[Federal Register Volume 90, Number 186 (Monday, September 29, 2025)]
[Proposed Rules]
[Pages 46538-46541]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-18805]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-2558; Project Identifier MCAI-2021-00022-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 all De Havilland Aircraft of Canada Limited Model DHC-8 airplanes.
This proposed AD was prompted by reports of cracked barrel nuts at the
wing front spar and horizontal stabilizer to vertical stabilizer joint.
This proposed AD would require repetitive inspections for cracking and
corrosion of the affected barrel nuts and applicable corrective
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 November
13, 2025.
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-2025-2558; 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 De Havilland Aircraft of Canada Limited material
identified in this proposed AD, contact De Havilland Aircraft of Canada
Limited, Dash 8 Series Customer Response Centre, 5800 Explorer Drive,
Mississauga, Ontario, L4W 5K9, Canada; telephone North America (toll-
free): 855-310-1013, Direct: 647-277-5820; email dehavilland.com">thd@dehavilland.com;
website dehavilland.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.
FOR FURTHER INFORMATION CONTACT: Christopher Spencer, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
phone: (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-2025-2558;
Project Identifier MCAI-2021-00022-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 the 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
[[Page 46539]]
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 Christopher Spencer, Aviation Safety Engineer, FAA, 1600
Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (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-2020-06R1, dated January 7, 2021
(Transport Canada AD CF-2020-06R1) (also referred to as the MCAI), to
correct an unsafe condition for all De Havilland Aircraft of Canada
Limited Model DHC-8-100 series airplanes; Model DHC-8-200 series
airplanes; Model DHC-8-300 series airplanes (which includes Model DHC-
8-314 airplanes); and Model DHC-8-400 series airplanes. Model DHC-8-314
airplanes are not certificated by the FAA and are not included on the
U.S. type certificate data sheet; this proposed AD therefore does not
include those airplanes in the applicability. The MCAI states there
were findings related to cracked barrel nuts at the wing front spar and
horizontal stabilizer to vertical stabilizer joint. For those
locations, Transport Canada issued AD CF-2011-24R1 (which corresponds
to FAA AD 2019-20-09, Amendment 39-19762 (84 FR 56680, October 23,
2019)) and AD CF-2015-13R1 (which corresponds to FAA AD 2018-22-03,
Amendment 39-19476 (83 FR 53563, October 24, 2018)) to address the
unsafe condition. Barrel nuts are also installed in other locations on
the airplane. An investigation determined that the cracking is caused
by corrosion from inadequate cadmium plating on the barrel nuts. This
condition, if not addressed, could result in failed barrel nuts that
could compromise the structural integrity of the affected joints (i.e.,
of the airplane) and could lead to loss of control of the airplane.
The FAA is proposing 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-2025-2558.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed De Havilland Aircraft of Canada Limited Service
Bulletin 8-05-11, dated April 29, 2022. This material specifies
procedures for detailed inspections for cracks and corrosion of the
barrel nuts at the flight compartment windshield side posts, the nose
landing gear trunnion plate assemblies, nacelle lower longeron
attachments, the front, mid and rear spar horizontal stabilizer to
vertical stabilizer attachments, the bathtub fittings attachments, the
wing rib YW23.858 assemblies, and at the wing rib YW42.00 assemblies,
and applicable corrective actions (e.g., repairs or replacement).
The FAA also reviewed De Havilland Aircraft of Canada Limited
Service Bulletin 84-27-73, dated May 8, 2019; and De Havilland Aircraft
of Canada Limited Service Bulletin 8-27-121, dated July 30, 2019. This
material specifies procedures, for a detailed inspection for cracks and
corrosion of the barrel nuts, having part number (P/N) DSC228-4, at the
rudder pedal adjustment mechanism, and applicable corrective actions
(i.e., replacement of barrel nuts, having P/N DSC228-4, with barrel
nuts, having P/N B0203073-4). These documents are distinct since they
apply to different airplane models.
The FAA also reviewed De Havilland Aircraft of Canada Limited
Service Bulletin 8-27-122, dated July 18, 2019. This material specifies
procedures for a detailed inspection for cracks and corrosion of the
barrel nuts, having P/N DSC228-5, at the control attachment fittings,
and applicable corrective actions (i.e., replacement of barrel nuts,
having P/N DSC228-5 with barrel nuts, having P/N B0203073-5).
