Rule2026-04280
Airworthiness Directives; BRP-Rotax GmbH & Co KG (Formerly BRP-POWERTRAIN GMBH & CO KG and Bombardier-Rotax GmbH) Engines
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
March 4, 2026
Effective
March 19, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is adopting a new airworthiness directive (AD) for all BRP-Rotax GmbH & Co KG (Rotax) Model 915 iSc2 C24 and 915 iSc3 C24 engines. This AD was prompted by a report of a certain collar nut that was not installed on the propeller gearbox. This AD requires a visual inspection of the propeller gearbox to determine if a collar nut is installed on the propeller shaft and, if not installed, replacement of the propeller gearbox with a serviceable propeller gearbox. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 91 Issue 42 (Wednesday, March 4, 2026)</title>
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[Federal Register Volume 91, Number 42 (Wednesday, March 4, 2026)]
[Rules and Regulations]
[Pages 10513-10515]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-04280]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2026-1321; Project Identifier MCAI-2025-01769-E;
Amendment 39-23261; AD 2026-04-02]
RIN 2120-AA64
Airworthiness Directives; BRP-Rotax GmbH & Co KG (Formerly BRP-
POWERTRAIN GMBH & CO KG and Bombardier-Rotax GmbH) Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule; request for comments.
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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
BRP-Rotax GmbH & Co KG (Rotax) Model 915 iSc2 C24 and 915 iSc3 C24
engines. This AD was prompted by a report of a certain collar nut that
was not installed on the propeller gearbox. This AD requires a visual
inspection of the propeller gearbox to determine if a collar nut is
installed on the propeller shaft and, if not installed, replacement of
the propeller gearbox with a serviceable propeller gearbox. The FAA is
issuing this AD to address the unsafe condition on these products.
DATES: This AD is effective March 19, 2026.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of March 19,
2026.
The FAA must receive comments on this AD by April 20, 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-2026-1321; 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 final rule, 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 Rotax material identified in this AD, contact Rotax,
Rotaxstrasse 1, Gunskirchen, Austria; phone: +43 7246 601 0; website:
<a href="http://www.flyrotax.com">www.flyrotax.com</a>.
<bullet> You may view this material at the FAA, Airworthiness
Products Section, Operational Safety Branch, 1200 District Avenue,
Burlington, MA 01803. For information on the availability of this
material at the FAA, call (817) 222-5110. It is also available at
<a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-2026-1321.
FOR FURTHER INFORMATION CONTACT: David Bergeron, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
phone: (860) 386-1805; email: <a href="/cdn-cgi/l/email-protection#bedadfc8d7da90d490dcdbccd9dbccd1d0fed8dfdf90d9d1c8"><span class="__cf_email__" data-cfemail="066267706f62286c2864637461637469684660676728616970">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written data, views, or arguments
about this final rule. Send your comments using a method listed under
the ADDRESSES section. Include ``Docket No. FAA-2026-1321; Project
Identifier MCAI-2025-01769-E'' at the beginning of your comments. The
most helpful comments reference a specific portion of the final rule,
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 final rule 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 final rule.
[[Page 10514]]
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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to David
Bergeron, 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 European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Union, has issued
EASA Emergency AD 2025-0267-E, dated November 28, 2025 (EASA AD 2025-
0267-E) (also referred to as the MCAI), to correct an unsafe condition
on Rotax Model 915 iSc2 A, 915 iSc3 A, 915 iSc2 C24, 915 iSc3 C24, 916
iSc2 A, 916 iSc3 A, 916 iSc3 B, 916 iSc2 C24, and 916 iSc3 C24 engines.
The MCAI states that an occurrence was reported of the M40 x 1.5 collar
nut that had not been installed on the propeller gearbox of a recently
manufactured engine, which could result in the propeller shaft being
pulled out of the gearbox housing during operation. To address this
potential unsafe condition, Rotax published service material to provide
instructions for inspection of the propeller gearbox and corrective
action if the M40 x 1.5 collar nut is not installed on the propeller
gearbox. This condition, if not detected and corrected, could lead to
an in-flight engine failure and loss of propeller retention, possibly
resulting in loss of control of the airplane.
