[Federal Register Volume 87, Number 20 (Monday, January 31, 2022)]
[Rules and Regulations]
[Pages 4787-4797]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-01995]



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 Rules and Regulations
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  Federal Register / Vol. 87, No. 20 / Monday, January 31, 2022 / Rules 
and Regulations  

[[Page 4787]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0017; Project Identifier AD-2022-00058-T; 
Amendment 39-21937; AD 2022-03-20]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company 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 
The Boeing Company Model 737-8, 737-9, and 737-8200 airplanes. 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, during takeoffs and 
landings, as a result of this interference, certain airplane systems 
may not properly function, resulting in longer than normal landing or 
rejected takeoff distances due to the effect on thrust reverser 
deployment, spoilers, speedbrake deployment, and increased idle thrust, 
regardless of the approach type or weather. This AD requires revising 
the limitations and operating procedures sections of the existing 
airplane flight manual (AFM) to incorporate limitations prohibiting the 
use of certain minimum equipment list (MEL) items, and to incorporate 
operating procedures for calculating takeoff and landing distances, 
when in the presence of 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 January 31, 2022.
    The FAA must receive comments on this AD by March 17, 2022.

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 https://www.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.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2022-0017; 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 the 
Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Dean Thompson, Senior Aerospace 
Engineer, Systems and Equipment Section, FAA, Seattle ACO Branch, 2200 
South 216th St., Des Moines, WA 98198; phone and fax: 206-231-3165; 
email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    In March 2020, the United States Federal Communications Commission 
(FCC) adopted final rules authorizing flexible use of the 3.7-3.98 GHz 
band for next generation services, including 5G and other advanced 
spectrum-based services.\1\ Pursuant to these rules, C-Band wireless 
broadband deployment was permitted to occur in phases with the 
opportunity for operations in the lower 0.1 GHz of the band (3.7-3.8 
GHz) in certain markets beginning on January 19, 2022. This AD refers 
to ``5G C-Band'' interference, but wireless broadband technologies, 
other than 5G, may use the same frequency band.\2\ These other uses of 
the same frequency band are within the scope of this AD since they 
would introduce the same risk of radio altimeter interference as 5G C-
Band.
---------------------------------------------------------------------------

    \1\ The FCC's rules did not make C-Band wireless broadband 
available in Alaska, Hawaii, and the U.S. Territories.
    \2\ The regulatory text of the AD uses the term ``5G C-Band'' 
which, for purposes of this AD, has the same meaning as ``5G'', ``C-
Band'' and ``3.7-3.98 GHz.''
---------------------------------------------------------------------------

    The radio altimeter is an important aircraft instrument, and its 
intended function is to provide direct height-above-terrain/water 
information to a variety of aircraft systems. Commercial aviation radio 
altimeters operate in the 4.2-4.4 GHz band, which is separated by 0.22 
GHz from the C-Band telecommunication systems in the 3.7-3.98 GHz band. 
The radio altimeter is more precise than a barometric altimeter and for 
that reason is used where aircraft height over the ground needs to be 
precisely measured, such as autoland, manual landings, or other low 
altitude operations. The receiver on the radio altimeter is typically 
highly accurate, however it may deliver erroneous results in the 
presence of out-of-band radio frequency emissions from other frequency 
bands. The radio altimeter must detect faint signals reflected off the 
ground to measure altitude, in a manner similar to radar. Out-of-band 
signals could significantly degrade radio altimeter functions during 
critical phases of flight, if the altimeter is unable to sufficiently 
reject those signals.
    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 5G C-Band 
interference on all transport and commuter category airplanes equipped 
with a radio (also known as radar) altimeter. 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 NOTAM. The FAA 
issued AD 2021-23-12 because radio altimeter anomalies that are 
undetected by the automation or pilot, particularly close to the ground 
(e.g., landing flare), could lead to loss of continued safe flight and 
landing.
    Since the FAA issued AD 2021-23-12, Boeing has continued to 
evaluate potential 5G C-Band interference on

