[Federal Register Volume 87, Number 37 (Thursday, February 24, 2022)]
[Rules and Regulations]
[Pages 10299-10305]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-03967]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0142; Project Identifier AD-2022-00071-T; 
Amendment 39-21955; AD 2022-05-04]
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 737-100, -200, -200C, -300, -400, -500, -600, 
-700,

[[Page 10300]]

-700C, -800, -900, and -900ER series airplanes, except for Model 737-
200 and -200C series airplanes equipped with a certain flight control 
system. 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 approach, landings, and go-arounds, as a result of this 
interference, certain airplane systems may not properly function, 
resulting in increased flightcrew workload while on approach with the 
flight director, autothrottle, or autopilot engaged, which could result 
in reduced ability of the flightcrew to maintain safe flight and 
landing of the airplane. This AD requires revising the limitations and 
operating procedures sections of the existing airplane flight manual 
(AFM) to incorporate specific operating procedures for instrument 
landing system (ILS) approaches, speedbrake deployment, go-arounds, and 
missed approaches, 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 February 24, 2022.
    The FAA must receive comments on this AD by April 11, 2022.

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 https://www.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.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2022-0142; 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: For Model 737-100, -200, -200C, -300, 
-400, and -500 series airplanes, contact Jeffrey W. Palmer, Aerospace 
Engineer, Systems and Equipment Section, FAA, Los Angeles ACO Branch, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5351; 
email: <a href="/cdn-cgi/l/email-protection#d2b8b7b4b4a0b7abfca5fca2b3bebfb7a092b4b3b3fcb5bda4"><span class="__cf_email__" data-cfemail="402a2526263225396e376e30212c2d2532002621216e272f36">[email protected]</span></a>. For Model 737-600, -700, -700C, -800, 
-900, and -900ER series airplanes, 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: <a href="/cdn-cgi/l/email-protection#e58180848bcb97cb918d8a8895968a8ba5838484cb828a93"><span class="__cf_email__" data-cfemail="aecacbcfc080dc80dac6c1c3deddc1c0eec8cfcf80c9c1d8">[email protected]</span></a>.

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.
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    \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.''
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    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 aircraft systems that rely 
on radio altimeter inputs. Boeing issued Boeing Multi Operator Message 
MOM-MOM-22-0041-01B(R1), dated February 1, 2022; Boeing Multi Operator 
Message MOM-MOM-22-0017-01B(R2), dated February 1, 2022; Boeing Flight 
Crew Operations Manual Bulletin TBCN-28, ``Radio Altimeter Anomalies 
due to 5G C-Band Wireless Broadband Interference in the United 
States,'' dated January 17, 2022; Boeing Flight Crew Operations Manual 
Bulletin TBC-30 R1, ``Radio Altimeter Anomalies due to 5G C-Band 
Wireless Broadband Interference in the United States,'' dated February 
4, 2022; Boeing Flight Crew Operations Manual Bulletin TBCE-32 R1, 
``Radio Altimeter Anomalies due to 5G C-Band Wireless Broadband 
Interference in the United States,'' dated February 4, 2022; and Boeing 
Flight Crew Operations Manual Bulletin TBC 117 R1, ``Radio Altimeter 
Anomalies due to 5G C-Band Wireless Broadband Interference in the 
United States,'' dated February 4, 2022; for Model 737-200, -200C, -
300, -400, -500, -600, -700, -700C, -800, -900, and -900ER series 
airplanes.
    Based on Boeing's data, the FAA identified an additional hazard 
presented by 5G C-Band interference on The Boeing Company Model 737-
100, -200, -200C, -300, -400, -500, -600, -700, -700C, -800, -900, and 
-900ER series airplanes, except for Model 737-200 and -200C series 
airplanes equipped with an SP-77 flight control system. The SP-77 
flight control system

[[Page 10301]]

