Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 91, Number 143 (Tuesday, July 28, 2026)]
[Rules and Regulations]
[Pages 47129-47139]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-15239]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-2546; Project Identifier AD-2025-01060-T; 
Amendment 39-23414; AD 2026-15-02]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2024-19-
14, which applied to certain The Boeing Company Model 777-200, 777-
200LR, 777-300ER, and 777F series airplanes. AD 2024-19-14 required 
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 the left and right main fuel tank penetrations 
and applicable corrective actions. This AD was prompted by a 
determination that additional inspections are required to address the 
unsafe condition. This AD requires repetitive detailed inspections 
(DETs), repetitive bond resistance measurement, and applicable on-
condition actions. This AD also expands the applicability and requires 
revising the existing maintenance or inspection program, as applicable, 
to incorporate a certain airworthiness limitation. The FAA is issuing 
this AD to address the unsafe condition on these products.

DATES: This AD is effective September 1, 2026.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of September 1, 
2026.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket

[[Page 47130]]

No. FAA-2025-2546; 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-2025-2546.

FOR FURTHER INFORMATION CONTACT: Samuel Dorsey, Aviation Safety 
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-
231-3415; email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2024-19-14, Amendment 39-22856 (89 FR 
80077, October 2, 2024) (AD 2024-19-14). AD 2024-19-14 applied to 
certain The Boeing Company Model 777-200, 777-200LR, 777-300ER, and 
777F series airplanes, with General Electric Company (GE) GE90-76B, 
GE90-85B, GE90-90B, GE90-94B, GE90-110B1, and GE90-115B model turbofan 
engines installed. The NPRM was published in the Federal Register on 
September 15, 2025 (90 FR 44340). The NPRM was prompted by a 
determination that additional inspections are required to address the 
unsafe condition. In the NPRM, the FAA proposed to require repetitive 
DETs, repetitive bond resistance measurement, and applicable on-
condition actions. The NPRM also proposed to expand the applicability 
and require revising the existing maintenance or inspection program, as 
applicable, to incorporate a certain airworthiness limitation. 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.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from the Air Line Pilots Association, 
International (ALPA), United Airlines, three individuals, and two 
anonymous commenters who supported the NPRM without change.
    The FAA received additional comments from All Nippon Airways, 
American Airlines (American), Boeing, the Citizens Rulemaking Alliance, 
and two individual commenters. The following presents the comments 
received on the NPRM and the FAA's response to each comment.

Request To Revise the Applicability

    Boeing requested that the FAA revise the applicability of the 
proposed AD by adding a reference to Boeing Alert Requirements Bulletin 
777-28A0098 RB, dated August 15, 2025 (Boeing Alert Requirements 
Bulletin 777-28A0098 RB). Boeing stated Boeing Alert Requirements 
Bulletin 777-28A0097 RB, dated August 14, 2025 (Boeing Alert 
Requirements Bulletin 777-28A0097 RB), and Boeing Alert Requirements 
Bulletin 777-28A0098 RB apply to all Boeing Model 777 series airplanes 
and therefore should both be referenced.
    The FAA notes that the serial numbers listed in the effectivity of 
Boeing Alert Requirements Bulletin 777-28A0097 RB and Boeing Alert 
Requirements Bulletin 777-28A0098 RB each identify all Model 777-200, -
200LR, -300, -300ER, and 777F series airplanes. Therefore, it is not 
necessary to reference any service information in the applicability of 
this AD. Accordingly, the FAA has revised paragraph (c) of this AD to 
specify the AD is applicable to all Boeing Company Model 777-200, -
200LR, -300, -300ER, and 777F series airplanes.

