[Federal Register Volume 89, Number 174 (Monday, September 9, 2024)]
[Proposed Rules]
[Pages 73009-73014]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-20244]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-1896; Project Identifier MCAI-2023-00978-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 certain MHI RJ Aviation ULC Model CL-600-2B19 (Regional Jet Series 
100 and 440), CL-600-2C10 (Regional Jet Series 700, 701, and 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. AD 2023-10-02 was prompted by the 
determination that radio altimeters cannot be relied on to perform 
their intended function if they experience interference from wireless 
broadband operations in the 3.7-3.98 GHz frequency band (5G C-Band). 
This AD was prompted by the determination that this interference can 
also result in certain failure messages being inhibited longer than 
intended. This proposed AD would require installing a new radio 
frequency (RF) bandpass filter on the coaxial line between the radio 
altimeter and the receive antenna in the aft equipment compartment. 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 October 24, 
2024.

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 regulations.gov. 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 regulations.gov under 
Docket No. FAA-2024-1896; 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 MHI RJ material identified in this proposed AD, 
contact MHI RJ Aviation Group, Customer Response Center, 3655 Ave. des 
Grandes-Tourelles, Suite 110, Boisbriand, Qu[eacute]bec J7H 0E2 Canada; 
North America toll-free telephone 833-990-7272 or direct-dial telephone 
450-990-7272; fax 514-855-8501; email <a href="/cdn-cgi/l/email-protection#186c707c367b6a7258247938706a7d7e25" http: mhirj.com">mhirj.com</a>">thd.crj@mhirj.com</a>; website 
mhirj.com.
    <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: Steven Dzierzynski, Aviation Safety 
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
telephone 516-228-7300; email <a href="/cdn-cgi/l/email-protection#e2dbcf839491cf8c9b83818dcf818d91a2848383cc858d94"><span class="__cf_email__" data-cfemail="b58c98d4c3c698dbccd4d6da98d6dac6f5d3d4d49bd2dac3">[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 ADDRESSES. Include ``Docket No. FAA-2024-1896; Project Identifier 
MCAI-2023-00978-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 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 
Steven Dzierzynski, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, 
Suite 410, Westbury, NY 11590; telephone 516-228-7300; email <a href="/cdn-cgi/l/email-protection#7b42561a0d085615021a1814561814083b1d1a1a551c140d"><span class="__cf_email__" data-cfemail="033a2e6275702e6d7a62606c2e606c70436562622d646c75">[email protected]</span></a>. Any commentary that the FAA receives that is not 
specifically designated as CBI will be placed in the public docket for 
this rulemaking.

[[Page 73010]]