did not include autoland or flare mode, which, as described below, are 
affected by 5G C-Band interference. 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; flight controls; flight instruments; traffic alert 
and collision avoidance system (TCAS); ground proximity warning system 
(GPWS); and configuration warnings.
    The effects on these impacted systems include:
    <bullet> Autopilot Flight Director System: NO AUTOLAND autopilot 
status annunciation may be shown; autopilot may not engage; autopilot 
disconnect may occur during ILS/GLS approaches; the flight directors 
may provide erroneous guidance during ILS approaches; runway alignment 
may not occur or may activate earlier or later than expected; flare may 
not occur; FLARE mode can be erroneously annunciated on the FMA (flight 
mode annunciation); or go-around mode may not be available.
    <bullet> Autothrottle System: Autothrottle can remain in SPD 
(speed) mode and may advance to maintain speed during flare instead of 
retard to IDLE; or autothrottle may retard to idle prematurely in the 
flare.
    <bullet> Flight Controls: Automatic speedbrake deployment may not 
occur after touchdown (for Model -600, -700, -700C, -800, -900, and -
900ER series airplanes); or SPEEDBRAKES EXT or SPEED BRAKE Caution 
message may not be available or may illuminate erroneously.
    <bullet> Flight Instruments: The radio altimeter indication may not 
be shown; the RADIO minimums indications (flashing or turning amber) 
may not be shown or may be erroneous; the rising runway symbol may not 
be shown; the localizer deviation alert amber scale and flashing 
pointer may not be shown (deviation indications are still available); 
or the glideslope deviation alert amber scale and flashing pointer may 
not be shown (deviation indications are still available).
    <bullet> TCAS: TCAS alerts may not be available (TCAS alerts that 
do occur will be valid); or TCAS inhibits for resolution advisories may 
be erroneous.
    <bullet> GPWS: GPWS alerts may not be available or may be erroneous 
(although look-ahead terrain alerting remains available); radio 
altimeter-based altitude and minimums aural callouts during approach 
may not be available or erroneous; or windshear detection systems 
(predictive and reactive) may be inoperative.
    <bullet> Configuration Warnings: Erroneous illumination of the red 
landing gear indicator lights may occur; erroneous steady landing gear 
warning horn may occur; or radio altitude based alerts may not be 
available or may be erroneous.
    <bullet> Considerations for Dispatch: For Model 737-600, -700, -
700C, -800, -900, and -900ER series airplanes, adjust operational (time 
of arrival) landing distance for manual speedbrakes. For Model 737-100, 
-200, -200C, -300, -400, and -500 series airplanes, no impacts on 
dispatch landing performance calculations.
    <bullet> Other simultaneous flight deck effects associated with the 
5G C-Band interference could increase pilot workload.
    These effects may cause erroneous indications and annunciations, as 
well as conflicting information, to be provided to the flightcrew 
during a critical phase of flight. There may also be a lack of cues 
present to elicit prompt go-around or recovery initiation. These 
effects could lead to reduced ability of the flightcrew to maintain 
safe flight and landing of the airplane and is an unsafe condition. 
Thus, the FAA has determined that prompt identification of a potential 
problem and initiation of a go-around are required to ensure the 
capability for continued safe flight and landing.
    To address this unsafe condition, this AD mandates procedures for 
operators to incorporate specific operating procedures for landing 
distance calculations, ILS (and GLS if installed) approaches, 
speedbrake deployment, go-arounds, and missed approaches, when in the 
presence of 5G C-Band interference as identified by NOTAMs. The 
operating procedures mandated by this AD require the flightcrew to 
execute a go-around if they encounter certain conditions during ILS 
approaches, and prohibit them from using certain affected systems 
during the go-around until reaching a safe altitude.
    Finally, the FAA notes that AD 2021-23-12 remains in effect and 
thus prohibits certain ILS approaches. Thus, this AD addresses 
procedures applicable only to those ILS approaches not prohibited by AD 
2021-23-12.
    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 specific operating 
procedures for ILS and GLS (if installed) approaches, speedbrake 
deployment, go-arounds, and missed approaches, 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 the FAA determined 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, and a determination 
that, during approach, landings, and go-arounds, as a result of this 
interference, certain airplane systems may not properly function, 
resulting in increased flightcrew workload while on approach with the 
flight director, autothrottle, or autopilot engaged. This increased 
flightcrew workload could lead to reduced ability of the flightcrew to 
maintain safe flight and landing of the

[[Page 10302]]

airplane. The urgency is based on the hazard presented by 5G C-Band 
interference, and on C-Band wireless broadband deployment, which began 
in phases with operations 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-2022-0142 and Project Identifier AD-
2022-00071-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 
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 for Model 737-100, -200, 
-200C, -300, -400, and -500 series airplanes should be sent to Jeffrey 
W. Palmer, Aerospace Engineer, Systems and Equipment Section, FAA, Los 
Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; 
phone: 562-627-5351; email: <a href="/cdn-cgi/l/email-protection#264c43404054435f08510856474a4b43546640474708414950"><span class="__cf_email__" data-cfemail="e08a858686928599ce97ce90818c8d8592a0868181ce878f96">[email protected]</span></a>. Submissions 
containing CBI for Model 737-600, -700, -700C, -800, -900, and -900ER 
series airplanes 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: <a href="/cdn-cgi/l/email-protection#eb8f8e8a85c599c59f8384869b988485ab8d8a8ac58c849d"><span class="__cf_email__" data-cfemail="b5d1d0d4db9bc79bc1dddad8c5c6dadbf5d3d4d49bd2dac3">[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.

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 2,442 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                 $0             $85        $207,570
                                         hour = $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:

2022-05-04 The Boeing Company: Amendment 39-21955; Docket No. FAA-
2022-0142; Project Identifier AD-2022-00071-T.

(a) Effective Date

    This airworthiness directive (AD) is effective February 24, 
2022.

[[Page 10303]]

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737-100, -200, -
200C, -300, -400, -500, -600, -700, -700C, -800, -900, and -900ER 
series airplanes, certificated in any category, except for Model 
737-200 and -200C series airplanes equipped with an SP-77 flight 
control system.