You may examine the MCAI in the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-1321.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Rotax Alert Service Bulletin ASB-915 i-021R1/ASB-
916 i-009R1, Revision 1, dated November 27, 2025 (published as a single
document) (Rotax ASB-915 i-021R1/ASB-916 i-009R1), which specifies
procedures for a visual inspection of the propeller gearbox to
determine if a collar nut is installed on the propeller shaft and, if
not installed, replacement of the propeller gearbox with a serviceable
propeller gearbox.
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 AD after determining that the unsafe condition described
previously is likely to exist or develop on other products of the same
type design.
AD Requirements
This AD requires accomplishing the actions specified in the
material already described, except as discussed under ``Differences
Between This AD, the MCAI, and the Referenced Material.''
Differences Between This AD, the MCAI, and the Referenced Material
Where EASA AD 2025-0267-E applies to Rotax Model 915 iSc2 A, 915
iSc3 A, 916 iSc2 A, 916 iSc3 A, 916 iSc3 B, 916 iSc2 C24, and 916 iSc3
C24 engines, all serial numbers, this AD does not, as these engine
models do not have an FAA type certificate. Although none of these
models are listed on the current FAA type certificate, certain Rotax
Model 915i and 916i series engines are undergoing FAA validation
towards FAA type certification.
Where Rotax ASB-915 i-021R1/ASB-916 i-009R1 specifies ``If
contamination is found, contact your local ROTAX Authorized
Distributors or their independent Service Centers,'' this AD requires,
before further flight, accomplishing further action in accordance with
a method approved by the Manager, International Validation Branch, FAA;
EASA; or Rotax' EASA Design Organization Approval (DOA). If approved by
the DOA, the approval must include the DOA-authorized signature.
Justification for Immediate Adoption and Determination of the Effective
Date
Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C.
551 et seq.) authorizes agencies to dispense with notice and comment
procedures for rules when the agency, for ``good cause,'' finds that
those procedures are ``impracticable, unnecessary, or contrary to the
public interest.'' Under this section, an agency, upon finding good
cause, may issue a final rule without providing notice and seeking
comment prior to issuance. Further, section 553(d) of the APA
authorizes agencies to make rules effective in less than thirty days,
upon a finding of good cause.
The FAA justifies waiving notice and comment prior to adoption of
this rule because no domestic operators are affected by this AD. It is
unlikely that the FAA will receive any adverse comments or useful
information about this AD from any U.S. operator.
Accordingly, notice and opportunity for prior public comment are
unnecessary, pursuant to 5 U.S.C. 553(b). In addition, for the
foregoing reason(s), the FAA finds that good cause exists pursuant to 5
U.S.C. 553(d) for making this amendment effective in less than 30 days.
Regulatory Flexibility Act
The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because the FAA has determined
that it has good cause to adopt this rule without prior notice and
comment, RFA analysis is not required.
Costs of Compliance
There are no costs of compliance with this AD because there are no
engines with this type certificate on the U.S. Registry.
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.
[[Page 10515]]
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
This AD will not have federalism implications under Executive Order
13132. This AD will 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 this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866, and
(2) Will not affect intrastate aviation in Alaska.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
The Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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:
2026-04-02 BRP-Rotax GmbH & Co KG (formerly BRP-POWERTRAIN GMBH & CO
KG and Bombardier-Rotax GmbH): Amendment 39-23261; Docket No. FAA-
2026-1321; Project Identifier MCAI-2025-01769-E.
(a) Effective Date
This airworthiness directive (AD) is effective March 19, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to all BRP-Rotax GmbH & Co KG (formerly BRP-
POWERTRAIN GMBH & CO KG and Bombardier-Rotax GmbH) (Rotax) Model 915
iSc2 C24 and 915 iSc3 C24 engines.
(d) Subject
Joint Aircraft System Component (JASC) Code 7210, Turbine Engine
Reduction Gear.