[[Page 4788]]

aircraft systems that rely on radio altimeter inputs. Boeing issued 
Boeing Multi Operator Message MOM-MOM-22-0016-01B(R1), dated January 
16, 2022, and Boeing Flight Crew Operations Manual Bulletin TBC-26, 
``Radio Altimeter Anomalies due to 5G C-Band Wireless Broadband 
Interference in the United States,'' dated January 17, 2022.
    Based on Boeing's data, the FAA identified an additional hazard 
presented by 5G C-Band interference on The Boeing Company 737-8, 737-9, 
and 737-8200 airplanes. The FAA determined anomalies due to 5G C-Band 
interference may affect multiple other airplane systems using radio 
altimeter data, regardless of the approach type or weather. These 
anomalies may not be evident until very low altitudes. Impacted systems 
include, but are not limited to: Autopilot flight director system; 
autothrottle system; engines; thrust reversers; flight controls; flight 
instruments; traffic alert and collision avoidance system (TCAS); 
ground proximity warning system (GPWS); and configuration warnings.
    As a result of erroneous radio altimeter data provided to these 
systems in the event of 5G C-Band interference, takeoff and landing 
performance can be adversely impacted. This may have multiple effects, 
including:
     Autothrottle may remain in speed (SPD) mode and may 
increase thrust to maintain speed during flare instead of reducing the 
thrust to IDLE at 27 feet radio altitude (RA) or may reduce thrust to 
IDLE prematurely.
     Thrust reversers may not deploy during rejected takeoff or 
landing roll.
     Engines may be at higher idle during rejected takeoff or 
remain at approach idle after touchdown.
     Automatic speedbrake may not deploy after touchdown during 
the landing roll.
     SPEEDBRAKE EXTENDED light may not be available or may 
illuminate erroneously during the landing roll.
     SPEEDBRAKE time critical visual and aural warnings may not 
be available during the landing roll.
     Spoilers may be limited to their maximum in-flight 
position during manual deployment after rejected takeoff or touchdown 
during the landing roll.
     Landing Attitude Modifier may be erroneous.
     Other simultaneous flight deck effects associated with the 
5G C-Band interference could increase pilot workload.
    As a result of these effects, lack of thrust reverser and 
speedbrake deployment, limited spoiler extension, and increased idle 
thrust may occur; and brakes may be the only means to slow the 
airplane. Therefore, the presence of 5G C-Band interference can result 
in degraded deceleration performance, subsequently resulting in longer 
than normal landing or rejected takeoff distances, which could lead to 
a runway excursion. This is an unsafe condition.
    The severity of the hazard created by a lack of thrust reverser and 
speedbrake deployment, limited spoiler extension, and by increased idle 
thrust, increases when the runway is contaminated with frozen or liquid 
precipitation. The FAA categorizes runway surface conditions with codes 
from 6 through 0, with 6 being a dry runway and therefore no 
detrimental effect on braking, and a code of 0 denoting surface 
conditions, such as wet ice, in which braking may not be effective.
    This AD mandates procedures for operators to account for this 
longer than normal landing or rejected takeoff distances, for all 
runway conditions, in the presence of 5G C-Band interference as 
identified by NOTAM. It prohibits operators from dispatching or 
releasing airplanes to or from affected airports when certain braking 
and anti-skid functions on the airplane are inoperable. It also 
prohibits operators from dispatch or release to, or takeoff or landing 
on, runways with condition codes 1 and 0.
    The FAA is issuing this AD to address the unsafe condition on these 
products.

FAA's Determination

    The FAA is issuing this AD because the agency has determined the 
unsafe condition described previously is likely to exist or develop in 
other products of the same type design.

AD Requirements

    This AD requires revising the limitations and operating procedures 
sections of the existing AFM to incorporate limitations prohibiting the 
use of certain MEL items, and to incorporate operating procedures for 
calculating takeoff and landing distances, when in the presence of 5G 
C-Band interference as identified by NOTAMs.

Compliance With AFM Revisions

    Section 91.9 prohibits any person from operating a civil aircraft 
without complying with the operating limitations specified in the AFM. 
FAA regulations also require operators to furnish pilots with any 
changes to the AFM (14 CFR 121.137) and pilots in command to be 
familiar with the AFM (14 CFR 91.505).

