Proposed Rule2026-06788
Airworthiness Directives; Bell Textron Canada Limited Helicopters
Primary source
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Published
April 8, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to supersede Airworthiness Directive (AD) AD 2024-02-55, which applies to certain Bell Textron Canada Limited (BTCL) Model 505 helicopters. AD 2024-02-55 requires initial and recurring inspections of the vertical stabilizer top end cap assembly and corrective action if a crack is found. Since the FAA issued AD 2024-02- 55, the manufacturer introduced a new one-piece vertical stabilizer machined top end cap assembly, which is implemented during production, and designed a new replacement for the vertical stabilizer machined top end cap assembly currently in service. This proposed AD would continue to require the inspection requirements of AD 2024-02-55 and would limit the applicability to exclude certain serial numbered BTCL Model 505 helicopters with an improved design vertical stabilizer top end cap installed at production. This proposed AD would also require replacing the vertical stabilizer top end cap assembly with an improved design top end cap assembly, which would constitute terminating action for the recurring detailed visual inspections. 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 67 (Wednesday, April 8, 2026)</title>
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[Federal Register Volume 91, Number 67 (Wednesday, April 8, 2026)]
[Proposed Rules]
[Pages 17772-17775]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-06788]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2026-3477; Project Identifier MCAI-2025-01195-R]
RIN 2120-AA64
Airworthiness Directives; Bell Textron Canada Limited Helicopters
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) AD
2024-02-55, which applies to certain Bell Textron Canada Limited (BTCL)
Model 505 helicopters. AD 2024-02-55 requires initial and recurring
inspections of the vertical stabilizer top end cap assembly and
corrective action if a crack is found. Since the FAA issued AD 2024-02-
55, the manufacturer introduced a new one-piece vertical stabilizer
machined top end cap assembly, which is implemented during production,
and designed a new replacement for the vertical stabilizer machined top
end cap assembly currently in service. This proposed AD would continue
to require the inspection requirements of AD 2024-02-55 and would limit
the applicability to exclude certain serial numbered BTCL Model 505
helicopters with an improved design vertical stabilizer top end cap
installed at production. This proposed AD would also require replacing
the vertical stabilizer top end cap assembly with an improved design
top end cap assembly, which would constitute terminating action for the
recurring detailed visual inspections. The FAA is proposing this AD to
address the unsafe condition on these products.
DATES: The FAA must receive comments on this NPRM by May 26, 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-2026-3477; 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#f3a7b0ddb29a81849c81879b9a9d968080b79a819690879a859680deb09c9d809a949d968097969d92859a9492919a9f9a8796dda7b0b38790dd9490dd9092"><span class="__cf_email__" data-cfemail="fda9bed3bc948f8a928f89959493988e8eb9948f989e89948b988ed0be92938e949a93988e9998939c8b949a9c9f9491948998d3a9bebd899ed39a9ed39e9c">[email protected]</span></a>;
[[Page 17773]]
internet tc.canada.ca/en/aviation. You may find the Transport Canada
material on the Transport Canada website at <a href="http://wwwapps.tc.gc.ca/Saf-Sec-Sur/2/cawis-swimn/ad_qs1.aspx">wwwapps.tc.gc.ca/Saf-Sec-Sur/2/cawis-swimn/ad_qs1.aspx</a>.
<bullet> You may view this material at the FAA, Office of the
Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-
321, Fort Worth, TX 76177. For information on the availability of this
material at the FAA, call (817) 222-5110.
FOR FURTHER INFORMATION CONTACT: Promita Dey, Aviation Safety Engineer,
FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (913)
563-8269; email: <a href="/cdn-cgi/l/email-protection#671715080a0e13064903021e2701060649000811"><span class="__cf_email__" data-cfemail="8bfbf9e4e6e2ffeaa5efeef2cbedeaeaa5ece4fd">[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 ADDRESSES. Include ``Docket No. FAA-2026-3477; Project Identifier
MCAI-2025-01195-R'' 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
<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
Promita Dey, 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 2024-02-55, Amendment 39-22674 (89 FR 14576,
February 28, 2024) (AD 2024-02-55), for BTCL Model 505 helicopters
having serial numbers 65011 and subsequent. AD 2024-02-55 was prompted
by an MCAI issued by Transport Canada, which is the aviation authority
for Canada. Transport Canada issued Transport Canada Emergency AD CF-
2024-03, dated January 25, 2024 (Transport Canada AD CF-2024-03), to
correct an unsafe condition identified as reports of cracked vertical
stabilizer top end cap assemblies.
