Proposed Rule2025-06367
Airworthiness Directives; MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier, Inc.) Airplanes
Primary source
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Published
April 15, 2025
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to adopt a new airworthiness directive (AD) for all MHI RJ Aviation ULC Model CL-600-2C10 (Regional Jet Series 700, 701 & 702), CL-600-2C11 (Regional Jet Series 550), Model CL-600-2D15 (Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900), and CL-600-2E25 (Regional Jet Series 1000). This proposed AD was prompted by an engine indicating and crew alerting system (EICAS) STAB TRIM Caution message that was posted, and subsequent repair that found prematurely worn teeth on a rubber bull gear (RBG) wheel in the horizontal stabilizer trim actuator (HSTA). This proposed AD would require an inspection for part numbers and on-condition replacement of affected RBG wheels and prohibit the installation of affected parts under certain conditions, as specified in a Transport Canada AD, which is proposed for incorporation by reference (IBR). The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 90 Issue 71 (Tuesday, April 15, 2025)</title>
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[Federal Register Volume 90, Number 71 (Tuesday, April 15, 2025)]
[Proposed Rules]
[Pages 15664-15667]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-06367]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-0619; Project Identifier MCAI-2024-00372-T]
RIN 2120-AA64
Airworthiness Directives; MHI RJ Aviation ULC (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 MHI RJ Aviation ULC Model CL-600-2C10 (Regional Jet Series 700,
701 & 702), CL-600-2C11 (Regional Jet Series 550), Model CL-600-2D15
(Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900), and
CL-600-2E25 (Regional Jet Series 1000). This proposed AD was prompted
by an engine indicating and crew alerting system (EICAS) STAB TRIM
Caution message that was posted, and subsequent repair that found
prematurely worn teeth on a rubber bull gear (RBG) wheel in the
horizontal stabilizer trim actuator (HSTA). This proposed AD would
require an inspection for part numbers and on-condition replacement of
affected RBG wheels and prohibit the installation of affected parts
under certain conditions, as specified in a Transport Canada AD, which
is proposed for incorporation by reference (IBR). 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 May 30,
2025.
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.
[[Page 15665]]
<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-2025-0619; 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#aefaed80efc7dcd9c1dcdac6c7c0cbddddeac7dccbcddac7d8cbdd83edc1c0ddc7c9c0cbddcacbc0cfd8c7c9cfccc7c2c7dacb80faedeedacd80c9cd80cdcf"><span class="__cf_email__" data-cfemail="47130469062e35302835332f2e29223434032e352224332e3122346a042829342e2029223423222926312e2026252e2b2e3322691304073324692024692426">[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-2025-0619.
<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: Isabel Saltzman, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
telephone 516-228-7300; email <a href="/cdn-cgi/l/email-protection#e7deca869194ca899e868488ca848894a7818686c9808891"><span class="__cf_email__" data-cfemail="291004485f5a044750484a46044a465a694f4848074e465f">[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 to an address listed
under the ADDRESSES section. Include ``Docket No. FAA-2025-0619;
Project Identifier MCAI-2024-00372-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
Isabel Saltzman, Aviation Safety Engineer, FAA, 1600 Stewart Avenue,
Suite 410, Westbury, NY 11590; telephone 516-228-7300; email <a href="/cdn-cgi/l/email-protection#487165293e3b652631292b27652b273b082e2929662f273e"><span class="__cf_email__" data-cfemail="390014584f4a145740585a56145a564a795f5858175e564f">[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-2024-25, dated June 28, 2024 (Transport
Canada AD CF-2024-25) (also referred to as the MCAI), to correct an
unsafe condition for all MHI RJ Aviation ULC Model CL-600-2C10
(Regional Jet Series 700, 701 & 702), CL-600-2C11 (Regional Jet Series
550), CL-600-2D15 (Regional Jet Series 705), CL-600-2D24 (Regional Jet
Series 900), and CL-600-2E25 (Regional Jet Series 1000) airplanes. The
MCAI states that an in-service event occurred where an EICAS STAB TRIM
Caution message was posted. Following the occurrence, the HSTA was
removed and returned to the vendor for repair. During repair, it was
discovered that one of the two RBG wheels had worn teeth. Investigation
revealed quality issues involving the machining and surface treatment
of the HSTA RBG wheel had caused premature wear of the wheel teeth.
Further investigation determined that this quality issue affects a
limited number of RBG wheels and HSTA serial numbers. Wear of the RBG
wheel teeth could cause a failure of the horizontal stabilizer trim
system.
The FAA is proposing this AD to address the unsafe condition on
these products.
You may examine the MCAI in the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-0619.