Interim Action

    The FAA considers this AD to be an interim action. If final action 
is later identified, the FAA might consider further 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 during takeoffs and landings, as a result of 5G C-Band 
interference, certain airplane systems may not properly function, 
resulting in longer than normal landing or rejected takeoff distances 
due to the effect on thrust reverser deployment, spoilers, speedbrake 
deployment, and increased idle thrust, regardless of the approach type 
or weather. This could result in a runway excursion. The urgency is 
based on C-Band wireless broadband deployment, which was expected to 
occur in phases with operations beginning on January 19, 2022. 
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.

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-2022-0017 and Project Identifier AD-
2022-00058-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

[[Page 4789]]

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 
https://www.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 Dean 
Thompson, Senior Aerospace Engineer, Systems and Equipment Section, 
FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; 
phone and fax: 206-231-3165; 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.

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 notice and comment, 
RFA analysis is not required.

Costs of Compliance

    The FAA estimates that this AD affects 177 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
               Action                         Labor cost            Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
AFM revision.......................  1 work-hour x $85 per hour               $0             $85         $15,045
                                      = $85.
----------------------------------------------------------------------------------------------------------------

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.

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:

2022-03-20 The Boeing Company: Amendment 39-21937 ; Docket No. FAA-
2022-0017; Project Identifier AD-2022-00058-T.

(a) Effective Date

    This airworthiness directive (AD) is effective January 31, 2022.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-8, 737-9, and 
737-8200 airplanes, certificated in any category.

(d) Subject

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

(e) Unsafe Condition

    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 determination that, 
during takeoffs and landings, as a result of this interference, 
certain airplane systems may not properly function, resulting in 
longer than normal landing or rejected takeoff distances due to the 
effect on thrust reverser deployment, spoilers, speedbrake 
deployment, and increased idle thrust, regardless of the approach 
type or weather. The FAA is issuing this AD to address degraded 
deceleration performance, which could lead to a runway excursion.

(f) Compliance

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

(g) Definitions

    Runway condition codes are defined in figure 1 to paragraph (g) 
of this AD.

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[GRAPHIC] [TIFF OMITTED] TR31JA22.003

(h) Airplane Flight Manual (AFM) Revision

    (1) Within 2 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)(1) of this AD. 
This may be done by inserting a copy of figure 2 to paragraph (h)(1) 
of this AD into the existing AFM.
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[GRAPHIC] [TIFF OMITTED] TR31JA22.004

    (2) Within 2 days after the effective date of this AD: Revise 
the Operating Procedures Section of the existing AFM to include the 
information specified in figure 3 to paragraph (h)(2) of this AD. 
This may be done by inserting a copy of figure 3 to paragraph (h)(2) 
of this AD into the existing AFM.

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[GRAPHIC] [TIFF OMITTED] TR31JA22.010

    Note 1 to paragraph (h): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Multi Operator Message 
MOM-MOM-22-0016-01B(R1), dated January 16, 2022, and Boeing Flight 
Crew Operations Manual Bulletin TBC-26, ``Radio Altimeter Anomalies 
due to 5G C-Band Wireless Broadband Interference in the United 
States,'' dated January 17, 2022.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle 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 responsible Flight Standards Office, 
as appropriate. If sending information directly to the manager of 
the certification office, send it to the attention of the person 
identified in paragraph (j)(1) 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.
    (3) 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.

(j) Related Information

    (1) For more information about this AD, contact Dean Thompson, 
Senior Aerospace Engineer, Systems and Equipment Section, FAA, 
Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; 
phone and fax: 206-231-3165; email: [email protected].
    (2) For service information identified in this AD that is not 
incorporated by reference, contact Boeing Commercial Airplanes, 
Attention: Contractual & Data Services (C&DS), 2600 Westminster 
Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone 562-797-
1717; internet https://www.myboeingfleet.com.

(k) Material Incorporated by Reference

    None.

    Issued on January 26, 2022.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2022-01995 Filed 1-27-22; 4:15 pm]
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