[Federal Register Volume 90, Number 117 (Friday, June 20, 2025)]
[Proposed Rules]
[Pages 26228-26231]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-11327]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-1107; Project Identifier MCAI-2024-00784-A]
RIN 2120-AA64
Airworthiness Directives; Viking Air Limited (Type Certificate
Previously Held by Bombardier Inc. and de Havilland, Inc.) Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2022-23-08, which applies to all Viking Air Limited (Viking) Model DHC-
3 airplanes. AD 2022-23-08 requires a visual inspection of the
stabilizer actuator to confirm that the stabilizer
[[Page 26229]]
actuator lock ring is present, correctly seated in the groove in the
upper housing, and engaged in the clamp nut, applicable corrective
actions, application of a torque seal, and sending the inspection
results to the FAA. This proposed AD would require repetitively
inspecting the stabilizer actuator to confirm that the stabilizer
actuator lock ring is present, correctly seated in the groove in the
upper housing, and engaged in the clamp nut; taking applicable
corrective actions; applying a witness mark (torque seal); and
installing a secondary retention feature as terminating action for the
repetitive inspections. This proposed AD would also prohibit the
installation of any stabilizer actuator unless it is a serviceable
part. The FAA is proposing this AD to address the unsafe condition on
these products.
DATES: The FAA must receive comments on this NPRM by August 4, 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-2025-1107; 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;
phone: (888) 663-3639; email: [email protected]; website: tc.canada.ca/en/aviation.
You may view this material at the FAA, Airworthiness
Products Section, Operational Safety Branch, 901 Locust, Kansas City,
MO 64106. For information on the availability of this material at the
FAA, call (817) 222-5110.
FOR FURTHER INFORMATION CONTACT: Brenda Buitrago, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
phone: (516) 228-7368; 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 to an address listed
under ADDRESSES. Include ``Docket No. FAA-2025-1107; Project Identifier
MCAI-2024-00784-A'' 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 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
Brenda Buitrago, Aviation Safety Engineer, FAA, 1600 Stewart Avenue,
Suite 410, Westbury, NY 11590. Any commentary that the FAA receives
which is not specifically designated as CBI will be placed in the
public docket for this rulemaking.
Background
The FAA issued AD 2022-23-08, Amendment 39-22235 (87 FR 66084,
November 2, 2022) (AD 2022-23-08), for Viking Model DHC-3 airplanes,
all serial numbers, certificated in any category. The FAA issued AD
2022-23-08 to correct an unsafe condition identified as a missing
stabilizer actuator lock ring.
AD 2022-23-08 requires a visual inspection of the stabilizer
actuator to confirm that the stabilizer actuator lock ring is present,
correctly seated in the groove in the upper housing, and engaged in the
clamp nut, applicable corrective actions, application of a torque seal,
and sending the inspection results to the FAA. The FAA issued AD 2022-
23-08 to address the unsafe condition on these products.
Actions Since AD 2022-23-08 Was Issued
Since the FAA issued AD 2022-23-08, Transport Canada, which is the
aviation authority for Canada, issued Transport Canada AD CF-2024-46,
dated December 23, 2024 (Transport Canada AD CF-2024-46) (also referred
to as the MCAI). The MCAI states that a fatal DHC-3 airplane accident
occurred on September 4, 2022, at Mutiny Bay, near Freeland, WA.
Witnesses reported that the airplane was in level flight before it
entered a slight climb, then pitched down in a near-vertical descent
until it impacted water resulting in fatal injuries to the pilot and
the nine passengers.
The National Transportation Safety Board (NTSB) carried out the
accident investigation and released a final investigation report on
September 29, 2023. The NTSB noted in the report that the stabilizer
actuator clamp nut on the accident airplane separated from the
stabilizer barrel by unthreading and the lock ring securing the clamp
nut to the barrel was missing. The NTSB also found an unapproved
moisture seal had been installed on the stabilizer actuator, which is
not part of the airplane's type design, leading to increased rotational
friction between the clamp nut and eye bolt, which has the potential to
increase the rate of separation between the clamp nut and barrel in the
absence of the lock ring.
To address the unsafe condition, Transport Canada AD CF-2024-46
requires initial and repetitive inspections of the stabilizer actuator
to confirm that the stabilizer actuator lock ring is present, correctly
seated in the groove in the upper housing, and fully engaged in the
clamp nut. Transport Canada AD CF-2024-46 also requires application of
a witness mark (torque seal) and prohibits the installation of a
stabilizer actuator that has not been inspected in accordance with
Transport Canada AD CF-2024-46 or has not been
[[Page 26230]]
marked. If the lock ring is missing or incorrectly installed, Transport
Canada AD CF-2024-46 requires the rectification of the actuator in
accordance with Viking Service Letter DHC3-SL-27-001, dated October 25,
2022, or replacement with a serviceable actuator, and prohibits the
installation of affected parts.
The FAA is proposing this AD to ensure that the stabilizer actuator
clamp nut does not separate from the stabilizer barrel by unthreading
and to ensure that the lock ring securing the clamp nut to the
stabilizer barrel does not separate. This condition, if not detected
and corrected, could result in a reduction or loss of pitch control
during flight with consequent loss of control of the airplane.
You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2025-1107.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Transport Canada AD CF-2024-46, which specifies
procedures for initial and repetitive inspections of the stabilizer
actuator, applicable corrective actions, and torque seal (witness mark)
application. Transport Canada AD CF-2024-46 also prohibits the
installation of any stabilizer actuator unless it is a serviceable
part.