The FAA also reviewed De Havilland Aircraft of Canada Limited
Service Bulletin 84-05-02, dated April 29, 2022. This material
specifies procedures for detailed inspections for cracks and corrosion
of the barrel nuts at the flight compartment windshield side posts, the
vertical stabilizer pitch feel trim frame, the front and rear spar wing
to fuselage attachment joint struts and fittings, and the bathtub
fitting attachments, and applicable corrective actions (e.g., repairs
or replacement).
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 and material referenced above. The FAA is issuing
this NPRM after determining that the unsafe condition described
previously is likely to exist or develop on other products of the same
type design.
Proposed AD Requirements in This NPRM
This proposed AD would require accomplishing the actions specified
in the material already described, except as discussed under
``Differences Between This Proposed AD and the MCAI or Referenced
Material.''
Differences Between This Proposed AD and the MCAI or Referenced
Material
Transport Canada AD CF-2020-06R1 introduces new maintenance review
board report (MRBR) intervals that the FAA cannot mandate as MRBRs as
specified in the MCAI. Instead of mandating the MRBR tasks as done in
the Transport Canada AD, the FAA, after coordination with Transport
Canada, determined the procedures specified in the service information
in paragraphs (g) and (h) of this proposed AD will be used because
those procedures refer to the corresponding airplane maintenance manual
(AMM) task numbers of the MRBR tasks. Therefore, the FAA proposes to
mandate the procedures as specified in the service information in
paragraphs (g) and (h) of this proposed AD.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 111 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:
[[Page 46540]]
Estimated Costs for Required Actions
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Cost per Cost on U.S.
Labor cost Parts cost product operators
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Up to 13 work-hours x $85 per hour = $680.......................... $0 $1,105 $122,655
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The FAA estimates the following costs to do any necessary on-
condition actions that would be required based on the results of any
required actions. The FAA has no way of determining the number of
aircraft that might need these on-condition actions:
Estimated Costs of On-Condition Actions
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Labor cost Parts cost Cost per product
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Up to 8 work-hours x $85 per hour = $0 * $680 *
$680................................
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* The FAA has received no definitive data on which to base the cost
estimates for the parts specified in this proposed AD.
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-2025-2558; Project
Identifier MCAI-2021-00022-T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by November 13, 2025.
(b) Affected ADs
None.
(c) Applicability
This AD applies to all De Havilland Aircraft of Canada Limited
airplanes, certificated in any category, identified in paragraphs
(c)(1) through (4) of this AD.
(1) Model DHC-8-101, -102, -103, and -106 airplanes.
(2) Model DHC-8-201 and -202 airplanes.
(3) Model DHC-8-301, -311, and -315 airplanes.
(4) Model DHC-8-400, -401 and -402 airplanes.
(d) Subject
Air Transport Association (ATA) of America Code 14, Hardware;
51, Standard practices/structures.
(e) Unsafe Condition
This AD was prompted by reports of cracked barrel nuts at the
wing front spar and horizontal stabilizer to vertical stabilizer
joint, which was caused by corrosion from inadequate cadmium plating
on the barrel nuts. The FAA is issuing this AD to address cracking
and corrosion of the affected barrel nuts. The unsafe condition, if
not addressed, could result in failed barrel nuts that could
compromise the structural integrity of the airplane and could lead
to loss of control of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Actions for Model DHC-8-100, -200, and -300 Series Airplanes
For Model DHC-8-101, -102, -103, and -106 airplanes, Model DHC-
8-201 and -202 airplanes, and Model DHC-8-301, -311, and -315
airplanes: Do the actions specified in paragraphs (g)(1) through (4)
of this AD.
(1) As of 60 days after the effective date of this AD: At the
next flight compartment windshield replacement, do a detailed
inspection for cracks and corrosion of the barrel nuts at the
windshield side posts and, before further flight, do all applicable
corrective actions, in accordance with the Accomplishment
Instructions of De Havilland Aircraft of Canada Limited Service
Bulletin 8-05-11, dated April 29, 2022. Repeat the inspection
thereafter at each flight compartment windshield replacement.