(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 approach, landings, and go-arounds, as a result of this 
interference, certain airplane systems may not properly function, 
resulting in increased flightcrew workload while on approach with 
the flight director, autothrottle, or autopilot engaged. The FAA is 
issuing this AD to address 5G C-Band interference that could result 
in increased flightcrew workload and could lead to reduced ability 
of the flightcrew to maintain safe flight and landing of the 
airplane.

(f) Compliance

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

(g) 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 1 to paragraph (g)(1) of this AD. 
This may be done by inserting a copy of figure 1 to paragraph (g)(1) 
of this AD into the Limitations Section of the existing AFM.
BILLING CODE 4910-13-P
[GRAPHIC] [TIFF OMITTED] TR24FE22.043

    (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 2 to paragraph (g)(2) of this AD or 
figure 3 to paragraph (g)(2) of this AD, as applicable. This may be 
done by inserting a copy of figure 2 to paragraph (g)(2) of this AD 
or figure 3 to paragraph (g)(2) of this AD, as applicable, into the 
Operating Procedures Section of the existing AFM.

[[Page 10304]]

[GRAPHIC] [TIFF OMITTED] TR24FE22.044

[GRAPHIC] [TIFF OMITTED] TR24FE22.045


[[Page 10305]]


    Note 1 to paragraph (g)(2): Guidance for accomplishing the 
actions required by paragraph (g)(2) of this AD can be found in 
Boeing Multi Operator Message MOM-MOM-22-0041-01B(R1), dated 
February 1, 2022; Boeing Multi Operator Message MOM-MOM-22-0017-
01B(R2), dated February 1, 2022; Boeing Flight Crew Operations 
Manual Bulletin TBCN-28, ``Radio Altimeter Anomalies due to 5G C-
Band Wireless Broadband Interference in the United States,'' dated 
January 17, 2022; Boeing Flight Crew Operations Manual Bulletin TBC-
30 R1, ``Radio Altimeter Anomalies due to 5G C-Band Wireless 
Broadband Interference in the United States,'' dated February 4, 
2022; Boeing Flight Crew Operations Manual Bulletin TBCE-32 R1, 
``Radio Altimeter Anomalies due to 5G C-Band Wireless Broadband 
Interference in the United States,'' dated February 4, 2022; and 
Boeing Flight Crew Operations Manual Bulletin TBC-117 R1, ``Radio 
Altimeter Anomalies due to 5G C-Band Wireless Broadband Interference 
in the United States,'' dated February 4, 2022.

(h) Alternative Methods of Compliance (AMOCs)

    (1) For Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes: The Manager, Los Angeles 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 (i)(1) of this AD. Information 
may be emailed to: <a href="/cdn-cgi/l/email-protection#320b1f737c7f1f7e7373717d1f737f7d711f6057434757414641725453531c555d44"><span class="__cf_email__" data-cfemail="93aabed2dddebedfd2d2d0dcbed2dedcd0bec1f6e2e6f6e0e7e0d3f5f2f2bdf4fce5">[email protected]</span></a>. For Model 737-
600, -700, -700C, -800, -900, and -900ER series airplanes: 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 (i)(2) of this AD. Information may be 
emailed to: <a href="/cdn-cgi/l/email-protection#447d69050a0969172125303028216905070b6905090b07691621353121373037042225256a232b32"><span class="__cf_email__" data-cfemail="b58c98f4fbf898e6d0d4c1c1d9d098f4f6fa98f4f8faf698e7d0c4c0d0c6c1c6f5d3d4d49bd2dac3">[email protected]</span></a>.
    (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.

(i) Related Information

    (1) For more information about this AD for Model 737-100, -200, 
-200C, -300, -400, and -500 series airplanes, contact Jeffrey W. 
Palmer, Aerospace Engineer, Systems and Equipment Section, FAA, Los 
Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-
4137; phone: 562-627-5351; email: <a href="/cdn-cgi/l/email-protection#8be1eeededf9eef2a5fca5fbeae7e6eef9cbedeaeaa5ece4fd"><span class="__cf_email__" data-cfemail="aec4cbc8c8dccbd780d980decfc2c3cbdceec8cfcf80c9c1d8">[email protected]</span></a>.
    (2) For more information about this AD for Model 737-600, -700, 
-700C, -800, -900, and -900ER series airplanes, 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: <a href="/cdn-cgi/l/email-protection#c2a6a7a3acecb0ecb6aaadafb2b1adac82a4a3a3eca5adb4"><span class="__cf_email__" data-cfemail="8febeaeee1a1fda1fbe7e0e2fffce0e1cfe9eeeea1e8e0f9">[email protected]</span></a>.
    (3) 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.

(j) Material Incorporated by Reference

    None.

    Issued on February 16, 2022.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2022-03967 Filed 2-22-22; 11:15 am]
BILLING CODE 4910-13-C


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