AD 2024-02-55 requires initial and recurring inspections of the
vertical stabilizer top end cap assembly, and if a crack is found,
replacement of the top end cap. The FAA issued AD 2024-02-55 to address
cracking in the vertical stabilizer top end cap assembly. This
condition, if not addressed, could result in the antenna or tuning
weight departing from the helicopter and impacting and damaging the
tail rotor, which could result in the loss of directional control of
the helicopter.
Actions Since AD 2024-02-55 Was Issued
Since the FAA issued AD 2024-02-55, Transport Canada superseded
Transport Canada AD CF-2024-03 and issued Transport Canada AD CF-2025-
32, dated July 2, 2025 (Transport Canada AD CF-2025-32) (also referred
to as the MCAI). The MCAI states that a new one-piece vertical
stabilizer machined top end cap assembly, having part number (P/N) SLS-
030-701-149, was implemented into the Bell 505 production line, and a
new machined top end cap assembly, P/N SLS-704-701-101, was developed
as a replacement for the top end cap assembly P/N SLS-030-701-125 that
is currently in service. The MCAI requires repetitive inspections of
the vertical stabilizer top end cap assembly until the required
replacement with a new machined top end cap assembly, P/N SLS-704-701-
101, which is considered terminating action for the repetitive
inspections.
You may examine the MCAI in the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-3477.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Transport Canada AD CF-2025-32, which specifies
procedures for accomplishing a one-time detailed visual inspection of
the vertical stabilizer top end cap assembly for cracking; replacing
any cracked vertical stabilizer top end cap assembly; repetitively
inspecting vertical stabilizer top end cap assembly P/N SLS-030-701-
125; and replacing vertical stabilizer top end cap assembly P/N SLS-
030-701-125 with vertical stabilizer top end cap assembly P/N SLS-704-
701-101.
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
(CAA) 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 proposing
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 continue to require the inspection
requirements of AD 2024-02-55 and would also require accomplishing the
actions specified in Transport Canada AD CF-2025-32, described
previously as incorporated by reference, except for any differences
identified as exceptions in the regulatory text of this proposed AD.
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 the material referenced in Transport Canada AD CF-2025-32
specifies to contact the manufacturer if the drilled holes can no
longer go beyond the allowable dimensions, this AD requires corrective
action to be done in accordance with a method approved by the Manager,
International Validation Branch, FAA; or Transport Canada; or Bell
Textron Canada Limited Transport Canada Design Organization Approval
(DOA). If approved by the DOA, the approval must include the DOA-
authorized signature.
[[Page 17774]]
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 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-2025-32 by reference in the FAA final rule. This
proposed AD would, therefore, require compliance with Transport Canada
AD CF-2025-32 in its entirety through that incorporation, except for
any differences identified as exceptions in the regulatory text of this
proposed AD. Material required in Transport Canada AD CF-2025-32 for
compliance will be available at <a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-
2026-3477 after the FAA final rule is published.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 150 helicopters of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Initial inspection of vertical 2 work-hours x $85 per $0 $170 $25,500
stabilizer top end assembly. hour = $170.
Recurring inspections of vertical 1 work-hour x $85 per 0 85 12,750
stabilizer top end assembly. hour = $85.
Replacement of the vertical stabilizer 6 work-hours (not 2,000 2,510 376,500
top end assembly. including 16 hours to
cure) x $85 per hour =
$510.
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The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, some 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 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 2024-02-55, Amendment 39-22674 (89
FR 14576, February 28, 2024); and
0
b. Adding the following new airworthiness directive:
Bell Textron Canada Limited: Docket No. FAA-2026-3477; Project
Identifier MCAI-2025-01195-R.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by May 26, 2026.
(b) Affected ADs
This AD replaces AD 2024-02-55, Amendment 39-22674 (89 FR 14576,
February 28, 2024).
(c) Applicability
This AD applies to Bell Textron Canada Limited Model 505
helicopters, certificated in any category, as identified in
Transport Canada AD CF-2025-32, dated July 2, 2025 (Transport Canada
AD CF-2025-32).
(d) Subject
Joint Aircraft System Component (JASC) Code: 5530, Vertical
Stabilizer Structure.
