[Federal Register Volume 89, Number 204 (Tuesday, October 22, 2024)]
[Rules and Regulations]
[Pages 84264-84267]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-24369]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0229; Project Identifier AD-2023-00485-T; 
Amendment 39-22848; AD 2024-19-06]
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 adopting a new airworthiness directive (AD) for 
certain The Boeing Company Model 737-8 and Model 737-9 airplanes. This 
AD was prompted by a Boeing review of the standby power system control 
unit (SPCU) design where a single point of failure exists internal to 
the SPCU. This AD requires installing four diodes and changing wire 
bundles in the P5 panel, as well as performing installation and power 
tests and applicable on-condition actions. The FAA is issuing this AD 
to address the unsafe condition on these products.

DATES: This AD is effective November 26, 2024 .
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of November 26, 
2024.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-0229; 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.
    Material Incorporated by Reference:
    <bullet> For Boeing material identified in this AD, 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; website myboeingfleet.com.
    <bullet> You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th St., Des 
Moines, WA. For information on the availability of this material at the 
FAA, call 206-231-3195. It is also available at regulations.gov under 
Docket No. FAA-2024-0229.

FOR FURTHER INFORMATION CONTACT: Raja Vengadasalam, Aviation Safety 
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone 
206-231-3537; email <a href="/cdn-cgi/l/email-protection#3d6f5c575c136b58535a5c595c4e5c515c507d5b5c5c135a524b"><span class="__cf_email__" data-cfemail="73211219125d25161d1412171200121f121e331512125d141c05">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION: 

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain The Boeing 
Company Model 737-8 and Model 737-9 airplanes. The NPRM published in 
the Federal Register on February 14, 2024 (89 FR 11231). The NPRM was 
prompted by a Boeing review of the SPCU design where a single point of 
failure exists internal to the SPCU. In the NPRM, the FAA proposed to 
require installing four diodes and changing wire bundles in the P5 
panel, as well as

[[Page 84265]]

performing installation and power tests and applicable on-condition 
actions. The FAA is issuing this AD to address a potential single point 
of failure in the SPCU, which can result in a non-latent loss of the 
entire battery bus and consequent un-annunciated loss of control and 
indication of both engine anti-ice (EAI) systems.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from eight commenters who supported the 
NPRM without change.
    The FAA received additional comments from Alaska Airlines and two 
individuals. The following presents the comments received on the NPRM 
and the FAA's response to each comment.

Request for a ``Credit for Previous Actions'' Paragraph

    Alaska Airlines requested that the proposed AD be revised to 
include a ``Credit for Previous Actions'' paragraph that gives credit 
as specified in paragraph (h)(2), ``Exceptions to Service Information 
Specifications,'' of the proposed AD. Alaska requested credit for 
``ACTION 3'' in the Action column of the table in the ``Compliance'' 
paragraph of Boeing Alert Requirements Bulletin 737-30A1083 RB, dated 
November 18, 2022, for airplanes on which the requirements bulletin was 
embodied prior to the effective date of this AD.
    The FAA disagrees with revising this AD to include a ``Credit for 
Previous Actions'' paragraph in this AD. Paragraph (f), ``Compliance,'' 
of this AD provides credit for required actions performed before the 
effective date of this AD. The FAA has not changed this AD as a result 
of this comment.

Request for Clarification of AD Actions

    An individual was supportive, but requested clarification of 
whether the proposed AD adequately addresses the unsafe condition to 
prevent the single point of failure addressed by the proposed AD. The 
commenter also questioned what is being done so this condition does not 
occur again, and whether this is the only issue with this airplane 
design. The commenter also requested clarification of whether the 
affected airplanes would be grounded until the proposed AD actions are 
completed.
    The FAA worked with Boeing to develop appropriate actions, i.e., 
the diode installation and wire bundle change, using the procedures 
specified in Boeing Alert Requirements Bulletin 737-30A083 RB, dated 
November 18, 2022, to address the identified unsafe condition in this 
AD. This particular issue is the only one addressed by this AD. The FAA 
continuously evaluates operator and manufacturer reports and other data 
in order to promote safe type certification and production. Operators 
are required to comply with all applicable actions of an AD within the 
required compliance time and cannot later undo those required actions. 
The FAA's safety analysis has determined that the compliance time for 
corrective action in this AD provides an acceptable level of safety. 
The FAA has not changed this AD as a result of this comment.

Request for FAA's Approach to Continued Operational Safety

    Another individual stated that the AD ``prompted a review of'' the 
SPCU and ``found a design flaw.'' The commenter acknowledged that the 
proposed AD would address the underlying problem, but questioned how 
long the condition has existed, whether the SPCU review addresses all 
systems on these airplanes, and whether affected airplanes remain in 
service until the concerns are addressed. This commenter stated that a 
deeper review into other models and ways to address these issues must 
be investigated.
    The FAA provides the following clarification. This AD did not 
prompt the SPCU review; rather, after the SPCU review conducted by 
Boeing, the FAA determined that an AD was necessary and appropriate to 
address the unsafe condition. The FAA continuously receives and 
evaluates performance and safety data from operators and manufacturers 
on all type-certificated airplanes. The FAA takes corrective action--
whether advisory such as an advisory circular or mandatory such as an 
AD--as warranted by the facts. The FAA has not changed this AD as a 
result of this comment.

