[Federal Register Volume 89, Number 58 (Monday, March 25, 2024)]
[Proposed Rules]
[Pages 20555-20558]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-06130]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0761; Project Identifier AD-2023-01256-T]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain The Boeing Company Model 777 airplanes. This proposed AD 
was prompted by a determination that the nitrogen enriched air 
distribution system (NEADS) cover plate assembly attached to a certain 
vent stringer in the center wing tank was installed without a designed 
electrical bond. This proposed AD would require installing electrical 
bonding and grounding, installing the cover plate assembly with new 
fasteners, and revising the existing maintenance or inspection program, 
as applicable, to incorporate new airworthiness limitations. The FAA is 
proposing this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by May 9, 
2024.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to regulations.gov. Follow 
the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-0761; or in person at

[[Page 20556]]

Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The AD docket contains this NPRM, any comments 
received, and other information. The street address for Docket 
Operations is listed above.
    Material Incorporated by Reference:
     For service information, contact Boeing Commercial 
Airplanes, Attention: Contractual & Data Services (C&DS), 2600 
Westminster Boulevard, MC 110-SK57, Seal Beach, CA 90740-5600; 
telephone 562-797-1717; website myboeingfleet.com.
     You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 2200 South 
216th Street 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 by searching for and locating Docket No. FAA-2024-0761.

FOR FURTHER INFORMATION CONTACT: Anthony Decaro, Aviation Safety 
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; 
telephone: 562-627-5374; email: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2024-0761; Project Identifier 
AD-2023-01256-T'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, 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 proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
regulations.gov, including any personal information you provide. The 
agency will also post a report summarizing each substantive verbal 
contact received about this NPRM.

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 NPRM 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 NPRM, 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 NPRM. Submissions containing CBI should be sent to 
Anthony Decaro, Aviation Safety Engineer, FAA, 2200 South 216th Street, 
Des Moines, WA 98198; telephone: 562-627-5374; 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.

Background

    The FAA has received a report indicating a production audit by the 
design approval holder found that the design of the NEADS cover plate 
assembly did not comply with the requirements for nitrogen generation 
system certification (14 CFR 25.981). It was discovered that the cover 
plate assembly was installed without a designed electrical bond for 
electrostatic dissipation. As a result, Boeing has changed the cover 
plate assembly installation procedure to include a new electrical bond 
between the cover plate assembly and vent stringer No. 15. In addition, 
new stainless steel alloy fasteners are used to attach the cover plate 
assembly to vent stringer No. 15. The accumulation of electrostatic 
charge in the cover plate assembly and the float valve assembly, which 
is attached to the cover plate assembly, could lead to electrostatic 
discharge to the surrounding structure. This condition, if not 
addressed, could result in an ignition source inside the fuel tank and 
subsequent fire or explosion.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 777-47A0007 RB, 
dated November 21, 2023. This service information specifies procedures 
for removing the cover plate assembly and its attached float valve 
assembly, installing electrical bonding and grounding, measuring the 
bonding resistance between the bolt heads/cover plate assembly/float 
valve assembly mounting flange and the vent stringer No. 15 and between 
the nuts and the cover plate assembly, and installing the cover plate 
assembly with new fasteners. The service information also requires 
revising the operator's maintenance or inspection program, as 
applicable, by incorporating new airworthiness limitations (AWLs). This 
service information is reasonably available because the interested 
parties have access to it through their normal course of business or by 
the means identified in ADDRESSES.

Proposed AD Requirements in This NPRM

    This proposed AD would require accomplishing the actions specified 
in the service information already described, except for any 
differences identified as exceptions in the regulatory text of this 
proposed AD. For information on the procedures and compliance times, 
see this service information at regulations.gov under Docket No. FAA-
2024-0761.
    This proposed AD would require revisions to certain operator 
maintenance documents to include new actions (e.g., inspections) and 
Critical Design Configuration Control Limitations (CDCCLs). Compliance 
with these actions and CDCCLs is required by 14 CFR 91.403(c). For 
airplanes that have been previously modified, altered, or repaired in 
the areas addressed by this proposed AD, the operator may not be able 
to accomplish the actions described in the revisions. In this 
situation, to comply with 14 CFR 91.403(c), the operator must request 
approval for an alternative method of compliance according to paragraph 
(j) of this proposed AD.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 292 airplanes of U.S. registry. The FAA estimates the following 
costs to comply with this proposed AD:

[[Page 20557]]



                                                 Estimated Costs
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                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Electrical bond installation..........  27 work-hours x $85 per              $93          $2,388        $697,296
                                         hour = $2,295.
----------------------------------------------------------------------------------------------------------------

    The FAA has determined that revising the existing maintenance or 
inspection program takes an average of 90 work-hours per operator, 
although the agency recognizes that this number may vary from operator 
to operator. Since operators incorporate maintenance or inspection 
program changes for their affected fleet(s), the FAA has determined 
that a per-operator estimate is more accurate than a per-airplane 
estimate. Therefore, the agency estimates the average total cost per 
operator to be $7,650 (90 work-hours x $85 per work-hour).

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

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, and
    (3) Would 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 Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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:

The Boeing Company: Docket No. FAA-2024-0761; Project Identifier AD-
2023-01256-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by May 9, 2024.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 777-200, -200LR, -
300, -300ER, and 777F series airplanes, certificated in any 
category, as identified in Boeing Alert Requirements Bulletin 777-
47A0007 RB, dated November 21, 2023.

(d) Subject

    Air Transport Association (ATA) of America Code 28, Fuel.

(e) Unsafe Condition

    This AD was prompted by a determination that the nitrogen 
enriched air distribution system (NEADS) cover plate assembly 
attached to vent stringer No. 15 in the center wing tank was 
installed without a designed electrical bond. The FAA is issuing 
this AD to address the accumulation of electrostatic charge in the 
cover plate assembly and float valve assembly, which could lead to 
electrostatic discharge to the surrounding structure. The unsafe 
condition, if not addressed, could result in result in an ignition 
source inside the fuel tank and subsequent fire or explosion.

(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 777-47A0007 RB, dated November 21, 2023, 
do all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
777-47A0007 RB, dated November 21, 2023.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
777-47A0007, dated November 21, 2023, which is referred to in Boeing 
Alert Requirements Bulletin 777-47A0007 RB, dated November 21, 2023.

(h) Exceptions to Service Information Specifications

    (1) Where the ``Effectivity'' paragraph and Compliance Time 
columns of the tables in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 777-47A0007 RB, dated November 21, 2023, 
uses the phrase ``the Original Issue date of Requirements Bulletin 
777-47A0007 RB,'' this AD requires using the effective date of this 
AD.
    (2) Where the Compliance Time for ACTION 3: Incorporate 
Maintenance Planning Document (MPD), in the ``Compliance'' paragraph 
of Boeing Alert Requirements Bulletin 777-47A0007 RB, dated November 
21, 2023, is ``Before further flight after accomplishing ACTION 1 
and ACTION 2,'' this AD requires incorporating the MPD within 60 
days after the effective date of this AD.

(i) No Alternative Actions, Intervals, or Critical Design Configuration 
Control Limitations (CDCCLs)

    After the existing maintenance or inspection program has been 
revised as required by paragraph (g) of this AD, no alternative 
actions (e.g., inspections), intervals, or CDCCLs may be used unless 
the actions, intervals, and CDCCLs are approved as an alternative 
method of compliance (AMOC) in accordance with the procedures 
specified in paragraph (j) of this AD.

(j) 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 the certification office,

[[Page 20558]]

send it to the attention of the person identified in paragraph (k) 
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) 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.

(k) Related Information

    (1) For more information about this AD, contact Anthony Decaro, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; telephone: 562-627-5374; email: [email protected].
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the address specified in 
paragraph (l)(3) of this AD.

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Requirements Bulletin 777-47A0007 RB, dated 
November 21, 2023.
    (ii) [Reserved]
    (3) For service information, contact Boeing Commercial 
Airplanes, Attention: Contractual & Data Services (C&DS), 2600 
Westminster Boulevard, 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 
Street, 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/ibr-locations or email [email protected].

    Issued on March 19, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2024-06130 Filed 3-22-24; 8:45 am]
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