Request To Revise Compliance Time for Certain Airplanes

    Boeing requested that the FAA add an exception to paragraph (h) of 
the proposed AD, for airplanes equipped with GE engines, to allow the 
compliance time to be calculated from the most recent inspection 
accomplished using Boeing MOM-MOM-24-0463-01B, dated September 4, 2024 
(Boeing MOM-MOM-24-0463-01B), or Boeing Alert Requirements Bulletin 
777-28A0097 RB. Boeing stated that Boeing Alert Requirements Bulletin 
777-28A0097 RB was approved as equivalent to Boeing MOM-MOM-24-0463-01B 
under an AMOC to AD 2024-19-14. Boeing noted the applicable compliance 
times in tables 1 and 2 of the ``Compliance'' paragraph of Boeing Alert 
Requirements Bulletin 777-28A0097 RB only allow credit for inspections 
accomplished per Boeing MOM-MOM-24-0463-01B.
    The FAA disagrees that an exception to this AD is necessary. 
Paragraph (f) of this AD requires accomplishment of the required 
actions within the specified compliance times, unless previously done. 
Therefore, if an airplane was inspected using Boeing Alert Requirements 
Bulletin 777-28A0097 RB as an AMOC to AD 2024-19-14 before the 
effective date of this AD, that airplane is in compliance with the 
initial inspection required by this AD. Thereafter, the next inspection 
must be accomplished in accordance with the requirements of this AD. 
The FAA has not changed this AD in this regard.

Request To Provide a Grace Period for Certain Airplanes

    An individual commenter requested that the FAA consider revising 
paragraph (h)(1) of the proposed AD to require using the effective date 
of the proposed AD rather than October 17, 2024, the effective date of 
AD 2024-19-14. The commenter stated that using the effective date of AD 
2024-19-14 would not allow a sufficient grace period for operators to 
comply with the proposed AD if the inspections specified in Boeing MOM-
MOM-24-0463-01B have not been previously accomplished on the affected 
airplanes.
    The FAA disagrees with the request. This AD supersedes AD 2024-19-
14, which the FAA issued as an immediately adopted rule due to the 
urgency and risk associated with the unsafe condition. Accordingly, the 
FAA has determined that this AD must retain the compliance times for 
airplanes that were subject to AD 2024-19-14 to ensure an acceptable 
level of safety. The compliance times in tables 1 and 2 of Boeing Alert 
Requirements Bulletin 777-28A0097 RB are based on the required 
intervals for airplanes subject to AD 2024-19-14, specifically those 
equipped with GE90-series engines. Using the effective date of this AD 
instead of the effective date of AD 2024-19-14 would grant airplanes 
that have not yet completed the required inspections an additional 90 
days after the effective date of this AD, which does not ensure an 
acceptable level of safety.

[[Page 47131]]

The FAA has not changed this AD in this regard.

Request for Exception to Service Information

    All Nippon Airways requested that the FAA add an exception that 
specifies if the initial and repetitive inspections have already been 
accomplished on airplanes equipped with GE engines in accordance with 
Boeing MOM-MOM-24-0463-01B, then the inspections specified in Boeing 
Alert Requirements Bulletin 777-28A0097 RB are not required. The 
commenter stated that Boeing Alert Requirements Bulletin 777-28A0097 RB 
is the subject of an AMOC to AD 2024-19-14, and Boeing advised them 
that if the inspections were accomplished according to Boeing MOM-MOM-
24-0463-01B, then Boeing Alert Requirements Bulletin 777-28A0097 RB is 
not required.
    The FAA disagrees with excluding airplanes equipped with GE engines 
from the requirement in paragraph (g) of this AD to accomplish the 
inspections in accordance with Boeing Alert Requirements Bulletin 777-
28A0097 RB. Boeing Alert Requirements Bulletin 777-28A0097 RB contains 
several improvements to inspection processes, part number 
identification, and the handling of discrepant conditions, which 
collectively improve the quality of maintenance performed. For these 
reasons, the FAA has intentionally not allowed Boeing MOM-MOM-24-0463-
01B to be used as a method of compliance after the effective date of 
this AD.
    The FAA provides the following clarification regarding the AMOC to 
AD 2024-19-14. As described previously, operators already receive 
credit for previous inspections done in accordance with Boeing Alert 
Requirements Bulletin 777-28A0097 RB via paragraph (f) of this AD. 
Boeing Alert Requirements Bulletin 777-28A0097 RB also provides credit 
if inspections were originally accomplished in accordance with Boeing 
MOM-MOM-24-0463-01B. Therefore, while operators cannot continue to use 
Boeing MOM-MOM-24-0463-01B for compliance with this AD, there is no 
adverse impact on operators seeking to comply with this AD who 
previously used either document. The FAA has not changed this AD in 
this regard.

