[Federal Register Volume 89, Number 191 (Wednesday, October 2, 2024)]
[Rules and Regulations]
[Pages 80077-80080]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-22802]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2317; Project Identifier AD-2024-00468-T; 
Amendment 39-22856; AD 2024-19-14]
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 
certain The Boeing Company Model 777-200, 777-200LR, 777-300ER, and 
777F series airplanes. This AD was prompted by a report of potential 
latent failures of the lightning protection features for the engine 
fuel feed system. This AD requires repetitive inspections and bond 
resistance measurement of the bonding jumpers on the first fuel feed 
tube installed immediately forward of the wing front spar at each of 
the two engine locations, and applicable corrective actions. The FAA is 
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective October 17, 2024.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of October 17, 
2024.
    The FAA must receive comments on this AD by November 18, 2024.

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 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.
    AD Docket: You may examine the AD docket at regulations.gov by 
searching for and locating Docket No. FAA-2024-2317; 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 Docket 
Operations is listed above.
    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-2024-2317.

FOR FURTHER INFORMATION CONTACT: Samuel Dorsey, Aviation Safety 
Engineer, FAA, 2200 South 216th St, Des Moines, WA 98198; phone: 206-
231-3415; email: <a href="/cdn-cgi/l/email-protection#e9ba88849c8c85c7a3c7ad869b9a8c90a98f8888c78e869f"><span class="__cf_email__" data-cfemail="87d4e6eaf2e2eba9cda9c3e8f5f4e2fec7e1e6e6a9e0e8f1">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION: 

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 
the ADDRESSES section. Include Docket No. FAA-2024-2317 and Project 
Identifier AD-2024-00468-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 
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 Samuel 
Dorsey, Aviation Safety Engineer, FAA, 2200 South 216th St, Des Moines, 
WA 98198; phone: 206-231-3415; email: <a href="/cdn-cgi/l/email-protection#fcaf9d91899990d2b6d2b8938e8f9985bc9a9d9dd29b938a"><span class="__cf_email__" data-cfemail="84d7e5e9f1e1e8aaceaac0ebf6f7e1fdc4e2e5e5aae3ebf2">[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.

Background

    In 2023, the FAA received reports of latent failures of the 
lightning protection features for the engine fuel feed system on Boeing 
Model 747 airplanes. Subsequent analysis has shown that

[[Page 80078]]

