# [Amended]
**AGENCY:**
Federal Aviation Administration (FAA), DOT.
**ACTION:**
Notice of proposed rulemaking (NPRM).
**SUMMARY:**
The FAA proposes to adopt a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. This proposed AD was prompted by multiple in-service reports of cracks in elevator power control unit (PCU) brackets (fittings) and the elevator front spar. This proposed AD would require replacing bushings and installing new washers on the elevator PCU arm fitting assembly, installing doublers at the front spar of the elevator structure assembly, replacing horizontal stabilizer rear spar elevator PCU fittings, and applicable on-conditions actions. 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 February 23, 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-2025-5402; 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 *[email protected]* . 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-2025-5402.
• 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:**
Yaser Osman, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone (516) 228 7300; email: *[email protected].*
**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-2025-5402; Project Identifier MCAI-2025-00425-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 Yaser Osman, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone (516) 228 7300; email: *[email protected].* 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-2025-19, dated March 24, 2025 (Transport Canada AD CF-2025-19) (also referred to as the MCAI), to correct an unsafe condition for certain De Havilland Aircraft of Canada Limited Model DHC-8-401, and -402 airplanes. The MCAI states there have been reports of multiple instances of in-service cracking in the elevator PCU brackets (fittings) located on the horizontal stabilizer rear spar, as well as four cases of cracking on the elevator front spar. In one case, the cracking progressed to the point where the PCU bracket detached. An investigation determined that the common contributing factor in all cases was force-fight loads generated during elevator movement by the PCUs. Potential root causes identified include elevator system mis-rigging, improper clamping of PCU brackets due to insufficient shimming, and misalignment of the horizontal stabilizer and elevator hinges during assembly.
The FAA is proposing this AD to address cracks in elevator PCU brackets (fittings) and the elevator front spar, which could result in failure of an elevator PCU bracket and lead to an elevator jam. The unsafe condition, if not addressed, could, if both elevators are affected, result in the loss of pitch control. You may examine the MCAI in the AD docket at *regulations.gov* under Docket No. FAA-2025-5402.
**Terminating Action Explanation for Related Transport Canada AD**
This NPRM would require the actions specified in Transport Canada AD CF-2025-19. Accomplishment of certain actions would then terminate inspections required by Transport Canada AD CF-2024-10, dated March 1, 2024, which corresponds to FAA AD 2025-19-05, Amendment 39-23145 (90 FR 46340, September 26, 2025) (AD 2025-19-05). Paragraph (j) of AD 2025-19-05 provides the terminating action that corresponds to the terminating action specified in paragraph C. of Part I and paragraph D. of Part II of Transport Canada AD CF-2025-19.
**Material Incorporated by Reference Under 1 CFR Part 51**
Transport Canada AD CF-2025-19 specifies the following procedures:
• Replacing bushings and installing new washers on the elevator PCU arm fitting assembly, which includes inspecting bushing holes in the arm fitting assembly for corrosion, scoring, and structural degradation ( *i.e.,* hole diameters are not within specified diameters).
• Installing doublers between ribs 12 and 13 and between ribs 13 and 14 at the front spar of the elevator structure assembly and applicable on-condition actions. The installation includes a detailed visual inspection of the elevator front spar caps and detailed inspection of the upper skin panel for damage ( *i.e.,* cracking or corrosion), a bolt hole eddy current inspection for cracking at certain fastener holes, a high frequency eddy current for radial cracking at bend radius of certain rib lightening holes, and an inspection of the pressure sensitive lightening tape on certain lightening holes for missing or torn tape. On-condition actions include contacting the DHC technical helpdesk for an approved repair, contacting DHC technical helpdesk for support, and replacing pressure sensitive lightening tape with new tape.
• Replacing horizontal stabilizer rear spar elevator PCU fittings, which includes an eddy current inspection, if fittings are removed, for cracking at all mating holes on the spar web assembly and the lower skin.
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 accomplishing the actions specified in Transport Canada AD CF-2025-19 described previously, except for any differences identified as exceptions in the regulatory text of this proposed AD. See “Differences Between This Proposed AD and the Referenced Material” for a discussion of the general differences included in this AD.
**Differences Between This Proposed AD and the Referenced Material**
The material referenced in Transport Canada AD CF-2025-19 specifies inspecting bushing holes in the arm fitting assembly for corrosion, scoring, and structural degradation; however, it does not specify corrective action if any corrosion, scoring, and structural degradation is found. Therefore, this proposed AD would require, if any corrosion, scoring, and structural degradation is found, doing a repair using a method approved by the Manager, International Validation Branch, FAA; or Transport Canada; or De Havilland Aircraft of Canada Limited's Transport Canada Design Approval Organization (DAO).