Request To Clarify Different Bonding Resistance Limits

    American requested that the FAA include a Note 2 to paragraph 
(g)(1) of the proposed AD or in the preamble to explain the difference 
in bonding resistance limits for the left and right fuel feed tube to 
wing structure bonding jumpers. American noted Boeing Alert 
Requirements Bulletin 777-28A0097 RB lists different resistance limits 
for Action 1 under several conditions without providing an explanation 
for the difference; however, the difference is explained in Boeing 
Alert Service Bulletin 777-28A0097. American asserted since the 
difference in resistance limits is significant and critical for AD 
compliance, an explanation should clearly be noted in the AD because it 
is not explained in Boeing Alert Requirements Bulletin 777-28A0097 RB.
    The FAA disagrees that an exception to this AD is necessary. 
American is correct that the different acceptable bonding resistance 
limits for the fuel feed tube to wing structure bonding jumpers on the 
left and right wings are intentional and result from differences in 
materials and installations, as noted in Boeing Alert Service Bulletin 
777-28A0097. The FAA agrees that this information is useful to 
operators but providing an explanation is not essential for complying 
with the requirements of the AD. Operators are required to accomplish 
the actions in Boeing Alert Requirements Bulletin 777-28A0097 RB, as 
described, including verifying the correct bonding measurements for 
each wing. Further, as stated in paragraph (g)(1) of this AD, operators 
may refer to Boeing Alert Service Bulletin 777-28A0097 for additional 
guidance for accomplishing the actions in Boeing Alert Requirements 
Bulletin 777-28A0097 RB. Therefore, the FAA has not revised this AD in 
this regard.

Request To Revise Reference in Airworthiness Limitation (AWL)

    Boeing requested that the FAA revise figure 1 to paragraph (i) of 
the proposed AD to replace the reference to ``Service Bulletin 777-
28A0098'' with Aircraft Maintenance Manual (AMM) 28-22-15/201 Temporary 
Revision, published between September 16, 2025, and September 17, 2025, 
or AMM 28-22-15/201 published on or after January 5, 2026, for the 
encapsulation procedure within the AWL. Boeing noted that standard 
practice is to reference AMM tasks in the description section of an AWL 
rather than a service bulletin.
    The FAA agrees and has revised figure 1 to paragraph (i) of this AD 
accordingly.

Request To Address Root Cause of Unsafe Condition

    An individual commenter stated that the proposed AD would help 
increase safety through frequent inspections, but only to a certain 
extent. The commenter further stated that the repetitive inspections do 
not address the root cause of the unsafe condition, and instead the 
affected components should be re-engineered. The commenter noted that 
the FAA has issued other ADs to address similar issues on other Boeing 
airplane models.
    The FAA acknowledges the commenter's concern. As stated in the 
proposed AD, the FAA considers this AD to be interim action. The 
actions required by this AD are intended to mitigate the unsafe 
condition until a terminating action is identified. Once the 
manufacturer has developed a modification to address the unsafe 
condition, the FAA will consider further rulemaking.

Request To Justify Forgoing Notice and Comment or Reopen Comment Period

    The Citizens Rulemaking Alliance requested that if the FAA invoked 
good cause to bypass notice and comment procedures, the FAA either 
provide its justification for doing so, convert this action to an NPRM, 
or stay the effective date until 30 days after its publication in the 
Federal Register.
    The FAA notes the comment was submitted in response to an NPRM for 
which the FAA provided a 45-day comment period. This final rule is 
effective 35 days after its publication in the Federal Register. 
Therefore, no change to this AD is necessary.

