[Federal Register Volume 88, Number 132 (Wednesday, July 12, 2023)]
[Rules and Regulations]
[Pages 44205-44210]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-14769]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-1406; Project Identifier MCAI-2023-00787-T; 
Amendment 39-22500; AD 2023-13-15]
RIN 2120-AA64


Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2023-03-
06, which applied to all Bombardier, Inc., Model BD-700-1A10 and BD-
700-1A11 airplanes. AD 2023-03-06 required revising the existing 
airplane flight manual (AFM) to incorporate limitations to mitigate 
identified hazards when in the presence of interference from wireless 
broadband operations in the 3.7-3.98 GHz frequency band (5G C-Band) as 
identified by Notices to Air Missions (NOTAMs). Since the FAA issued AD 
2023-03-06, the FAA determined that additional limitations are needed 
due to the continued deployment of new 5G C-Band stations whose signals 
are expected to cover most of the contiguous United States at 
transmission frequencies between 3.7-3.98 GHz. This AD requires 
revising the limitations section of the existing AFM to incorporate 
limitations prohibiting dispatch under a certain master minimum 
equipment list (MMEL) item. The FAA is issuing this AD to address the 
unsafe condition on these products.

DATES: This AD is effective July 27, 2023.
    The FAA must receive comments on this AD by August 28, 2023.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:

[[Page 44206]]

     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-2023-1406; 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, any comments received, and other 
information. The street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Brett Portwood, Continued Operational 
Safety Technical Advisor, COS Program Management Section, Operational 
Safety Branch, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; 
phone: 817-222-5390; email: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written data, views, or arguments 
about this final rule. Send your comments to an address listed under 
ADDRESSES. Include ``Docket No. FAA-2023-1406; Project Identifier MCAI-
2023-00787-T'' 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 
regulations.gov, including any personal information you provide. The 
agency will also post a report summarizing each substantive verbal 
contact received about this final rule.

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 Brett 
Portwood, Continued Operational Safety Technical Advisor, COS Program 
Management Section, Operational Safety Branch, FAA, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 817-222-5390; email: 
[email protected]. Any commentary that the FAA receives that is 
not specifically designated as CBI will be placed in the public docket 
for this rulemaking.

Background

    The FAA issued AD 2021-23-12, Amendment 39-21810 (86 FR 69984, 
December 9, 2021) (AD 2021-23-12), 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 (also 
known as radar) altimeter. AD 2021-23-12 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 2021-23-12 required revising 
the limitations section of the existing AFM to incorporate limitations 
prohibiting certain operations, which require radio altimeter data to 
land in low visibility conditions, when in the presence of 5G C-Band 
interference as identified by NOTAMs. Transport Canada, which is the 
aviation authority for Canada, issued corresponding AD CF-2021-52, 
dated December 24, 2021, to prohibit certain flight operations 
requiring radio altimeter data in U.S. airspace affected by 5G C-Band 
wireless signals.
    Transport Canada subsequently evaluated additional 5G-related 
hazards presented by 5G C-Band interference on Bombardier Model BD-700-
1A10 and BD-700-1A11 airplanes and issued Transport Canada AD CF-2022-
60, dated November 4, 2022 (AD CF-2022-60). AD CF-2022-60 was prompted 
by a determination that 5G C-Band interference can result in 
unavailable or misleading radio altimeter information, adversely 
affecting the performance of the automatic flight control system 
(AFCS). Based on AD CF-2022-60, the FAA issued AD 2023-03-06, Amendment 
39-22331 (88 FR 11784, February 24, 2023) (AD 2023-03-06), for all 
Bombardier, Inc., Model BD-700-1A10 and BD-700-1A11 airplanes. AD 2023-
03-06 required revising the existing AFM to incorporate limitations 
prohibiting dispatch under a certain MMEL item and prohibiting 
autopilot and autothrottle operation below 400 feet above ground level 
(AGL) when in the presence of 5G C-Band interference as identified by 
NOTAMs. The FAA issued AD 2023-03-06 to address the effects of 5G C-
Band interference on the performance of the AFCS, which could result in 
increased flightcrew workload and adversely affect the safe operation 
of the airplane.