The material referenced in Transport Canada AD CF-2025-19 specifies replacing pressure sensitive lightening tape if required; however, it does not specify the conditions that would require replacement. Therefore, this proposed AD would require replacing the pressure sensitive lightening tape if tape is missing or torn.
The material referenced in Transport Canada AD CF-2025-19 specifies inspecting mating holes on the spar web assembly and the lower skin for cracking; however, it does not specify corrective action if any cracking is found. Therefore, this proposed AD would require, if any cracking is found, doing a repair using a method approved by the Manager, International Validation Branch, FAA; or Transport Canada; or De Havilland Aircraft of Canada Limited's Transport Canada DAO.
**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-2025-19 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with Transport Canada AD CF-2025-19 in its entirety 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-2025-19 for compliance will be available at *regulations.gov* under Docket No. FAA-2025-5402 after the FAA final rule is published.
**Costs of Compliance**
The FAA estimates that this AD, if adopted as proposed, would affect 54 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:
| Labor cost | Parts cost | Cost per product | Cost on U.S. operators |
| --- | --- | --- | --- |
| Up to 81 work-hours × $85 per hour = $6,885 | Up to $14,233 | Up to $21,118 | Up to $1,140,372. |
The FAA has received no definitive data on which to base the cost estimates for the on-condition actions specified in this proposed AD.
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.
**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 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
2. The FAA amends § 39.13 by adding the following new airworthiness directive:
*De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.):* Docket No. FAA-2025-5402; Project Identifier MCAI-2025-00425-T.
**(a) Comments Due Date**
The FAA must receive comments on this airworthiness directive (AD) by February 23, 2026.
**(b) Affected ADs**
None.
**(c) Applicability**
This AD applies to De Havilland Aircraft of Canada Limited (type certificate previously held by Bombardier, Inc.) Model DHC-8-401 and -402 airplanes, certificated in any category, as identified in Transport Canada AD CF-2025-19, dated March 24, 2025 (Transport Canada AD CF-2025-19).
**(d) Subject**
Air Transport Association (ATA) of America Code 55, Stabilizers.
**(e) Unsafe Condition**
This AD was prompted by multiple in-service reports of cracks found in the elevator power control unit (PCU) brackets (fittings) and the elevator front spar. The FAA is issuing this AD to address such cracks, which could result in failure of an elevator PCU bracket and lead to an elevator jam. The unsafe condition, if not addressed, could, if both elevators are affected, result in the loss of pitch control.
**(f) Compliance**
Comply with this AD within the compliance times specified, unless already done.
**(g) Requirements**
Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, Transport Canada AD CF-2025-19.
**(h) Exception to Transport Canada AD CF-2025-19**
(1) Where Transport Canada AD CF-2025-19 refers to its effective date, this AD requires using the effective date of this AD.
(2) Where Transport Canada AD CF-2025-19 refers to hours air time, this AD requires using flight hours.
(3) If, during any inspection required by paragraph (g) of this AD, any corrosion, scoring, or structural degradation of the bushing holes in arm fitting assembly is found, before further flight, repair using a method approved by the Manager, International Validation Branch, FAA; or Transport Canada; or De Havilland Aircraft of Canada Limited's Transport Canada Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.
(4) Where the material referenced in Transport Canada AD CF-2025-19 specifies contacting the DHC technical helpdesk for an approved repair or support, for this AD, a repair must be done before further flight using a method approved by the Manager, International Validation Branch, FAA; or Transport Canada; or De Havilland Aircraft of Canada Limited's Transport Canada DAO. If approved by the DAO, the approval must include the DAO-authorized signature.
(5) Where the material referenced in Transport Canada AD CF-2025-19 specifies replacing pressure sensitive lightening tape if required, for this AD, replace the pressure sensitive lightening tape before further flight if tape is missing or torn.
(6) If, during any inspection required by paragraph (g) of this AD, any cracking at any mating hole on the spar web assembly or the lower skin is found, before further flight, repair using a method approved by the Manager, International Validation Branch, FAA; or Transport Canada; or De Havilland Aircraft of Canada Limited's Transport Canada DAO. If approved by the DAO, the approval must include the DAO-authorized signature.
**(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: *[email protected]* . 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 De Havilland Aircraft of Canada Limited'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 Yaser Osman, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; email *[email protected].*
**(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) Transport Canada AD CF-2025-19, dated March 24, 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 *[email protected].* 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 *[email protected].*
Issued on December 31, 2025.
Christopher R. Parker,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.