Request To Make Incorporation by Reference (IBR) Materials Reasonably 
Available

    The Citizens Rulemaking Alliance requested that the FAA add to the 
AD docket all materials incorporated by reference and extend the 
comment period by at least 45 days after adding the material to the 
docket. The commenter stated that the FAA's current practices for IBR 
frequently fail to meet the legal and regulatory standards for 
reasonable availability.
    The FAA disagrees with extending the comment period. In the 
preamble of the NPRM, the FAA notified the public that the IBR material 
would be available for review at regulations.gov under Docket No. FAA-
2025-3422. This material was posted to the AD docket on October 1, 
2025. Therefore, no change to this AD is necessary.

Request To Comply With the Paperwork Reduction Act (PRA)

    The Citizens Rulemaking Alliance requested that the FAA revise the 
AD to comply with the PRA if reporting is required. If reporting is not 
required, the

[[Page 47132]]

commenter requested the FAA clarify that in the AD.
    The FAA notes this AD does not require reporting. If an AD were to 
require reporting, the preamble of the AD would include a paragraph 
titled ``Paperwork Reduction Act'' that would provide the applicable 
OMB control number, required PRA statements, and the estimated time to 
collect the required information (burden). Any costs associated with 
the reporting requirement would be included in the Costs of Compliance 
section in the preamble of the AD. Therefore, the FAA did not change 
this AD as a result of this comment.

Request To Consider Impact on Small Entities

    The Citizens Rulemaking Alliance requested that the FAA either 
provide the factual basis for its Regulatory Flexibility Act (RFA) 
certification that the AD will not have a significant economic impact 
on a substantial number of small entities, or prepare an initial 
regulatory flexibility analysis.
    The FAA provides the following clarification. The RFA of 1980 (5 
U.S.C. 601-612), as amended by the Small Business Regulatory 
Enforcement Fairness Act of 1996 (Pub. L. 104-121) and the Small 
Business Jobs Act of 2010 (Pub. L. 111-240), requires Federal agencies 
to consider the effects of the regulatory action on small business and 
other small entities and to minimize any significant economic impact. 
The term ``small entities'' comprises small businesses and not-for-
profit organizations that are independently owned and operated and are 
not dominant in their fields, and governmental jurisdictions with 
populations of less than 50,000.
    The FAA identified 17 operators and one individual with 290 active 
airplanes affected by this AD. Based on the Small Business 
Administration (SBA) size standards shown in the following table, 10 of 
the operators are small.

          Small Business Size Standards: Air Transportation \1\
------------------------------------------------------------------------
        NAICS \2\ code                Description         Size standard
------------------------------------------------------------------------
423860........................  Transportation          175 employees.
                                 Equipment and
                                 Supplies (Except
                                 Motor Vehicle)
                                 Merchant Wholesalers.
481111........................  Scheduled Passenger     1,500 employees.
                                 Air Transportation.
481112........................  Scheduled Freight Air   1,500 employees.
                                 Transportation.
481211........................  Nonscheduled Chartered  1,500 employees.
                                 Passenger Air
                                 Transportation.
481212........................  Nonscheduled Chartered  1,500 employees.
                                 Freight Air
                                 Transportation.
481219........................  Other Nonscheduled Air  $25.0 million.
                                 Transportation.
488190........................  Other Support           $40.0 million.
                                 Activities for Air
                                 Transportation.
492110........................  Couriers and Express    1,500 employees.
                                 Delivery Services.
532411........................  Commercial Air, Rail,   $45.5 million.
                                 and Water
                                 Transportation
                                 Equipment Rental and
                                 Leasing.
------------------------------------------------------------------------
\1\ Source: SBA (2023).
\2\ North American Industrial Classification System.

