amendment 39-23211 (90 FR 57680, December 12, 2025) (AD 2025-25-03).

(c) Applicability

This AD applies to all MHI RJ Aviation ULC (Type Certificate previously held by Bombardier, Inc.) airplanes identified in
paragraphs (c)(1) through (4) of this AD, certificated in any category.

(1) Model CL-600-2C10 (Regional Jet Series 700, 701 & 702) airplanes.

(2) Model CL-600-2C11 (Regional Jet Series 550) airplanes.

(3) Model CL-600-2D15 (Regional Jet Series 705) airplanes.

(4) Model CL-600-2D24 (Regional Jet Series 900) airplanes.

(d) Subject

Air Transport Association (ATA) of America Code 05, Time Limits/Maintenance Checks.

(e) Unsafe Condition

This AD was prompted by a determination that new or more restrictive airworthiness limitations are necessary. The FAA is issuing
this AD to address new or more restrictive structural inspections and safe life limits. The unsafe condition, if not addressed,
could result in the loss of structural integrity of the airplane.

(f) Compliance

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

(g) Requirements

Within 30 days after the effective date of this AD: Comply with all required actions specified in, and in accordance with,
Transport Canada AD CF-2025-26, dated May 6, 2025 (Transport Canada AD CF-2025-26), except as specified in paragraph (h) of
this AD.

(h) Exception to Transport Canada AD CF-2025-26

(1) Where the “Corrective Actions” section of Transport Canada AD CF-2025-26 specifies to “Within the thresholds and repeat
intervals identified within the tasks, or discard time, as applicable, complete the new or more restrictive limitations contained
in the ALI sections of the MHIRJ MRM Part 2 publication identified in Table 1 below, as applicable to the aeroplane model
and configuration.”, this AD requires replacing that text with “Revise the existing maintenance or inspection program, as
applicable, by incorporating the new and revised ALI tasks identified in Table 1 of Transport Canada AD CF-2025-26.”

(2) The initial compliance time for doing the tasks specified in Table 1 of Transport Canada AD CF-2025-26 is at the applicable
threshold and discard time as specified in the material referenced in Transport Canada AD CF-2025-26, or within 30 days after
the effective date of this AD, whichever occurs later.

(i) Provisions for Alternative Actions and Intervals

After the existing maintenance or inspection program has been revised as required by paragraph (g) of this AD, no alternative
actions (e.g., inspections) and intervals are allowed unless they are approved as specified in the provisions of the “Corrective Actions”
section of Transport Canada AD CF-2025-26.

(j) Terminating Action for Certain Tasks Required by AD 2025-25-03

Accomplishing the actions required by this AD terminates the corresponding requirements of AD 2025-25-03 for the tasks identified
in the material referenced in Transport Canada AD CF-2025-26 only.

(k) 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 (l) 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 MHI RJ Aviation ULC's Transport Canada
Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.

(l) Additional Information

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

(m) 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) Transport Canada AD CF-2025-26, dated May 6, 2025.

(ii) [Reserved]

(3) 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 TC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca. You may find this material on the Transport Canada website at tc.canada.ca/en/aviation.

(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 12, 2026. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2026-05224 Filed 3-16-26; 8:45 am] BILLING CODE 4910-13-P

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