Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 88, Number 118 (Wednesday, June 21, 2023)]
[Rules and Regulations]
[Pages 39996-40003]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-13151]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-0921; Project Identifier AD-2022-01430-T; 
Amendment 39-22471; AD 2023-12-13]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2022-05-
04, which applied to all 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 a certain flight control system. AD 2022-05-04 required 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 
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 2022-05-04, the FAA determined that 
additional limitations are needed due to 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. This AD requires revising the limitations and operating 
procedures sections of the existing AFM to incorporate specific 
operating procedures for ILS approaches, speedbrake deployment, go-
arounds, and missed approaches, due to the presence of 5G C-Band 
interference. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective June 21, 2023.

ADDRESSES: AD Docket: You may examine the AD docket at regulations.gov 
under Docket No. FAA-2023-0921; 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 address for Docket Operations is 
U.S. Department of Transportation, Docket Operations, M-30, West 
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, 
Washington, DC 20590.

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: 

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2022-05-04, Amendment 39-21955 (87 FR 
10299, February 24, 2022) (AD 2022-05-04). AD 2022-05-04 applied to all 
The Boeing Company (Boeing) 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 a certain 
flight control system. The NPRM published in the Federal Register on 
May 3, 2023 (88 FR 27725). The NPRM was prompted by a determination 
that radio altimeters cannot be relied upon to perform their intended 
function if they experience 5G C-Band interference, 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.
    In the NPRM, the FAA proposed to retain the AFM revisions required 
by AD 2022-05-04 until June 30, 2023. On or before June 30, 2023, the 
FAA proposed to require replacing those AFM revisions with limitations 
requiring the same procedures for dispatch or release to airports, and 
approach, landing, and go-around on runways, at all airports for non-
radio altimeter tolerant airplanes. For radio altimeter tolerant 
airplanes, the FAA proposed to allow the procedures at 5G CMAs as 
identified in an FAA Domestic Notice. The FAA proposed 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.

Discussion of Final Airworthiness Directive

Comments

    The FAA provided the public with an opportunity to comment on the 
proposed AD and received comments from seven commenters. The following 
presents the comments received on the NPRM and the FAA's response to 
each comment.

Support for NPRM

    Boeing, the Air Line Pilots Association, International (ALPA), and 
an individual supported the NPRM without change.
    The supportive comments from ALPA included additional viewpoints 
without a suggestion specific to the AD or a request the FAA can act 
on. These comments are outside the scope of this AD.

Request To Clarify AD Issue Dates

    Comment summary: FlyPersia Airlines commented that the issue dates 
referenced for AD 2022-23-12 and AD 2022-05-04 in the background 
section of the proposed AD are incorrect. The commenter stated that 
where ``The FAA issued AD 2022-23-12 (86 FR 69984, December 9, 2021)'' 
is stated, the correct date should be December 7, 2021; in same section 
where the proposed AD specifies ``AD 2022-05-04 (87 FR 10299, February 
24, 2022),'' the commenter stated the correct date should be February 
16, 2022.
    FAA response: The dates quoted by the commenter are within the 
parenthetical citations for referencing documents published in the 
Federal Register by volume, page, and publication date. These dates 
represent the dates each AD published in the Federal Register. The 
December 7, 2021, and February 24, 2022, dates the commenter referenced 
are the issuance dates specified in the signature block at the end of 
each AD (i.e., the dates on which the ADs were issued by the FAA). No 
change to this AD is necessary because the citation dates are the 
correct publication dates.

Request To Extend Compliance Time

    Comment summary: Southwest Airlines and American Airlines expressed 
concern regarding the compliance time for the proposed actions and 
requested the FAA revise the AD to provide a minimum of 30 days from 
the effective date of the AD.

[[Page 39997]]

    FAA response: The FAA understands the commenters' concerns and made 
every effort to publish this AD as soon as possible. After refraining 
from operating at their FCC-authorized levels for a year and a half, 
wireless companies are now able to operate at higher levels, yet still 
not at the levels authorized. Specifically, wireless companies expect 
to operate their networks in urban areas with minimal restrictions due 
to the completion of retrofits. Additionally, the FAA anticipates 19 
additional telecommunication companies will begin transmitting in the 
C-Band after June 30, 2023. Although the FAA continues to work with the 
companies that intend to transmit in the 3.7-3.98-GHz band near 5G 
CMAs, the FAA has no agreement with those companies to provide the FAA 
with tower locations and other information necessary to support the 
current NOTAM/AMOC process. Therefore, the FAA will not be able to 
extend the June 30, 2023, date.