    The FAA estimates affected operators will incur a one-time 
maintenance program revision cost of $7,650, an annual inspection cost 
for Boeing Alert Requirements Bulletin 777-28A0097 RB of $255, and an 
inspection cost for Boeing Alert Requirements Bulletin 777-28A0098 RB 
of $376 approximately every 3 years. Depending on the results of these 
inspections, operators could also incur costs of $2,211 for all six 
potential on-condition repairs. Consequently, over a three-year period 
of analysis, an operator could incur a minimum cost of $8,791 
(excluding on-condition repairs) or a maximum cost of $11,002 
(including all on-condition repairs). Evaluated at a 7 percent discount 
rate, the low-case scenario results in a present value of $8,170 and an 
annualized cost of $3,113, while the high-case scenario results in a 
present value of $10,236 and an annualized cost of $3,901. The ``Cost 
Impact on Affected Small Entities'' table displays the NAICS code for 
each small operator, their average annual revenue, and the AD's 
estimated low- and high-case annualized cost burden relative to average 
annual revenue.

                                   Cost Impact on Affected Small Entities \1\
----------------------------------------------------------------------------------------------------------------
                                                     Low-case                        High-case
           NAICS Code             Annual revenue    annualized      Percent of      annualized      Percent of
                                        ($)          cost ($)         revenue        cost ($)         revenue
----------------------------------------------------------------------------------------------------------------
481111..........................      $7,470,000          $3,113             0.0          $3,901             0.1
481112..........................     149,400,000           3,113             0.0           3,901             0.0
481211..........................       3,810,000           3,113             0.1           3,901             0.1
481211..........................       4,800,000           3,113             0.1           3,901             0.1
481212..........................       1,750,000           3,113             0.2           3,901             0.2
488190..........................         320,930           3,113             1.0           3,901             1.2
488190..........................      23,250,000           3,113             0.0           3,901             0.0
532411..........................       6,300,000           3,113             0.0           3,901             0.1
532411..........................       2,110,000           3,113             0.1           3,901             0.2
----------------------------------------------------------------------------------------------------------------
\1\ Source: Dun & Bradstreet. D&B Hoovers. Retrieved April 28, 2024. app.hoovers.dnb.com.

Request To Provide Additional Cost Information

    The Citizens Rulemaking Alliance requested that the FAA provide an 
explicit Unfunded Mandates Reform Act (UMRA) determination and a more 
complete cost analysis. The commenter stated that, in addition to 
estimated costs provided in the proposed AD, the FAA should also 
consider airplane downtime, scheduling disruptions, ferry flight and 
maintenance positioning, cost of special tools, pricing of scarce 
parts, engineering and planning time for unique configurations, and the 
ongoing cost of repetitive inspections.

[[Page 47133]]

