[Federal Register Volume 88, Number 37 (Friday, February 24, 2023)]
[Rules and Regulations]
[Pages 11784-11787]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-03979]



[[Page 11784]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-0161; Project Identifier MCAI-2022-01434-T; 
Amendment 39-22331; AD 2023-03-06]
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 adopting a new airworthiness directive (AD) for all 
Bombardier, Inc., Model BD-700-1A10 and BD-700-1A11 airplanes. 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), and a recent determination that this 
interference can result in unavailable or misleading radio altimeter 
information, adversely affecting the performance of the automatic 
flight control system (AFCS) and resulting in increased flightcrew 
workload during takeoff, approach, and landing below 400 feet above 
ground level (AGL). This AD requires revising the existing airplane 
flight manual (AFM) with new limitations to mitigate identified hazards 
due to 5G C-Band interference as identified by Notices to Air Missions 
(NOTAMs). The FAA is issuing this AD to address the unsafe condition on 
these products.

DATES: This AD is effective March 13, 2023.
    The FAA must receive comments on this AD by April 10, 2023.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     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-2023-0161; 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.

FOR FURTHER INFORMATION CONTACT: Steven Dzierzynski, Aerospace 
Engineer, Avionics and Electrical Systems Section, FAA, New York ACO 
Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 
516-228-7367; email [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this final rule. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2023-0161; Project 
Identifier MCAI-2022-01434-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 Steven 
Dzierzynski, Aerospace Engineer, Avionics and Electrical Systems 
Section, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; telephone 516-228-7367; email [email protected]. 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 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 3.7-3.98 GHz 
frequency band (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 requires 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.
    Since Transport Canada issued AD CF-2021-52, Transport Canada 
evaluated whether additional 5G-related hazards exist in certain 
Bombardier model airplanes. Bombardier has determined that 5G C-Band 
interference can result in unavailable or misleading radio altimeter 
information, adversely affecting the performance of the AFCS as 
follows:
     Erroneous radio altimeter information has the potential to 
cause incorrect gains on approach, flight guidance oscillation, and 
crew over-correction. The flight director uses the glideslope to 
linearize the angular deviation and if the radio altimeter erroneously 
changes to an incorrect value, the resulting pitch command may be 
inadequate, resulting in flight path oscillations.
     Misleading radio altimeter information can adversely 
impact the autothrottle function, resulting in early or late activation 
of the retard mode, leading to an inappropriate level of thrust. This 
may result in a low energy state or longer landing distance. This

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malfunction will increase pilot workload as the crew disconnects the 
autothrottle and overrides the throttle levers.
     In the event of a weight-on-wheels (WOW) signal failure in 
combination with a related Master Minimum Equipment List (MMEL) 
dispatch, interference may result in the radio altimeter deploying the 
two pairs of ground spoilers at heights above 7 feet AGL.
    These effects may lead to increased flightcrew workload and 
adversely affect the safe operation of the airplane during takeoff, 
approach, and landing below 400 feet AGL. Accordingly, Transport Canada 
determined that additional actions are necessary to address the unsafe 
condition and issued AD CF-2022-60, dated November 4, 2022 (Transport 
Canada AD CF-2022-60) (referred to after this as ``the MCAI''), on all 
Bombardier, Inc., Model BD-700-1A10 and BD-700-1A11 airplanes. 
Transport Canada AD CF-2022-60 prohibits dispatch under MMEL item ``WOW 
FAULT (ADVISORY)'' and requires revising the AFM with new limitations 
to prohibit autopilot and autothrottle operation below 400 feet AGL 
when in the presence of 5G C-Band interference as identified by NOTAMs.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2023-0161.

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 
described 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 revising the existing AFM with new limitations to 
prohibit dispatch under MMEL Section 2, CAS Messages, item ``WOW FAULT 
(ADVISORY)'' and to prohibit autopilot and autothrottle operation below 
400 feet AGL when in the presence of 5G C-Band interference as 
identified by NOTAMs.

Interim Action

    The FAA considers this AD interim action. If final action is later 
identified, the FAA might consider further rulemaking then.