(e) Unsafe Condition
This AD was prompted by multiple occurrences of the vertical
stabilizer top end cap assembly being found cracked, with some cases
including the departure of the navigation/very high frequency omni-
directional range/glide slope antenna and tuning weight from the
helicopter during flight. The FAA is issuing this AD to address
cracking in the vertical stabilizer top end cap assembly. The unsafe
condition, if not addressed, could result in the antenna or tuning
weight departing from the helicopter and impacting and damaging the
tail rotor, which could result in the loss of directional control of
the helicopter.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Requirements
Except as specified in paragraphs (h) and (i) of this AD: Comply
with all required actions and compliance times specified in, and in
accordance with, Transport Canada AD CF-2025-32.
(h) Exceptions to Transport Canada AD CF-2025-32
(1) Where Transport Canada AD CF-2025-32 refers to its effective
date, this AD requires using the effective date of this AD.
[[Page 17775]]
(2) Where Transport Canada AD CF-2025-32 requires compliance in
terms of hours air time, this AD requires using hours time-in-
service.
(3) Where the material referenced in Transport Canada AD CF-
2025-32 specifies discarding parts, this AD requires removing those
parts from service.
(4) Where the material referenced in Transport Canada AD CF-
2025-32 specifies damage, for the purposes of this AD, damage can be
indicated by, but not limited to, cracking.
(5) Where the material referenced in Transport Canada AD CF-
2025-32 specifies to contact the manufacturer if the drilled holes
can no longer go beyond the allowable dimensions, this AD requires
corrective action in accordance with a method approved by the
Manager, International Validation Branch, FAA; or Transport Canada;
or Bell Textron Canada Limited Transport Canada Design Organization
Approval (DOA). If approved by the DOA, the approval must include
the DOA-authorized signature.
(i) No Reporting Requirement
Although the service material referenced in Transport Canada AD
CF-2025-32 specifies submitting certain information to the
manufacturer, this AD does not include that action.
(j) Credit for Previous Actions
This paragraph provides credit for the actions required by
paragraph 1. of Transport Canada AD CF-2025-32, if those actions
were performed before the effective date of this AD using Bell
Textron Canada Limited Alert Service Bulletin (ASB) 505-24-38, dated
January 24, 2024.
(k) Alternative Methods of Compliance (AMOCs)
(1) 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, send
it to the attention of the person identified in paragraph (l) of
this AD and email to: <a href="/cdn-cgi/l/email-protection#ffbeb2b0bcbf999e9ed1989089"><span class="__cf_email__" data-cfemail="81c0cccec2c1e7e0e0afe6eef7">[email protected]</span></a>.
(2) 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.
(l) Additional Information
For more information about this AD, contact Promita Dey,
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; phone: (913) 563-8269; email:
<a href="/cdn-cgi/l/email-protection#3c4c4e535155485d125859457c5a5d5d125b534a"><span class="__cf_email__" data-cfemail="5d2d2f323034293c733938241d3b3c3c733a322b">[email protected]</span></a>.
(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 the AD specifies otherwise.
(i) Transport Canada AD CF-2025-32, dated July 2, 2025.
(ii) [Reserved]
(3) For Transport Canada material identified in this AD, contact
Transport Canada National Aircraft Certification, 159 Cleopatra
Drive, Nepean, Ontario, K1A 0N5, Canada; phone 888-663-3639; email
<a href="/cdn-cgi/l/email-protection#95c1d6bbd4fce7e2fae7e1fdfcfbf0e6e6d1fce7f0f6e1fce3f0e6b8d6fafbe6fcf2fbf0e6f1f0fbf4e3fcf2f4f7fcf9fce1f0bbc1d6d5e1f6bbf2f6bbf6f4"><span class="__cf_email__" data-cfemail="f6a2b5d8b79f84819984829e9f98938585b29f849395829f809385dbb59998859f9198938592939897809f9197949f9a9f8293d8a2b5b68295d89195d89597">[email protected]</span></a>;
internet tc.canada.ca/en/aviation. You may find the Transport Canada
material on the Transport Canada website at <a href="http://wwwapps.tc.gc.ca/Saf-Sec-Sur/2/cawis-swimn/ad_qs1.aspx">wwwapps.tc.gc.ca/Saf-Sec-Sur/2/cawis-swimn/ad_qs1.aspx</a>.
(4) You may view this material at the FAA, Office of the
Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-
321, Fort Worth, TX 76177. 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 <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#482e3a6621263b382d2b3c2127260826293a29662f273e"><span class="__cf_email__" data-cfemail="791f0b5710170a091c1a0d1016173917180b18571e160f">[email protected]</span></a>.
Issued on April 6, 2026.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2026-06788 Filed 4-7-26; 8:45 am]
BILLING CODE 4910-13-P
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