    The FAA recognizes that, in doing the actions required by an AD, 
operators might incur indirect costs in addition to the direct costs. 
However, because these costs vary significantly and the FAA lacks 
specific data on them, they are not included in the analysis. In the 
Costs of Compliance section of the proposed AD, the FAA disclosed the 
number of affected airplanes on the U.S. registry, number of estimated 
work hours, and estimated parts cost. The number of estimated work 
hours and the cost of parts or special tools, if necessary, are also 
provided by the manufacturer. Additionally, the FAA considered the 
impact that this AD will have on affected operators and determined this 
AD will not trigger any downtime costs because the requirements of this 
AD can be performed during regularly scheduled maintenance. Since the 
FAA has assessed and disclosed the total known costs of the AD 
requirements in the Costs of Compliance section of the proposed AD, and 
the commenter did not provide additional cost data for the FAA to 
consider in its cost analysis, it is not necessary to provide 
additional information in the AD docket. The FAA did not change 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 777-28A0097 RB, 
dated August 14, 2025. This material specifies procedures for 
repetitive DETs of the bonding jumpers installed between the engine 
fuel feel tube and the wing structure immediately forward of the front 
spar at the left and right main fuel tank penetrations, saddle clamps, 
and tube clamps for any damage; repetitive DETs for any loose bonding 
jumper lugs or tube clamps (rotation when rotating with light finger 
pressure); repetitive DETs for any missing bonding jumpers or tube 
clamps; and repetitive measurements of the electrical bonding 
resistance between the wing structure and engine fuel feed tube; and 
applicable on-condition actions. Damage includes bonding jumpers that 
have one or more broken strands in wire braid, saddle clamps with 
split, cracked, broken rubber parts or any contact between saddle 
clamps' metal with the fuel tube, and tube clamps being cracked, broken 
or having a screw hole elongated. On-condition actions include 
removing, cleaning, and re-installing bonding jumpers and related 
hardware, and replacing damaged and missing saddle clamps, bonding 
jumpers and tube clamps.
    The FAA also reviewed Boeing Alert Requirements Bulletin 777-
28A0098 RB, dated August 15, 2025. This material specifies procedures 
for, depending on configuration, repetitive measurement of electrical 
bonding resistance between the front spar and the threaded portion of 
the front spar bulkhead fitting outside the fuel tank at the left and 
right main fuel tank penetrations; repetitive DETs of the bonding 
jumper and tube clamps installed between the engine fuel feed tube and 
the engine nacelle strut for each of the left and right engines for 
correct installation; repetitive measurement of electrical bonding 
resistance between the nacelle strut structure and out-tank engine fuel 
feed tube; and applicable on-condition actions. On-condition actions 
include:
    <bullet> A DET of the front spar bulkhead fitting and coupling 
inside the fuel tank for any area without sealant, any damaged (crack 
or void in sealant, disbonded sealant, or any exposed underlying 
metallic surface) sealant, and any insufficient sealant.
    <bullet> Removing existing sealant and re-applying sealant inside 
the fuel tank.
    <bullet> For Group 1 airplanes, a DET of the bonding jumper and 
tube clamps installed between the first engine fuel feed tube and the 
structure inside the fuel tank for correct installation, and an 
electrical bonding resistance measurement between the first engine fuel 
feed tube and the structure inside the fuel tank.
    <bullet> For Group 2 airplanes, a DET of the bonding jumper and 
tube clamps that are installed between the first engine fuel feed tube 
connected to the front spar bulkhead fitting inside the fuel tank and 
the second AFT in-tank engine fuel feed tube for correct installation, 
and an electrical bonding resistance measurement between the first 
engine fuel feed tube connected to the front spar bulkhead fitting 
inside the fuel tank and the second AFT in-tank engine fuel feed tube.
    <bullet> For Group 2 airplanes, a DET of the bonding jumper and 
tube clamps installed between the second AFT in-tank engine fuel feed 
tube and the structure inside the fuel tank for correct installation, 
and an electrical bonding resistance measurement between the second AFT 
in-tank engine fuel feed tube and the structure inside the fuel tank.
    <bullet> Removing out-tank (engine nacelle strut) and/or in-tank 
bonding jumpers and tube clamps, cleaning electrical bond surfaces, and 
installing new or serviceable bonding jumpers and tube clamps.
    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.

Interim Action

    The FAA considers this AD to be an interim action. The manufacturer 
is currently developing a modification that will address the unsafe 
condition identified in this AD. Once this modification is developed, 
FAA-approved, and available, the FAA might consider additional 
rulemaking.

Costs of Compliance

    The FAA estimates that this AD affects 316 airplanes of U.S. 
registry, of which 290 active airplanes are registered to 18 U.S. 
operators. The FAA estimates the following costs to comply with this 
AD:

                                      Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                     Labor cost          Parts cost     Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Inspections and measurements     3 work-hours x $85 per               $0  $255 per            $80,580 per
 (777-28A0097 RB).                hour = $255 per                          inspection cycle.   inspection cycle.
                                  inspection cycle.
Inspections and measurements     4 work-hours x 85 per                36  $376 per            $118,816 per
 (777-28A0098 RB).                hour = $340 per                          inspection cycle.   inspection cycle.
                                  inspection cycle.
----------------------------------------------------------------------------------------------------------------


[[Page 47134]]

    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 FAA estimates the average total cost per 
operator to be $7,650 (90 work-hours x $85 per work-hour).
    Depending on the results of the required inspections, operators 
could incur costs for on-condition actions. The table below displays 
the estimated costs to do any necessary on-condition action. Since 
these actions are based on the state of the aircraft, the FAA cannot 
determine the number of aircraft that might require these actions.