Actions Since AD 2023-03-06 Was Issued

    The FAA subsequently determined that NOTAMs identifying the 5G 
environment are no longer practical because of the continued deployment 
of new 5G C-Band base stations, whose signals are expected to cover 
most of the contiguous United States at transmission frequencies 
between 3.7-3.98 GHz. Accordingly, the FAA superseded AD 2021-23-12 and 
issued AD 2023-10-02 (88 FR 34065, May 26, 2023) (AD 2023-10-02). AD 
2023-10-02 prohibits transport and commuter category airplanes from 
performing certain low-visibility landing operations at any airport 
unless they have upgraded their radio altimeters (i.e., are ``radio 
altimeter tolerant'').
    In addition, Transport Canada superseded AD CF-2022-60 and issued 
Transport Canada AD CF-2023-44, dated June 26, 2023 (Transport Canada 
AD CF-2023-44) (also referred to after this as ``the MCAI''), for all 
Model BD-700-1A10 and BD-700-1A11 airplanes. Transport Canada 
determined that although anomalies with the AFCS and autothrottle 
remain possible in the presence of harmful interference, there are 
sufficient mitigating factors such that Transport Canada no longer 
considers this an unsafe condition. As a result, the MCAI removes the 
AFM limitation on the AFCS and autothrottle. The MCAI also replaces the 
prohibition of dispatch under a certain MMEL item at airports 
identified by NOTAM with the same prohibition, for non-radio altimeter 
tolerant airplanes, at all airports in the contiguous United States. 
For radio altimeter tolerant airplanes, the MCAI does not prohibit 
dispatch under the MMEL item at 5G C-Band mitigated airports (CMAs) as 
identified in an FAA Domestic Notice. Transport Canada issued the MCAI 
to prevent dispatch under MMEL item ``WOW

[[Page 44207]]

FAULT (ADVISORY)'' which, in combination with 5G interference and a 
weight-on-wheels (WOW) signal failure, could result in the radio 
altimeter deploying the two pairs of ground spoilers at heights above 7 
feet AGL. This may lead to increased flightcrew workload and adversely 
affect the safe operation of the airplane.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2023-1406.

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 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, before further flight, revising the AFM to 
incorporate limitations prohibiting dispatch with use of a certain MMEL 
item at all airports for non-radio altimeter tolerant airplanes. For 
radio altimeter tolerant airplanes, the prohibited operations are 
allowed at 5G CMAs as identified in an FAA Domestic Notice.

Interim Action

    The FAA considers that this AD is an interim action. Once the 
Technical Standard Order (TSO) standard for radio altimeters is 
established, which will follow the existing international technical 
consensus on the establishment of the minimum operational performance 
standards (MOPS), the FAA anticipates that the MOPS will be 
incorporated into the TSO. Once a new radio altimeter TSO is developed, 
approved, and available, the FAA might consider additional rulemaking.

Justification for Immediate Adoption and Determination of the Effective 
Date

    Section 553(b)(3)(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.
    An unsafe condition exists that requires the immediate adoption of 
this AD without providing an opportunity for public comments prior to 
adoption. The FAA has found that the risk to the flying public 
justifies forgoing notice and comment prior to adoption of this rule 
because dispatch under MMEL item ``WOW FAULT (ADVISORY),'' in 
combination with 5G interference and a WOW signal failure, could result 
in the radio altimeter deploying the two pairs of ground spoilers at 
heights above 7 feet AGL. This may lead to increased flightcrew 
workload and loss of continued safe flight and landing. To address this 
unsafe condition, the actions required by this AD must be accomplished 
before further flight. The FAA based this compliance time on the 
changes to the 5G C-Band environment beginning on July 1, 2023. These 
changes include increased wireless broadband deployment and 
transmissions closer to the parameters authorized by the FCC. 
Accordingly, notice and opportunity for prior public comment are 
impracticable and contrary to the public interest pursuant to 5 U.S.C. 
553(b)(3)(B).
    In addition, 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, 
for the same reasons the FAA found good cause to forgo notice and 
comment.

Regulatory Flexibility Act (RFA)

    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 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

    The FAA estimates that this AD affects 165 airplanes of U.S. 
registry of U.S. registry. The FAA estimates the following costs to 
comply with this AD:
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    \1\ The labor rate of $85 per hour is the average wage rate for 
an aviation mechanic.
    \2\ The estimated cost for this revision does not constitute a 
significant economic impact (even for small entities) because $85 is 
a minimal cost compared to the regular costs of maintaining and 
operating a Model BD-700-1A10 or BD-700-1A11 transport category 
airplane.

                                      Estimated Costs for Required Actions
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                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
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AFM revision..........................  1 work-hour x $85 \1\                 $0             $85     \2\ $14,025
                                         per hour = $85.
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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 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

    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.