Background

    The FAA issued AD 2023-10-02, Amendment 39-22438 (88 FR 34065, May 
26, 2023) (AD 2023-10-02) to address the effect of interference from 
wireless broadband operations in the 5G C-Band on all transport and 
commuter category airplanes equipped with a radio altimeter. AD 2023-
10-02 was prompted by a determination that radio altimeters cannot be 
relied upon to perform their intended function if they experience 
interference from wireless broadband operations in the 5G C-Band. AD 
2023-10-02 requires revising the limitations section of the existing 
airplane flight manual to incorporate limitations prohibiting transport 
and commuter category airplanes from performing certain low-visibility 
landing operations at any airport unless they have upgraded their radio 
altimeters. Transport Canada, which is the aviation authority for 
Canada, issued corresponding Transport Canada AD CF-2023-46, dated June 
30, 2023, to require similar limitations on flight operations requiring 
radio altimeter data in U.S. airspace affected by 5G C-Band wireless 
signals.
    Additionally, Transport Canada has issued Transport Canada AD CF-
2023-62R1, dated November 21, 2023 (referred to as ``the MCAI''), for 
certain serial-numbered MHI RJ Aviation ULC Model CL-600-2B19 (Regional 
Jet Series 100 and 440), CL-600-2C10 (Regional Jet Series 700, 701, and 
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, in addition 
to the effects of 5G C-Band broadband interference identified in FAA AD 
2023-10-02, MHI RJ has determined that 5G C-Band broadband interference 
can result in certain failure messages and aural alerts being inhibited 
longer than intended. Specifically, this can result in the inhibition 
of hydraulic system #3 and wing anti-ice overheat failure messages such 
that flightcrew are unable to perform appropriate airplane flight 
manual (AFM) procedures in the time needed to prevent loss of elevator 
control due to hydraulic system overheat and wing structural damage due 
to wing anti-ice system overheat. This condition, if not corrected, 
could result in delayed flightcrew response leading to loss of 
continued safe flight and landing.
    The MCAI requires the installation of a new RF bandpass filter on 
the coaxial line between the radio altimeter and the receive antenna in 
the aft equipment compartment. For airplanes with a dual radio 
altimeter configuration, the MCAI requires a filter to be installed on 
both systems or on one system provided the second system is 
deactivated. When the airplane is modified as specified in the MCAI, 
the configuration with the RF bandpass filter installed has been 
determined to be ``radio altimeter tolerant.'' The actions of the MCAI 
apply only to airplanes operating within the contiguous U.S. airspace.
    The FAA is proposing this AD because radio altimeter anomalies can 
result in the inhibition of certain failure messages such that the 
flightcrew are unable to perform appropriate AFM procedures in the time 
needed to prevent loss of elevator control due to hydraulic system 
overheat and wing structural damage due to wing anti-ice system 
overheat, possibly resulting in delayed flightcrew response leading to 
loss of continued safe flight and landing.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2024-1896.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed MHI RJ Service Bulletins 601R-34-152, Revision D, 
dated May 11, 2023, and 670BA-34-054, dated February 20, 2023. This 
material specifies procedures for installing a new RF bandpass filter 
on the coaxial line between the radio altimeter and the receive antenna 
in the aft equipment compartment. These documents are distinct since 
they apply to different airplane models. 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 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. This AD would not apply to airplanes 
that have been modified to be a radio altimeter tolerant airplane under 
the requirements of AD 2023-10-02.

Differences Between the MCAI and This NPRM

    Although the actions of the MCAI apply only to Canadian-registered 
airplanes operating within the contiguous U.S. airspace, this proposed 
AD would apply to U.S.-registered airplanes operating in any airspace. 
The FAA has determined that the expansion of 5G C-band has occurred in 
other countries, such as Canada and Brazil, in which 5G C-band 
interference is expected.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect up to 873 airplanes of U.S. registry. However, many of these 
airplanes may already have a bandpass filter installed in compliance 
with AD 2023-10-02 and would not have any costs because of this 
proposed AD. The FAA estimates the following costs to comply with this 
proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                    Cost per
                  Labor cost                      Parts cost        product           Cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
58 work-hours x $85 per hour = $4,930........         $53,647          $58,577   Up to $51,137,721.
----------------------------------------------------------------------------------------------------------------

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

[[Page 73011]]

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-2024-1896; Project Identifier MCAI-2023-00978-
T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by October 24, 2024.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to the MHI RJ Aviation ULC (Type Certificate 
previously held by Bombardier Inc.) airplanes identified in 
paragraphs (c)(1) through (6) of this AD, certificated in any 
category, that are equipped with a radio altimeter and not 
determined to be a radio altimeter tolerant airplane as defined in 
paragraph (g) of this AD.
    (1) Model CL-600-2B19 (Regional Jet Series 100 and 440) 
airplanes, serial number (S/N) 7002 through 8113.
    (2) Model CL-600-2C10 (Regional Jet Series 700, 701, and 702) 
airplanes, S/N 10002 through 10999.
    (3) Model CL-600-2C11 (Regional Jet Series 550) airplanes, S/N 
10002 through 10999.
    (4) Model CL-600-2D15 (Regional Jet Series 705) airplanes, S/N 
15001 through 15990.
    (5) Model CL-600-2D24 (Regional Jet Series 900) airplanes, S/N 
15001 through 15990.
    (6) Model CL-600-2E25 (Regional Jet Series 1000) airplanes, S/N 
19013 through 19990.