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 ADDRESSES.
FAA's Determination
These products have been approved by the 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, it 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 on other products of the same type design.
Proposed AD Requirements in This NPRM
This proposed AD would retain none of the requirements of AD 2022-
23-08. This proposed AD would require accomplishing the actions
specified in Canadian AD CF-2024-46 described previously. See
``Differences Between this Proposed AD and the MCAI'' for a discussion
of the general differences included in this proposed AD.
Differences Between This Proposed AD and the MCAI
Where Part V of Transport Canada AD CF-2024-46 specifies installing
a new clamp nut and safety wire on the horizontal stabilizer as an
optional terminating action, this proposed AD would require installing
a secondary retention feature using a method approved by the FAA within
330 hours time-in-service, after the effective date of this AD.
Where Transport Canada AD CF-2024-46 requires reporting any
movement of the lock ring or witness mark to the Transport Canada Web
Service Difficulty Reporting System (WSDRS), this proposed AD would not
require that action.
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 Transport Canada 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 Transport Canada. As a result, the FAA proposes
to incorporate Transport Canada AD CF-2024-46 by reference in the FAA
final rule. This proposed AD would, therefore, require compliance with
Transport Canada AD CF-2024-46 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-2024-46 for compliance will be available at
regulations.gov under Docket No. FAA-2025-1107 after the FAA final rule
is published.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 64 airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:
Estimated Costs
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Cost on U.S.
Action Labor cost Parts cost Cost per product operators
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Inspect lock ring................ 1 work-hour x $85 $0 $85 per inspection $5,440 per
per hour = $85 per cycle. inspection cycle.
inspection cycle.
Apply witness mark (torque seal). 1 work-hour x $85 0 $85................. $5,440.
per hour = $85.
Install secondary retention 17 work-hours x $85 795 $2,240.............. $143,360.
feature. per hour = $1445.
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The FAA estimates the following costs to do any necessary actions
that would be required based on the results of the proposed inspection.
The agency has no way of determining the number of airplanes that might
need these actions:
On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Action Labor cost Parts cost Cost per product
----------------------------------------------------------------------------------------------------------------
Install lock ring if missing or incorrectly 15 work-hours x $85 per hour = $50 $1,325
installed. $1,275.
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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
[[Page 26231]]
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 that the 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:
0
a. Removing Airworthiness Directive 2022-23-08, Amendment 39-22235 (87
FR 66084, November 2, 2022); and
0
b. Adding the following new airworthiness directive:
Viking Air Limited (type certificate previously held by Bombardier
Inc. and de Havilland, Inc.): Docket No. FAA-2025-1107; Project
Identifier MCAI-2024-00784-A.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by August 4, 2025.
(b) Affected ADs
This AD replaces AD 2022-23-08, Amendment 39-22235 (87 FR 66084,
November 2, 2022) (AD 2022-23-08).
(c) Applicability
This AD applies to Viking Air Limited (Viking) (type certificate
previously held by Bombardier Inc. and de Havilland, Inc.) Model
DHC-3 airplanes, certificated in any category, as identified in
Transport Canada AD CF-2024-46, dated December 23, 2024 (Transport
Canada AD CF-2024-46).
(d) Subject
Joint Aircraft System Component (JASC) Code 5520, Elevator
Structure.
(e) Unsafe Condition
This AD was prompted by an investigation of a Viking Model DHC-3
airplane where the lock ring of the stabilizer actuator was found to
be missing. The FAA is issuing this AD to ensure that the stabilizer
actuator clamp nut does not separate from the stabilizer barrel by
unthreading and to ensure that the lock ring securing the clamp nut
to the stabilizer barrel does not separate. This condition, if not
detected and corrected, could result in a reduction or loss of pitch
control during flight with consequent loss of control of the
airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
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-2024-46.
(h) Exceptions to Transport Canada AD CF-2024-46
(1) Where Transport Canada AD CF-2024-46 refers to its effective
date, this AD requires using the effective date of this AD.
(2) Where Transport Canada AD CF-2022-68 requires compliance in
terms of hours air time, this AD requires using hours time-in-
service (TIS).
(3) Where Part V of Transport Canada AD CF-2024-46 specifies
installing a new clamp nut and safety wire on the horizontal
stabilizer as an optional terminating action using FAA Supplemental
Type Certificate SA02761SE, this AD requires installing a secondary
retention feature using a method approved by the FAA within 330
hours time-in-service after the effective date of this AD.
(4) Where Transport Canada AD CF-2024-46 requires reporting any
movement of the lock ring or witness mark to the Transport Canada
Web Service Difficulty Reporting System (WSDRS), this AD does not
require that action.
(i) 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 local Flight
Standards District Office, as appropriate. If sending information
directly to the manager of the International Validation Branch, mail
it to the address 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 local flight standards district office/
certificate holding district office.
(j) Additional Information
For more information about this AD, contact Brenda Buitrago,
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; phone: (516) 228-7368; email:
[email protected].
(k) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference (IBR) 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 the AD specifies otherwise.
(i) Transport Canada AD CF-2024-46, dated December 23, 2024.
(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; phone: (888)
663-3639; email: [email protected]; website: tc.canada.ca/en/
aviation.
(4) You may view this material at FAA, Airworthiness Products
Section, Operational Safety Branch, 901 Locust, Kansas City, MO
64106. For information on the availability of this material at the
FAA, call (817) 222-5110.
(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 June 16, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2025-11327 Filed 6-18-25; 8:45 am]
BILLING CODE 4910-13-P