[[Page 44208]]

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:
0
a. Removing Airworthiness Directive 2023-03-06, Amendment 39-22331 (88 
FR 11784, February 24, 2023); and
0
b. Adding the following new airworthiness directive:

2023-13-15 Bombardier, Inc.: Amendment 39-22500; Docket No. FAA-
2023-1406; Project Identifier MCAI-2023-00787-T.

(a) Effective Date

    This airworthiness directive (AD) is effective July 27, 2023.

(b) Affected ADs

    This AD replaces AD 2023-03-06, Amendment 39-22331 (88 FR 11784, 
February 24, 2023) (AD 2023-03-06).

(c) Applicability

    This AD applies to all Bombardier, Inc., Model BD-700-1A10 and 
BD-700-1A11 airplanes, certificated in any category.

(d) Subject

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

(e) Reason

    This AD 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 
3.7-3.98 GHz frequency band (5G C-Band), and a recent determination 
that this interference may affect other airplane systems using radio 
altimeter data, including the ground spoiler deployment system. The 
FAA is issuing this AD to address inadvertent ground spoiler 
deployment in flight that could lead to increased flightcrew 
workload and loss of continued safe flight and landing.

(f) Compliance

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

(g) Definitions

    (1) For purposes of this AD, a ``5G C-Band mitigated airport'' 
(5G CMA) is an airport at which the telecommunications companies 
have agreed to voluntarily limit their 5G deployment at the request 
of the FAA, as identified by an FAA Domestic Notice.
    (2) 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)(2)(i) and 
(ii) of this AD, using a method approved by the FAA.
    (i) 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)(2)(i) of this AD.
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Figure 1 to Paragraph (g)(2)(i)--Fundamental Effective Isotropic PSD at 
Outside Interface of Aircraft Antenna
[GRAPHIC] [TIFF OMITTED] TR12JY23.027

    (ii) 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)(ii) of this AD.

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

[[Page 44209]]

[GRAPHIC] [TIFF OMITTED] TR12JY23.028

    (3) For purposes of this AD, a ``non-radio altimeter tolerant 
airplane'' is one for which the radio altimeter, as installed, does 
not demonstrate the tolerances specified in paragraphs (g)(2)(i) and 
(ii) of this AD.

(h) Airplane Flight Manual (AFM) Revision for Non-Radio Altimeter 
Tolerant Airplanes: MMEL Restriction

    For non-radio altimeter tolerant airplanes, before further 
flight, revise the Limitations Section of the existing AFM to 
include the information specified in figure 3 to paragraph (h) of 
this AD. This may be done by inserting a copy of figure 3 to 
paragraph (h) of this AD into the existing AFM.

Figure 3 to Paragraph (h)--AFM Revision for Non-Radio Altimeter 
Tolerant Airplanes: MMEL Restriction
[GRAPHIC] [TIFF OMITTED] TR12JY23.029

(i) AFM Revision for Radio Altimeter Tolerant Airplanes: MMEL 
Restriction

    For radio altimeter tolerant airplanes, before further flight, 
revise the Limitations Section of the existing AFM to include the 
information specified in figure 4 to paragraph (i) of this AD. This 
may be done by inserting a copy of figure 4 to paragraph (i) of this 
AD into the existing AFM.

Figure 4 to Paragraph (i)--AFM Revision for Radio Altimeter Tolerant 
Airplanes: MMEL Restriction

[[Page 44210]]

[GRAPHIC] [TIFF OMITTED] TR12JY23.030

(j) Additional AD Provisions

    The following provisions also apply to this AD:
    (1) The Manager, Operational Safety 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 Operational Safety Branch, send it to the 
attention of the person identified in paragraph (k)(2) of this AD. 
Information may be emailed to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the responsible Flight Standards Office.

(k) Related Information

    (1) Refer to Transport Canada AD CF-2023-44, dated June 26, 
2023, for related information. This Transport Canada AD may be found 
in the AD docket at regulations.gov under Docket No. FAA-2023-1406.
    (2) For more information about this AD, contact Brett Portwood, 
Continued Operational Safety Technical Advisor, COS Program 
Management Section, Operational Safety Branch, FAA, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 817-222-5390; email: 
[email protected].

(l) Material Incorporated by Reference

    None.

    Issued on July 3, 2023.
Michael Linegang,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-14769 Filed 7-7-23; 4:15 pm]
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