(d) Subject

    Air Transport Association (ATA) of America Code 34, Navigation.

(e) Unsafe Condition

    This AD was prompted by the determination that radio altimeters 
cannot be relied upon to perform their intended function if they 
experience interference from wireless broadband operations in the 
3.7-3.98 GHz frequency band (5G C-Band). The FAA is issuing this AD 
because radio altimeter anomalies can result in the inhibition of 
certain failure messages such that the flightcrew are unable to 
perform appropriate airplane flight manual procedures in the time 
needed to prevent loss of elevator control due to hydraulic system 
overheat and wing structural damage due to wing anti-ice system 
overheat, possibly resulting in delayed flightcrew response leading 
to loss of continued safe flight and landing.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Definitions

    For purposes of this AD, a ``radio altimeter tolerant airplane'' 
is one for which the radio altimeter, as installed, demonstrates the 
tolerances specified in paragraphs (g)(1) and (2) of this AD, using 
a method approved by the FAA. No actions are required by this AD for 
radio altimeter tolerant airplanes.
    (1) Tolerance to radio altimeter interference, for the 
fundamental emissions (3.7-3.98 GHz), at or above the power spectral 
density (PSD) curve threshold specified in figure 1 to paragraph 
(g)(1) of this AD.

Figure 1 to Paragraph (g)(1)--Fundamental Effective Isotropic PSD at 
Outside Interface of Airplane Antenna

[[Page 73012]]

[GRAPHIC] [TIFF OMITTED] TP09SE24.006

    (2) Tolerance to radio altimeter interference, for the spurious 
emissions (4.2-4.4 GHz), at or above the PSD curve threshold 
specified in figure 2 to paragraph (g)(2) of this AD.

Figure 2 to Paragraph (g)(2)--Spurious Effective Isotropic PSD at 
Outside Interface of Airplane Antenna

[[Page 73013]]

[GRAPHIC] [TIFF OMITTED] TP09SE24.007

(h) Filter Installation: Model CL-600-2B19

    For Model CL-600-2B19 airplanes: Within 2,300 flight hours or 12 
months after the effective date of this AD, whichever occurs first, 
install a radio frequency (RF) bandpass filter on each radio 
altimeter in accordance with the applicable parts of the 
Accomplishment Instructions in MHI RJ Service Bulletin 601R-34-152, 
Revision D, dated May 11, 2023. Alternatively, airplanes with a dual 
radio altimeter configuration may comply with this paragraph by 
installing an RF bandpass filter on one radio altimeter and 
deactivating the second radio altimeter in accordance with the 
applicable parts of the Accomplishment Instructions in MHI RJ 
Service Bulletin 601R-34-152, Revision D, dated May 11, 2023.

(i) Filter Installation: Model CL-600-2C10, CL-600-2C11, CL-600-2D15, 
and CL-600-2D24

    For Model CL-600-2C10, CL-600-2C11, CL-600-2D15, and CL-600-2D24 
airplanes: Within 2,100 flight hours or 12 months after the 
effective date of this AD, whichever occurs first, install an RF 
bandpass filter on each radio altimeter in accordance with the 
applicable parts of the Accomplishment Instructions in MHI RJ 
Service Bulletin 670BA-34-054, dated February 20, 2023. 
Alternatively, airplanes with a dual radio altimeter configuration 
may comply with this paragraph by installing an RF bandpass filter 
on one radio altimeter and deactivating the second radio altimeter 
in accordance with the applicable parts of the Accomplishment 
Instructions in MHI RJ Service Bulletin 670BA-34-054, dated February 
20, 2023.