(2) Within 6 years since entry into service, or within 60 days
after the effective date of this AD, whichever occurs later, do
detailed inspections for cracks and corrosion of the barrel nuts at
the nose landing gear trunnion plate assemblies, nacelle lower
longeron attachments, the front, mid and rear spar horizontal
stabilizer to vertical stabilizer attachments, the bathtub fittings
attachments, the wing rib YW23.858 assemblies, and the wing rib
YW42.00 assemblies, and before further flight, do all applicable
corrective
[[Page 46541]]
actions, in accordance with the Accomplishment Instructions of De
Havilland Aircraft of Canada Limited Service Bulletin 8-05-11, dated
April 29, 2022. Repeat the inspection thereafter at intervals not to
exceed 6 years.
(3) Within 6 years since entry into service, or within 60 days
after the effective date of this AD, whichever occurs later, do a
detailed inspection for cracks and corrosion of the barrel nuts,
having part number (P/N) DSC228-5, at the control attachment
fittings, and before further flight, do all applicable corrective
actions, in accordance with the Accomplishment Instructions of De
Havilland Aircraft of Canada Limited Service Bulletin 8-27-122,
dated July 18, 2019. Repeat the inspection thereafter at intervals
not to exceed 6 years.
(4) Within 7 years since entry into service, or within 60 days
after the effective date of this AD, whichever occurs later, do a
detailed inspection for cracks and corrosion of the barrel nuts,
having P/N DSC228-4, at the rudder pedal adjustment mechanism, and
before further flight, do all applicable corrective actions, in
accordance with the Accomplishment Instructions of De Havilland
Aircraft of Canada Limited Service Bulletin 8-27-121, dated July 30,
2019. Repeat the inspection thereafter at intervals not to exceed 7
years.
(h) Actions for Model DHC-8-400 Series Airplanes
For Model DHC-8-400, -401 and -402 airplanes: Do the actions
specified in paragraphs (h)(1) through (3) of this AD.
(1) As of 60 days after the effective date of this AD: At the
next flight compartment windshield replacement, do a detailed
inspection for cracks and corrosion of the barrel nuts at the flight
compartment windshield side posts, and before further flight, do all
applicable corrective actions, in accordance with the Accomplishment
Instructions of De Havilland Aircraft of Canada Limited Service
Bulletin 84-05-02, dated April 29, 2022. Repeat the inspection
thereafter at each flight compartment windshield replacement.
(2) Within 6 years since entry into service, or within 60 days
after the effective date of this AD, whichever occurs later, do
detailed inspections for cracks and corrosion of the barrel nuts at
the vertical stabilizer pitch feel trim frame, the front and rear
spar wing to fuselage attachment joint struts and fittings, and the
bathtub fitting attachments, and before further flight, do all
applicable corrective actions, in accordance with the Accomplishment
Instructions of De Havilland Aircraft of Canada Limited Service
Bulletin 84-05-02, dated April 29, 2022. Repeat the inspections
thereafter at intervals not to exceed 6 years.
(3) Within 7 years since entry into service, or within 60 days
after the effective date of this AD, whichever occurs later, do a
detailed inspection for cracks and corrosion of the barrel nuts,
having P/N DSC228-4, at the rudder pedal adjustment mechanism, and
before further flight, do all applicable corrective actions, in
accordance with the Accomplishment Instructions of De Havilland
Aircraft of Canada Limited Service Bulletin 84-27-73, dated May 8,
2019. Repeat the inspection thereafter at intervals not to exceed 7
years.
(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 Christopher Spencer,
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; phone: (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) De Havilland Aircraft of Canada Limited Service Bulletin 8-
05-11, dated April 29, 2022.
(ii) De Havilland Aircraft of Canada Limited Service Bulletin 8-
27-121, dated July 30, 2019.
(iii) De Havilland Aircraft of Canada Limited Service Bulletin
8-27-122, dated July 18, 2019.
(iv) De Havilland Aircraft of Canada Limited Service Bulletin
84-05-02, dated April 29, 2022.
(v) De Havilland Aircraft of Canada Limited Service Bulletin 84-
27-73, dated May 8, 2019.
(3) For De Havilland Aircraft of Canada Limited material
identified in this AD, contact De Havilland Aircraft of Canada
Limited, Dash 8 Series Customer Response Centre, 5800 Explorer
Drive, Mississauga, Ontario, L4W 5K9, Canada; telephone North
America (toll-free): 855-310-1013, Direct: 647-277-5820; email
dehavilland.com">thd@dehavilland.com; website dehavilland.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 [email protected].
Issued on September 24, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2025-18805 Filed 9-26-25; 8:45 am]
BILLING CODE 4910-13-P