Effect of Winglets on Accomplishment of the Proposed Actions

    Comment summary: Aviation Partners Boeing stated that installing 
winglets under supplemental type certificate (STC) STC01219SE and STC 
ST00830SE on applicable Boeing models does not affect accomplishment of 
the actions specified in the proposed AD.
    FAA response: The FAA agrees. The FAA has not changed this AD in 
this regard.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. This AD is adopted as proposed in the 
NPRM.

Interim Action

    The FAA considers this AD to be 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.

Effective Date

    Section 553(d) of the Administrative Procedure Act (APA) (5 U.S.C. 
551 et seq.) requires publication of a rule not less than 30 days 
before its effective date. However, section 553(d) authorizes agencies 
to make rules effective in less than 30 days when the agency finds 
``good cause.'' Radio altimeters cannot be relied upon to perform their 
intended function if they experience interference from wireless 
broadband operations in the 5G C-Band. This interference can cause 
other airplane systems to not properly function, resulting in increased 
flightcrew workload while on approach with the flight director, 
autothrottle, or autopilot engaged. To address this unsafe condition, 
the actions required by this AD must be accomplished before the 
compliance date of June 30, 2023. The FAA based this date 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. The 
earlier operators learn of the requirements in this AD, the earlier 
they can take action to ensure compliance. An effective date less than 
30 days would ensure the AD is codified earlier, thereby increasing 
awareness of its requirements. Therefore, the FAA finds that good cause 
exists pursuant to 5 U.S.C. 553(d) for making this amendment 
immediately effective.

Costs of Compliance

    The cost information below describes the costs to change the AFM. 
Although this AD largely maintains the AFM limitations currently 
required by AD 2022-05-04, the FAA acknowledges that this AD may also 
impose costs on some aircraft operators from having to change their 
conduct to comply with the amended AFM. However, the FAA lacks the data 
necessary to quantify the costs associated with aircraft operators 
changing their conduct.
    The FAA estimates that this AD affects 2,328 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 (retained actions from AD  1 work-hour x $85 per                 $0             $85        $197,880
 2022-05-04).                            hour \1\ = $85.
New AFM revisions (new action)........  1 work-hour x $85 per                  0              85     \2\ 197,880
                                         hour = $85.
----------------------------------------------------------------------------------------------------------------
\1\ The labor rate of $85 per hour is the average wage rate for an aviation mechanic.
\2\ The estimated cost for this revision would 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 737-
  100, -200, -200C, -300, -400, -500, -600, -700, -700C, -800, -900, or -900ER transport category airplane.

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,
    (2) Will not affect intrastate aviation in Alaska, and

[[Page 39998]]

    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The 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 (AD) 2022-05-04, Amendment 39-21955 
(87 FR 10299, February 24, 2022), and
0
b. Adding the following new AD:

2023-12-13 The Boeing Company: Amendment 39-22471; Docket No. FAA-
2023-0921; Project Identifier AD-2022-01430-T.

(a) Effective Date

    This airworthiness directive (AD) is effective June 21, 2023.

(b) Affected ADs

    This AD replaces AD 2022-05-04, Amendment 39-21955 (87 FR 10299, 
February 24, 2022) (AD 2022-05-04).

(c) Applicability

    This AD applies to all The Boeing Company 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) 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] TR21JN23.078

    (ii) Tolerance to radio altimeter interference, for the spurious 
emissions (3.7-3.98 GHz), at or above the PSD curve threshold 
specified in figure 2 to paragraph (g)(2)(ii) of this AD.


[[Page 39999]]


Figure 2 to paragraph (g)(2)(ii)--Spurious Effective Isotropic PSD 
at Outside Interface of Aircraft Antenna
[GRAPHIC] [TIFF OMITTED] TR21JN23.079

    (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) Retained Airplane Flight Manual (AFM) Revision

    This paragraph restates the requirements of paragraph (g) of AD 
2022-05-04.
    (1) Within 2 days after February 24, 2022 (the effective date of 
AD 2022-05-04): Revise the Limitations Section of the existing AFM 
to include the information specified in figure 3 to paragraph (h)(1) 
of this AD. This may be done by inserting a copy of figure 3 to 
paragraph (h)(1) of this AD into the existing AFM.