(j) Filter Installation: Model CL-600-2E25

    For Model CL-600-2E25 airplanes: Before the next flight in the 
contiguous U.S. airspace after the effective date of this AD, 
install an RF bandpass filter on each radio altimeter in accordance 
with the applicable parts of the Accomplishment Instructions in MHI 
RJ Service Bulletin 670BA-34-054, dated February 20, 2023.

[[Page 73014]]

(k) Credit for Previous Actions

    For Model CL-600-2B19 airplanes: This paragraph provides credit 
for the actions required by paragraph (h) of this AD, if those 
actions were performed before the effective date of this AD using 
the material in paragraphs (k)(1) through (4) of this AD, provided 
the electrical idents for coax cables are installed using Part G of 
the Accomplishment Instructions in MHI RJ Service Bulletin 601R-34-
152, Revision D, dated May 11, 2023, within the compliance time 
specified in paragraph (h) of this AD.
    (1) MHI RJ Service Bulletin 601R-34-152, dated February 14, 
2023.
    (2) MHI RJ Service Bulletin 601R-34-152, Revision A, dated 
February 28, 2023.
    (3) MHI RJ Service Bulletin 601R-34-152, Revision B, dated March 
28, 2023.
    (4) MHI RJ Service Bulletin 601R-34-152, Revision C, dated April 
20, 2023.

(l) 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, mail it to the address identified 
in paragraph (m) of this AD. Information may be emailed to: 9-AVS-
<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="99d7c0d8dad6b4dad6cad9fff8f8b7fef6ef">[email protected]</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 a manufacturer, the instructions must be 
accomplished using a method approved by the Manager, International 
Validation Branch, FAA; or Transport Canada; or MHI RJ Aviation 
ULC's Transport Canada Design Approval Organization (DAO). If 
approved by the DAO, the approval must include the DAO-authorized 
signature.

(m) Additional Information

    For more information about this AD, contact Steven Dzierzynski, 
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; telephone 516-228-7300; email <a href="/cdn-cgi/l/email-protection#89b0a4e8fffaa4e7f0e8eae6a4eae6fac9efe8e8a7eee6ff"><span class="__cf_email__" data-cfemail="f1c8dc908782dc9f8890929edc929e82b1979090df969e87">[email protected]</span></a>.

(n) 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) MHI RJ Service Bulletin 601R-34-152, Revision D, dated May 
11, 2023.
    (ii) MHI RJ Service Bulletin 670BA-34-054, dated February 20, 
2023.
    (3) For MHI RJ material identified in this AD, contact MHI RJ 
Aviation Group, Customer Response Center, 3655 Ave. des Grandes-
Tourelles, Suite 110, Boisbriand, Qu[eacute]bec J7H 0E2 Canada; 
North America toll-free telephone 833-990-7272 or direct-dial 
telephone 450-990-7272; fax 514-855-8501; email <a href="/cdn-cgi/l/email-protection#f1859995df92839bb1cd90d199839497cc" http: mhirj.com">mhirj.com</a>">thd.crj@mhirj.com</a>; 
website mhirj.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 <a href="/cdn-cgi/l/email-protection#1a267b3a72687f7c27" http: www.archives.gov federal-register cfr ibr-locationsoremailfr.inspection@nara.gov">www.archives.gov/federal-register/cfr/<span class="__cf_email__" data-cfemail="3a535848175655595b4e5355544955485f575b53565c48145354494a5f594e5355547a545b485b145d554c">[email protected]</span></a>"><a href="http://www.archives.gov/federal-register/cfr/ibr-locationsoremailfr.inspection@nara.gov">www.archives.gov/federal-register/cfr/<span class="__cf_email__" data-cfemail="e8818a9ac584878b899c8187869b879a8d858981848e9ac681869b988d8b9c818786a886899a89c68f879e">[email protected]</span></a></a>.

    Issued on August 28, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2024-20244 Filed 9-5-24; 11:15 am]
BILLING CODE 4910-13-P


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