(e) Unsafe Condition
This AD was prompted by a report of a certain collar nut that
was not installed on the propeller gearbox. The FAA is issuing this
AD to detect and correct a collar nut that was not installed on the
propeller gearbox. The unsafe condition, if not addressed, could
result in an in-flight engine failure and loss of propeller
retention, possibly resulting in loss of control of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Definition
For the purpose of this AD:
(1) A ``serviceable gearbox'' is a propeller gearbox that meets
one of the conditions in paragraphs (g)(1)(i) through (iv) of this
AD.
(i) A propeller gearbox having Part Number 686790 that has
passed the inspection required by paragraph (h)(1) of this AD.
(ii) A propeller gearbox manufactured after November 18, 2025.
(iii) A propeller gearbox that was overhauled after November 18,
2025.
(iv) A propeller gearbox having a serial number that is not
listed in paragraph 4) Appendix, of Rotax Alert Service Bulletin
ASB-915 i-021R1/ASB-916 i-009R1, Revision 1, dated November 27, 2025
(published as a single document) (Rotax ASB-915 i-021R1/ASB-916 i-
009R1).
(2) An ``affected propeller gearbox'' is a propeller gearbox
that is listed in paragraph 4) Appendix, of Rotax ASB-915 i-021R1/
ASB-916 i-009R1.
(h) Required Actions
(1) Before further flight after the effective date of this AD
and thereafter before further flight after installation of an
affected propeller gearbox, do a visual inspection of the propeller
gearbox for a collar nut installed on the propeller shaft in
accordance with the Accomplishment/Instructions, paragraph 3.5.1) of
Rotax ASB-915 i-021R1/ASB-916 i-009R1.
(2) If, during the inspection required by paragraph (h)(1) of
this AD, any propeller gearbox is found without the collar nut
installed on the propeller shaft, replace the propeller gearbox with
a serviceable propeller gearbox and perform a test run in accordance
with paragraphs (3.5.2) and (3.6) of Rotax ASB-915 i-021R1/ASB-916
i-009R1.
(i) Exception to the Referenced Material
Where Rotax ASB-915 i-021R1/ASB-916 i-009R1 specifies ``If
contamination is found, contact your local ROTAX Authorized
Distributors or their independent Service Centers,'' this AD
requires, before further flight, accomplishing further action in
accordance with a method approved by the Manager, International
Validation Branch, FAA; European Union Aviation Safety Agency
(EASA); or Rotax' EASA Design Organization Approval (DOA). If
approved by the DOA, the approval must include the DOA-authorized
signature.
(j) 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 (k) of
this AD and email to: <a href="/cdn-cgi/l/email-protection#3a7b7775797a5c5b5b145d554c"><span class="__cf_email__" data-cfemail="57161a18141731363679303821">[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.
(k) Additional Information
For more information about this AD, contact David Bergeron,
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; phone: (860) 386-1805; email:
<a href="/cdn-cgi/l/email-protection#7a1e1b0c131e541054181f081d1f0815143a1c1b1b541d150c"><span class="__cf_email__" data-cfemail="fe9a9f88979ad094d09c9b8c999b8c9190be989f9fd0999188">[email protected]</span></a>.
(l) 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) BRP-Rotax GmbH & Co KG Alert Service Bulletin ASB-915 i-
021R1/ASB-916 i-009R1, Revision 1, dated November 27, 2025
(published as a single document).
(ii) [Reserved]
(3) For Rotax material identified in this AD, contact Rotax,
Rotaxstrasse 1, Gunskirchen, Austria; phone: +43 7246 601 0;
website: <a href="http://www.flyrotax.com">www.flyrotax.com</a>.
(4) You may view this material at the FAA, Airworthiness
Products Section, Operational Safety Branch, 1200 District Avenue,
Burlington, MA 01803. 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#c0a6b2eea9aeb3b0a5a3b4a9afae80aea1b2a1eea7afb6"><span class="__cf_email__" data-cfemail="7117035f181f0201141205181e1f311f1003105f161e07">[email protected]</span></a>.
Issued on February 10, 2026.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2026-04280 Filed 3-3-26; 8:45 am]
BILLING CODE 4910-13-P
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