similar failures are expected to be present on Model 777 airplanes.
    The electrical bonding of the engine fuel feed tube penetrating the 
fuel tanks of Boeing Model 777 airplanes and other Boeing airplane 
models is the primary design feature to prevent the development of an 
ignition source inside the fuel tank during a lightning strike to the 
engine nacelle. The fuel feed lightning protection features include the 
spar bulkhead fitting that redirects the majority of current during a 
lightning event. Separate bonding jumpers outside and inside the fuel 
tank provide additional electrical paths for current from lightning 
strikes. An additional non-bonding feature, an encapsulation seal over 
the spar fitting inside the fuel tank, provides additional protection 
from sparking at that location.
    In related rulemaking, the FAA issued AD 2023-23-14, Amendment 39-
22616 (88 FR 83494, November 30, 2023) (AD 2023-23-14), to address this 
unsafe condition on Model 747 airplanes.
    From analysis of reports submitted in connection with AD 2023-23-
14, Boeing and the FAA have determined that Model 777 airplanes are 
likely to experience similar encapsulation and bonding failures to 
those seen on Model 747 airplanes. On Model 747 airplanes, the bonding 
jumper outside the fuel tank is failing at an excessive rate in 
addition to the known degradation of the primary electrical bonding 
path through the spar fitting. Furthermore, multiple failures of the 
spar fitting's encapsulation have been reported. Model 777 airplanes 
are expected to be affected to a similar or somewhat lesser degree. 
While no reports of failed encapsulations or jumper bonds have been 
received for Model 777 airplanes, these features are generally only 
inspected and/or replaced conditionally, and they share substantial 
similarity to Model 747 airplanes. The fuel feed line encapsulation 
seals are located inside the fuel tank and therefore would generally 
not be inspected closely unless there was a specific maintenance 
concern with the fuel feed fitting. Poor electrical bonding would not 
be expected to be detected during on-condition maintenance as 
electrical bonding is a function of the installation, and the relevant 
component would likely be removed without a resistance measurement. 
Upon replacement, the component installation would be measured and 
adjusted as necessary to meet the relevant bonding requirements in the 
Instructions for Continued Airworthiness.
    The spar fitting's encapsulation is designed to isolate any sparks 
or arcing generated at the bulkhead fitting during a lightning strike 
because of failed electrical bonds from flammable fuel vapors in the 
tank. This fitting, including the in-tank coupler connecting the fuel 
feed line to the fitting, is the most probable location for sparking 
when electrical bonding is poor. Therefore, an unreliable encapsulation 
significantly increases the risk of a fuel tank explosion following a 
lightning strike to the engine nacelle on an airplane with poor 
electrical bonding. Analysis has shown that at least a subset of the 
encapsulation failures seen on Model 747 airplanes is expected on Model 
777 airplanes.
    Model 777 airplanes are equipped with bonding jumpers connecting 
the fuel feed line to the airplane structure at two locations on each 
wing: immediately forward of the front spar, and in the upper portion 
of the engine strut area. These jumpers provide an alternative 
lightning current path to the airplane structure, reducing current 
passed into the fuel tank. However, airplanes produced with General 
Electric Company GE90 series engines were designed without the 
additional bonding jumper installation in the engine strut area that 
would otherwise sufficiently reduce the risk of a lightning strike that 
would result in the unsafe condition. The FAA may issue further 
rulemaking to address all Model 777 airplanes including those powered 
by Pratt & Whitney and Rolls-Royce engines.
    A lightning strike to an engine nacelle combined with a latent 
failure of the lightning protection features for the engine fuel feed 
system, if not addressed, could result in the potential for ignition 
sources inside fuel tanks. This condition, in combination with 
flammable fuel vapors, if not addressed, could result in a fuel tank 
explosion and consequent loss of the airplane. 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.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed Boeing Multi Operator Message MOM-MOM-24-0463-01B, 
dated September 4, 2024. The material specifies procedures for 
inspecting and measuring the bond resistance of the bonding jumpers on 
the first fuel feed tube installed immediately forward of the wing 
front spar at each of the two engine locations, which includes the 
following actions:
    <bullet> repetitive detailed inspections of the two fuel feed tube 
saddle clamps to detect contact between the saddle clamps' metal 
components with the fuel tube;
    <bullet> repetitive detailed inspections of the engine fuel feed 
tube to wing structure bonding jumpers and tube clamps immediately 
forward of the wing front spar for damage to the bonding jumpers or any 
loose bonding jumper lugs or tube clamps; and
    <bullet> repetitive measurement of the electrical bonding 
resistance between the wing structure and engine fuel feed tube.
    The material also specifies procedures for applicable corrective 
actions, which include the following:
    <bullet> reworking of the bonding jumper or saddle clamp 
installation;
    <bullet> replacing saddle clamps whose metal contacts the fuel 
tube;
    <bullet> cleaning and replacing damaged bonding jumpers and related 
hardware; and
    <bullet> contacting Boeing for repair instructions if any 
resistance measurement exceeds specified limits and doing the repair 
instructions.
    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.

AD Requirements

    This AD requires accomplishing the actions specified in the 
material already described, except for any differences identified as 
exceptions in the regulatory text of this AD and except as discussed 
under ``Difference Between this AD and the Referenced Material.''
    For information on the procedures, see this material at 
regulations.gov under Docket No. FAA-2024-2317.

Interim Action

    The FAA considers this AD to be an interim action. The manufacturer 
is currently developing a more comprehensive inspection that will 
address both out-of-tank and in-tank lightning protection features. 
Once this inspection is developed, approved, and available, the FAA 
might consider additional rulemaking.

Justification for Immediate Adoption and Determination of the Effective 
Date

    Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C. 
551 et seq.) authorizes agencies to dispense with notice and comment 
procedures

[[Page 80079]]

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 a lightning strike to an engine nacelle combined with latent 
failures of the lightning protection features for the engine fuel feed 
system could result in the potential for ignition sources inside fuel 
tanks. This condition, in combination with flammable fuel vapors could 
result in a fuel tank explosion and consequent loss of the airplane. 
Accordingly, notice and opportunity for prior public comment are 
impracticable and contrary to the public interest pursuant to 5 U.S.C. 
553(b).
    The compliance time in this AD is shorter than the time necessary 
for the public to comment and for publication of the final rule. 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.