[[Page 40000]]


Figure 3 to paragraph (h)(1)--AFM Limitations Revisions
[GRAPHIC] [TIFF OMITTED] TR21JN23.080

    (2) Within 2 days after February 24, 2022 (the effective date of 
AD 2022-05-04): Revise the Operating Procedures Section of the 
existing AFM to include the information specified in figure 4 to 
paragraph (h)(2) of this AD or figure 5 to paragraph (h)(2) of this 
AD, as applicable. This may be done by inserting a copy of figure 4 
to paragraph (h)(2) or figure 5 to paragraph (h)(2) of this AD, as 
applicable, into the Operating Procedures Section of the existing 
AFM.

Figure 4 to paragraph (h)(2)--AFM Operating Procedures Revision for 
Model 737-100, -200, -200C, -300, -400, and -500 series airplanes
[GRAPHIC] [TIFF OMITTED] TR21JN23.081


[[Page 40001]]


Figure 5 to paragraph (h)(2)--AFM Operating Procedures Revision for 
Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes
[GRAPHIC] [TIFF OMITTED] TR21JN23.082

(i) New Requirement: AFM Limitations Revision for Non-Radio Altimeter 
Tolerant Airplanes

    For non-radio altimeter tolerant airplanes, do the actions 
specified in paragraphs (i)(1) and (2) of this AD.
    (1) On or before June 30, 2023, revise the Limitations Section 
of the existing AFM to include the information specified in figure 6 
to paragraph (i) of this AD. This may be done by inserting a copy of 
figure 6 to paragraph (i) of this AD into the existing AFM. 
Incorporating the AFM revision required by this paragraph terminates 
the AFM revision required by paragraph (h)(1) of this AD.
    (2) Before further flight after incorporating the limitations 
specified in figure 6 to paragraph (i) of this AD, remove the AFM 
revision required by paragraph (h)(1) of this AD.

Figure 6 to paragraph (i)--AFM Limitations Revision for Non-Radio 
Altimeter Tolerant Airplanes
[GRAPHIC] [TIFF OMITTED] TR21JN23.083

(j) New Requirement: AFM Limitations Revision for Radio Altimeter 
Tolerant Airplanes

    For radio altimeter tolerant airplanes, do the actions specified 
in paragraphs (j)(1) and (2) of this AD.
    (1) On or before June 30, 2023, revise the Limitations Section 
of the existing AFM to include the information specified in figure 7 
to paragraph (j) of this AD. This may be done by inserting a copy of 
figure 7 to paragraph (j) of this AD into the existing AFM. 
Incorporating the AFM revision required by this paragraph terminates 
the AFM revision required by paragraph (h)(1) of this AD.
    (2) Before further flight after incorporating the limitations 
specified in figure 7 to paragraph (j) of this AD, remove the AFM

[[Page 40002]]

revision required by paragraph (h)(1) of this AD.

Figure 7 to paragraph (j)--AFM Limitations Revision for Radio 
Altimeter Tolerant Airplanes
[GRAPHIC] [TIFF OMITTED] TR21JN23.084

(k) New Requirement: AFM Operating Procedures Revision

    For all airplanes, do the actions specified in paragraphs (k)(1) 
and (2) of this AD.
    (1) On or before June 30, 2023, revise the Operating Procedures 
Section of the existing AFM to include the information specified in 
figure 8 to paragraph (k) of this AD or figure 9 to paragraph (k) of 
this AD, as applicable. This may be done by inserting a copy of 
figure 8 to paragraph (k) of this AD or figure 9 to paragraph (k) of 
this AD, as applicable, into the Operating Procedures Section of the 
existing AFM. Incorporating the AFM revision required by this 
paragraph terminates the AFM revision required by paragraph (h)(2) 
of this AD.
    (2) Before further flight after incorporating the operating 
procedures specified in figure 8 to paragraph (k) of this AD or 
figure 9 to paragraph (k) of this AD, remove the AFM revision 
required by paragraph (h)(2) of this AD.

Figure 8 to paragraph (k)--AFM Operating Procedures Revision for 
Model 737-100, -200, -200C, -300, -400, and -500 series airplanes
[GRAPHIC] [TIFF OMITTED] TR21JN23.085


[[Page 40003]]


Figure 9 to paragraph (k)--AFM Operating Procedures Revision for 
Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes
[GRAPHIC] [TIFF OMITTED] TR21JN23.086

(l) Alternative Methods of Compliance (AMOCs)

    (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 (m) 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 requirements 
specified in paragraph (h) of this AD until June 30, 2023.

(m) Related Information

    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].

(n) Material Incorporated by Reference

    None.

    Issued on June 9, 2023.
Michael Linegang,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-13151 Filed 6-16-23; 11:15 am]
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