Proposed Rule2026-00117
Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes
Primary source
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Published
January 7, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
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.
Full Text
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<title>Federal Register, Volume 91 Issue 4 (Wednesday, January 7, 2026)</title>
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[Federal Register Volume 91, Number 4 (Wednesday, January 7, 2026)]
[Proposed Rules]
[Pages 454-457]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-00117]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 91, No. 4 / Wednesday, January 7, 2026 /
Proposed Rules
[[Page 454]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-5402; Project Identifier MCAI-2025-00425-T]
RIN 2120-AA64
Airworthiness Directives; De Havilland Aircraft of Canada Limited
(Type Certificate Previously Held by Bombardier, Inc.) Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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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:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: 202-493-2251.
<bullet> 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.
<bullet> 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 <a href="http://regulations.gov">regulations.gov</a> 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:
<bullet> 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 <a href="/cdn-cgi/l/email-protection#e8bcabc6a9819a9f879a9c8081868d9b9bac819a8d8b9c819e8d9bc5ab87869b818f868d9b8c8d86899e818f898a8184819c8dc6bcaba89c8bc68f8bc68b89"><span class="__cf_email__" data-cfemail="792d3a5738100b0e160b0d1110171c0a0a3d100b1c1a0d100f1c0a543a16170a101e171c0a1d1c17180f101e181b1015100d1c572d3a390d1a571e1a571a18">[email protected]</span></a>. You may find this material on the
Transport Canada website at tc.canada.ca/en/aviation. It is also
available at <a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-2025-5402.
<bullet> 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: <a href="/cdn-cgi/l/email-protection#efd6c28e999cc281968e8c80c28c809caf898e8ec1888099"><span class="__cf_email__" data-cfemail="fcc5d19d8a8fd192859d9f93d19f938fbc9a9d9dd29b938a">[email protected]</span></a>.
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
<a href="http://regulations.gov">regulations.gov</a>, 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: <a href="/cdn-cgi/l/email-protection#764f5b1700055b180f1715195b1519053610171758111900"><span class="__cf_email__" data-cfemail="dee7f3bfa8adf3b0a7bfbdb1f3bdb1ad9eb8bfbff0b9b1a8">[email protected]</span></a>. 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.
[[Page 455]]
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 <a href="http://regulations.gov">regulations.gov</a> 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:
<bullet> 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).
<bullet> 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.
<bullet> 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
<a href="http://regulations.gov">regulations.gov</a> 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:
[[Page 456]]
Estimated Costs for Required Actions
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Labor cost Parts cost Cost per product Cost on U.S. operators
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Up to 81 work-hours x $85 per hour = Up to $14,233.......... Up to $21,118.......... Up to $1,140,372.
$6,885.
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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
0
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
0
2. The FAA amends Sec. 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
[[Page 457]]
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:
<a href="/cdn-cgi/l/email-protection#6f2e22202c2f090e0e41080019"><span class="__cf_email__" data-cfemail="a4e5e9ebe7e4c2c5c58ac3cbd2">[email protected]</span></a>. 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 <a href="/cdn-cgi/l/email-protection#794054180f0a541700181a16541a160a391f1818571e160f"><span class="__cf_email__" data-cfemail="8eb7a3eff8fda3e0f7efede1a3ede1fdcee8efefa0e9e1f8">[email protected]</span></a>.
(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 <a href="/cdn-cgi/l/email-protection#5e0a1d701f372c29312c2a3637303b2d2d1a372c3b3d2a37283b2d731d31302d3739303b2d3a3b303f2837393f3c3732372a3b700a1d1e2a3d70393d703d3f"><span class="__cf_email__" data-cfemail="d88c9bf699b1aaafb7aaacb0b1b6bdabab9cb1aabdbbacb1aebdabf59bb7b6abb1bfb6bdabbcbdb6b9aeb1bfb9bab1b4b1acbdf68c9b98acbbf6bfbbf6bbb9">[email protected]</span></a>. 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 <a href="http://www.archives.gov/federal-register/cfr/ibr-locations">www.archives.gov/federal-register/cfr/ibr-locations</a> or email <a href="/cdn-cgi/l/email-protection#492f3b6720273a392c2a3d2026270927283b28672e263f"><span class="__cf_email__" data-cfemail="ff998dd196918c8f9a9c8b969091bf919e8d9ed1989089">[email protected]</span></a>.
Issued on December 31, 2025.
Christopher R. Parker,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2026-00117 Filed 1-6-26; 8:45 am]
BILLING CODE 4910-13-P
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