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 174 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
----------------------------------------------------------------------------------------------------------------
Inspection and measurement.......  3 work-hours x $85             $0  $255 per inspection   $44,370 per
                                    per hour = $255 per                cycle.                inspection cycle.
                                    inspection cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any on-condition 
actions that would be required based on the results of the inspection 
and measurement. The FAA has no way of determining the number of 
aircraft that might need these actions:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replacing saddle clamp........................  0.5 work-hour x $85 per hour =                $3          $45.50
                                                 $42.50.
Reworking bonding jumper installation.........  1.0 work-hour x $85 per hour =                 0              85
                                                 $85.
Replacing bonding jumper......................  1.0 work-hour x $85 per hour =                 3              88
                                                 $85.
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition repair specified in this AD.

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:

2024-19-14 The Boeing Company: Amendment 39-22856; Docket No. FAA-
2024-2317; Project Identifier AD-2024-00468-T.

(a) Effective Date

    This airworthiness directive (AD) is effective October 17, 2024.

[[Page 80080]]

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 777-200, 777-200LR, 
777-300ER, and 777F series airplanes, certificated in any category, 
with General Electric Company (GE) GE90-76B, GE90-85B, GE90-90B, 
GE90-94B, GE90-110B1, and GE90-115B model turbofan engines 
installed.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a report of potential latent failures of 
the lightning protection features for the engine fuel feed system. 
The FAA is issuing this AD to address such latent failures. A 
lightning strike to an engine nacelle combined with latent failures 
of the lightning protection features for the engine fuel feed 
system, if not addressed, could result in the potential for ignition 
sources inside fuel tanks, which, in combination with flammable fuel 
vapors, could result in a fuel tank explosion and consequent loss of 
the airplane.

(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: Within 90 days 
after the effective date of this AD, or within 1 year after the date 
of issuance of the original airworthiness certificate or original 
export certificate of airworthiness, whichever comes later, do 
detailed inspections and measure the bond resistance of the bonding 
jumpers on the fuel feed tube installed immediately forward of the 
wing front spar at each of the two engine locations, and do all 
applicable corrective actions, in accordance with the Part 2 of the 
Work Instructions of Boeing Multi Operator Message MOM-MOM-24-0463-
01B, dated September 4, 2024. All applicable corrective actions must 
be done before further flight. Repeat the inspections and bonding 
resistance measurement thereafter at intervals not to exceed 1 year.

(h) Exception to Service Information Specifications

    (1) Where Boeing Multi Operator Message MOM-MOM-24-0463-01B, 
dated September 4, 2024, specifies contacting Boeing for 
instructions if a bonding resistance measurement continues to exceed 
specified limits after multiple failed corrective action attempts, 
this AD requires doing a repair before further flight using a method 
approved in accordance with the procedures specified in paragraph 
(i) of this AD.
    (2) Boeing Multi Operator Message MOM-MOM-24-0463-01B, dated 
September 4, 2024, refers to Aircraft Illustrated Parts Catalogue 
(AIPC) AIPC 28-11-51-01 in several places; however, the correct AIPC 
reference is AIPC 28-11-51-02.

(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 the certification office, 
send it to the attention of the person identified in paragraph (j) 
of this AD. Information may be emailed to <a href="/cdn-cgi/l/email-protection#e5a4a8aaa6a5838484cb828a93"><span class="__cf_email__" data-cfemail="9ddcd0d2deddfbfcfcb3faf2eb">[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

    For more information about this AD, contact Samuel Dorsey, 
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 
98198; phone: 206-231-3415; email: <a href="/cdn-cgi/l/email-protection#4714262a32222b690d6903283534223e0721262669202831"><span class="__cf_email__" data-cfemail="7d2e1c1008181153375339120f0e18043d1b1c1c531a120b">[email protected]</span></a>.

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference 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 Multi Operator Message MOM-MOM-24-0463-01B, dated 
September 4, 2024.
    (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/ibr-locations or email <a href="/cdn-cgi/l/email-protection#0b6d79256265787b6e687f6264654b656a796a256c647d"><span class="__cf_email__" data-cfemail="91f7e3bff8ffe2e1f4f2e5f8feffd1fff0e3f0bff6fee7">[email protected]</span></a>.

    Issued on September 20, 2024.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-22802 Filed 9-30-24; 11:15 am]
BILLING CODE 4910-13-P


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