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. Except for minor editorial changes, this 
AD is adopted as proposed in the NPRM. None of the changes will 
increase the economic burden on any operator.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 737-30A083 RB, 
dated November 18, 2022. This material specifies procedures for 
installing four diodes and changing wire bundles in the P5 panel, as 
well as performing an anti-ice diode installation test and an engine 
anti-ice and wing anti-ice power test and applicable on-condition 
actions. On-condition actions include doing applicable corrective 
actions until the tests are passed.
    This material is reasonably available because the interested 
parties have access to it through their normal course of business or by 
the means identified in the ADDRESSES section.

Costs of Compliance

    The FAA estimates that this AD affects 205 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                   Labor cost          Parts cost       Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Installation, Wiring bundle       Up to 18 work-      Up to $3,760......  Up to $5,290......  Up to $1,084,450.
 changes, and tests.               hours x $85 per
                                   hour = Up to
                                   $1,530.
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition actions specified in this AD.
    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some or all of the costs of 
this AD may be covered under warranty, thereby reducing the cost impact 
on affected operators.

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

[[Page 84266]]

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
    (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 adding the following new airworthiness 
directive:

2024-19-06 The Boeing Company: Amendment 39-22848; Docket No. FAA-
2024-0229; Project Identifier AD-2023-00485-T.

 (a) Effective Date

    This airworthiness directive (AD) is effective November 26, 
2024.

 (b) Affected ADs

    None.

 (c) Applicability

    This AD applies to The Boeing Company Model 737-8 and 737-9 
airplanes, certificated in any category, having a line number 
identified in paragraph 1.A., ``Effectivity,'' of Boeing Alert 
Requirements Bulletin 737-30A1083 RB, dated November 18, 2022.

(d) Subject

    Air Transport Association (ATA) of America Code 30, Ice/Rain 
Protection System.

(e) Unsafe Condition

    This AD was prompted by a Boeing review of the standby power 
system control unit (SPCU) design that determined a potential single 
point of failure exists in the SPCU. The FAA is issuing this AD to 
address a potential single point of failure in the SPCU, which can 
result in a non-latent loss of the entire battery bus and consequent 
un-annunciated loss of control and indication of both engine anti-
ice (EAI) systems. The unsafe condition, if not addressed, could 
result in loss of thrust on both engines due to damage from 
operation in icing conditions without EAI and can result in loss of 
continued safe flight and landing.

(f) Compliance

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

(g) Required Actions

    Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 737-30A1083 RB, dated November 18, 2022, 
do all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-30A1083 RB, dated November 18, 2022.

    Note 1 to paragraph (g):  Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-30A1083, dated November 18, 2022, which is referred to in Boeing 
Alert Requirements Bulletin 737-30A1083 RB, dated November 18, 2022.

(h) Exceptions to Service Information Specifications

    (1) Where the Compliance Time columns of the table in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 737-
30A1083 RB, dated November 18, 2022, uses the phrase ``the original 
issue date of Requirements Bulletin 737-30A1083 RB,'' this AD 
requires using the effective date of this AD.
    (2) Where ``ACTION 3'' in the Action column of the table in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 737-
30A1083 RB, dated November 18, 2022, specifies to do applicable 
corrective actions and repeat the test until the test passes if any 
test fails, for this AD, the compliance time for those actions is 
before further flight after accomplishing the test.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, AIR-520, Continued 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 AIR-520, Continued 
Operational Safety Branch, send it to the attention of the person 
identified in paragraph (j)(1) of this AD. Information may be 
emailed to: <a href="/cdn-cgi/l/email-protection#cb8a8684888badaaaae5aca4bd"><span class="__cf_email__" data-cfemail="1554585a56557374743b727a63">[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) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by The Boeing Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, AIR-
520, Continued Operational Safety Branch, FAA, to make those 
findings. To be approved, the repair method, modification deviation, 
or alteration deviation must meet the certification basis of the 
airplane, and the approval must specifically refer to this AD.

(j) Related Information

    (1) For more information about this AD, contact Raja 
Vengadasalam, Aviation Safety Engineer, FAA, 2200 South 216th St., 
Des Moines, WA 98198; telephone 206-231-3537; email 
<a href="/cdn-cgi/l/email-protection#a0f2c1cac18ef6c5cec7c1c4c1d3c1ccc1cde0c6c1c18ec7cfd6"><span class="__cf_email__" data-cfemail="b6e4d7dcd798e0d3d8d1d7d2d7c5d7dad7dbf6d0d7d798d1d9c0">[email protected]</span></a>.
    (2) Material identified in this AD that is not incorporated by 
reference is available at the addresses specified in paragraph 
(k)(3) of this AD.

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the material listed in this 
paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this material as applicable to do the actions 
required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Requirements Bulletin 737-30A1083 RB, dated 
November 18, 2022.
    (ii) [Reserved]
    (3) For Boeing material identified in this AD, 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; website myboeingfleet.com.
    (4) You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th St., 
Des Moines, WA. For information on the availability of this material 
at the FAA, call 206-231-3195.
    (5) You may view this material at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at NARA, visit www.archives.gov/federal-register/
cfr/

[[Page 84267]]

ibr-locations.html or email <a href="/cdn-cgi/l/email-protection#e08692ce898e9390858394898f8ea08e819281ce878f96"><span class="__cf_email__" data-cfemail="5b3d29753235282b3e382f3234351b353a293a753c342d">[email protected]</span></a>.

    Issued on September 13, 2024.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-24369 Filed 10-21-24; 8:45 am]
BILLING CODE 4910-13-P


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