Material Incorporated by Reference Under 1 CFR Part 51
Transport Canada AD CF-2024-25 specifies procedures for a part
number check and, if necessary, replacement of affected RBG wheels in
certain HSTAs. Transport Canada AD CF-2024-25 also prohibits the
installation of affected parts under certain conditions. 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
This product has been approved by the aviation authority of another
country and is 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
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-2024-25 described previously, except for any
differences identified as exceptions in the regulatory text of this
proposed AD.
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-2024-25 by reference
in the FAA final rule. This proposed AD would, therefore, require
compliance with Transport Canada AD CF-2024-25 in its entirety through
that incorporation, except for any differences identified as exceptions
in the regulatory text of this
[[Page 15666]]
proposed AD. Material required by Transport Canada AD CF-2024-25 for
compliance will be available at <a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-
2025-0619 after the FAA final rule is published.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 460 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:
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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1 work-hour x $85 per hour = $85.... None.......................... $85 $39,100
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The FAA estimates the following costs to do any necessary on-
condition action 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 this on-condition action:
Estimated Costs of On-Condition Actions
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Labor cost Parts cost Cost per product
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30 work-hours x $85 per hour = * $0 $2,550 (up to 32
$2,550. affected parts in
the fleet).
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* The FAA has received no definitive data on which to base the cost
estimates for the on-condition parts 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:
MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier,
Inc.): Docket No. FAA-2025-0619; Project Identifier MCAI-2024-00372-
T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by May 30, 2025.
(b) Affected ADs
None.
(c) Applicability
This AD applies to all MHI RJ Aviation ULC (Type Certificate
previously held by Bombardier, Inc.) airplanes identified in
paragraphs (c)(1) through (5) of this AD, certificated in any
category.
(1) Model CL-600-2C10 (Regional Jet Series 700, 701 & 702)
airplanes.
(2) Model CL-600-2C11 (Regional Jet Series 550) airplanes.
(3) Model CL-600-2D15 (Regional Jet Series 705) airplanes.
(4) Model CL-600-2D24 (Regional Jet Series 900) airplanes.
(5) Model CL-600-2E25 (Regional Jet Series 1000) airplanes.
(d) Subject
Air Transport Association (ATA) of America Code 27, Flight
Controls.
(e) Unsafe Condition
This AD was prompted by a report of an in-service event where an
engine indicating and crew alerting system (EICAS) STAB TRIM Caution
message was posted, and subsequent repair found prematurely worn
teeth on a rubber bull gear (RBG) wheel in the horizontal stabilizer
trim actuator (HSTA). The FAA is issuing this AD to address
premature wear of the RBG wheel teeth. The unsafe condition, if not
addressed, could result in a failure of the horizontal stabilizer
trim system.
(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
[[Page 15667]]
AD CF-2024-25, dated June 28, 2024 (Transport Canada AD CF-2024-25).
(h) Exception to Transport Canada AD CF-2024-25
(1) Where Transport Canada AD CF-2024-25 refers to its effective
date, this AD requires using the effective date of this AD.
(2) Where Transport Canada AD CF-2024-25 refers to ``Section
1.A. of the applicable MHIRJ SB,'' this AD requires replacing that
text with ``Section 1.A. of MHIRJ Service Bulletin 670BA-27-077,
dated April 16, 2024.''
(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:
<a href="/cdn-cgi/l/email-protection#60212d2f23200601014e070f16"><span class="__cf_email__" data-cfemail="7a3b3735393a1c1b1b541d150c">[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 4a manufacturer, the instructions must
be accomplished using a method approved by the Manager,
International Validation Branch, FAA; or Transport Canada; or MHI
RJ'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 Isabel Saltzman,
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; telephone 516-228-7300; email <a href="/cdn-cgi/l/email-protection#2c15014d5a5f0142554d4f43014f435f6c4a4d4d024b435a"><span class="__cf_email__" data-cfemail="e1d8cc809792cc8f9880828ecc828e92a1878080cf868e97">[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-2024-25, dated June 28, 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; telephone 888-
663-3639; email <a href="/cdn-cgi/l/email-protection#87d3c4a9c6eef5f0e8f5f3efeee9e2f4f4c3eef5e2e4f3eef1e2f4aac4e8e9f4eee0e9e2f4e3e2e9e6f1eee0e6e5eeebeef3e2a9d3c4c7f3e4a9e0e4a9e4e6"><span class="__cf_email__" data-cfemail="4216016c032b30352d30362a2b2c273131062b302721362b3427316f012d2c312b252c273126272c23342b2523202b2e2b36276c16010236216c25216c2123">[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="ccaabee2a5a2bfbca9afb8a5a3a28ca2adbeade2aba3ba">[email protected]</span></a>.
Issued on April 9, 2025.
Paul R. Bernado,
Acting Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2025-06367 Filed 4-14-25; 8:45 am]
BILLING CODE 4910-13-P
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