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 radio altimeters cannot be relied upon to perform their 
intended function if they experience interference from wireless 
broadband operations in the 5G C-Band. Further, this interference can 
result in unavailable or misleading radio altimeter information, 
adversely affecting the performance of the AFCS, which could lead to 
increased flightcrew workload and adversely affect the safe operation 
of the airplane during takeoff, approach, and landing. The required 
actions to address the unsafe condition must be accomplished within 30 
days, which is shorter than the time necessary to allow for public 
comment and for the FAA to publish a final rule. 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

    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

    The FAA estimates that this AD affects 165 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                        Estimated Costs for AFM Revisions
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                                                                                    Cost per       Cost on U.S.
                          Labor cost                              Parts cost        product         operators
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2 work-hours x $85 per hour = $170...........................              $0             $170          $28,050
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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:

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    (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:

2023-03-06 Bombardier, Inc.: Amendment 39-22331; Docket No. FAA-
2023-0161; Project Identifier MCAI-2022-01434-T.

(a) Effective Date

    This airworthiness directive (AD) is effective March 13, 2023.

(b) Affected ADs

    None.

(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 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), and a recent determination 
that this interference can result in unavailable or misleading radio 
altimeter information, adversely affecting the performance of the 
automatic flight control system (AFCS) and resulting in increased 
flightcrew workload during takeoff, approach, and landing below 400 
feet above ground level. The FAA is issuing this AD to address the 
resulting effects on the performance of the AFCS. The unsafe 
condition, if not addressed, could result in increased flightcrew 
workload and adversely affect the safe operation of the airplane.

(f) Compliance

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

(g) Revision of Existing Airplane Flight Manual (AFM): Master Minimum 
Equipment List (MMEL) Restriction

    Within 30 days after the effective date of this AD, revise the 
Limitations section of the existing AFM to include the information 
specified in figure 1 to paragraph (g) of this AD.

Figure 1 to paragraph (g)--MMEL Restriction
[GRAPHIC] [TIFF OMITTED] TR24FE23.104

(h) Revision of Existing AFM: AFCS

    For airplane serial numbers 9002 through 9998 inclusive, 60001 
through 60060 inclusive, and 60062 through 60064 inclusive: Within 
30 days after the effective date of this AD, revise the Limitations 
section of the existing AFM to include the information specified in 
figure 2 to paragraph (h) of this AD. Using a document with language 
identical to that of figure 2 to paragraph (h) of this AD is 
acceptable for compliance with the requirements of this paragraph.

Figure 2 to paragraph (h): AFM Limitations revision
[GRAPHIC] [TIFF OMITTED] TR24FE23.105

(i) Additional AD Provisions

    The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager, New 
York ACO 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 New York ACO 
Branch, mail it to ATTN: Program Manager, Continuing Operational 
Safety, at the address identified in paragraph (j)(2) of this AD or 
email to: [email protected]. If mailing information, also 
submit information by email. Before using any approved AMOC, notify 
your appropriate principal inspector, or lacking a principal 
inspector, the manager of the responsible Flight Standards Office.
    (2) Previous AMOCs: AMOCs approved for AD 2021-23-12, Amendment 
39-21810 (86 FR 69984, December 9, 2021), providing relief for 
specific radio altimeter installations are approved as AMOCs for the 
provisions of this AD.
    (3) 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, New York ACO 
Branch,

[[Page 11787]]

FAA; or Transport Canada; or Bombardier, Inc.'s Transport Canada 
Design Approval Organization (DAO). If approved by the DAO, the 
approval must include the DAO-authorized signature.

(j) Additional Information

    (1) Refer to Transport Canada AD CF-2022-60, dated November 4, 
2022, for related information. This AD may be found in the AD docket 
at regulations.gov under Docket No. FAA-2023-0161.
    (2) For more information about this AD, contact Steven 
Dzierzynski, Aerospace Engineer, Avionics and Electrical Systems 
Section, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; telephone 516-228-7367; email [email protected].

(k) Material Incorporated by Reference

    None.

    Issued on February 1, 2023.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-03979 Filed 2-22-23; 4:15 pm]
BILLING CODE 4910-13-P