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                   Action                                 Labor cost                Parts cost        product
----------------------------------------------------------------------------------------------------------------
Bonding jumper cleaning and installation;     2 work-hours x $85 per hour = $170             $26            $196
 saddle clamp, bonding jumper, tube clamp
 replacement (777-28A0097 RB).
DET for encapsulation sealant application     18 work-hours x 85 per hour =                    0           1,530
 (777-28A0098 RB).                             1,530.
Encapsulation sealant reapplication (777-     1 work hour x 85 per hour = 85....              75             160
 28A0098 RB).
In-tank engine fuel feed tube bonding jumper  1 work-hour x 85 per hour = 85....               0              85
 DET and bonding resistance measurement (777-
 28A0098 RB).
In-tank engine fuel feed tube bonding jumper  1 work-hour x 85 per hour = 85....              23             108
 rework and bonding resistance measurement
 (777-28A0098 RB).
Nacelle strut engine fuel feed tube bonding   1 work-hour x 85 per hour = 85....              47             132
 jumper rework and bonding resistance
 measurement (777-28A0098 RB).
----------------------------------------------------------------------------------------------------------------

    To account for the uncertainty regarding on-condition repairs, the 
FAA has established a low-case and high-case cost scenario. The 
analysis covers a three-year period to account for at least one 
inspection per Boeing Alert Requirements Bulletin 777-28A0098 RB, which 
takes place approximately every 3 years.
    In both scenarios, all 18 affected operators incur a one-time 
maintenance program revision cost of $7,650, an annual inspection cost 
of $255 for Boeing Alert Requirements Bulletin 777-28A0097 RB, and $376 
every 3 years for inspection per Boeing Alert Requirements Bulletin 
777-28A0098 RB. The high-case scenario builds upon these costs by 
assuming that every operator will also require on-condition repairs 
associated with inspection per Boeing Alert Requirements Bulletin 777-
28A0098 RB in year 1, adding action cost of $2,211 per operator.
    The tables below display the low- and high-case total compliance 
costs for all 18 operators affected by this AD.

                   Estimated Low-Case Compliance Costs
------------------------------------------------------------------------
             Year                Number of inspections  Total costs \ 1\
------------------------------------------------------------------------
1.............................  18 (777-28A0097 RB) +   $149,058
                                 18 (777-28A0098 RB).
2.............................  18 (777-28A0097 RB)...  4,590
3.............................  18 (777-28A0097 RB)...  4,590
                                                       -----------------
    Total.....................  ......................  158,238
------------------------------------------------------------------------
\1\ Yr 1 = 18 operators x ($7,650 maintenance program revision + $255
  inspection (777-28A0097 RB) + $376 inspection (777-28A0098 RB)).
Yr 2 = 18 operators x $255 inspection cost.
Yr 3 = 18 operators x $255 inspection costs.


                                      Estimated High-Case Compliance Costs
----------------------------------------------------------------------------------------------------------------
                                                                                   On-condition     Total costs
                    Year                            Number of inspections          repairs \ 1\         \2\
----------------------------------------------------------------------------------------------------------------
1..........................................  18 (777-28A0097 RB) + 18 (777-                   18        $188,856
                                              28A0098 RB).
2..........................................  18 (777-28A0097 RB)................               0           4,590
3..........................................  18 (777-28A0097 RB)................               0           4,590
                                                                                                 ---------------
    Total..................................  ...................................  ..............         198,036
----------------------------------------------------------------------------------------------------------------
\1\ All 6 on-condition repairs are counted as one repair in this column.
\2\ Yr 1 = 18 operators x ($7,650 maintenance program revision + $255 inspection (777-28A0097 RB) + $376
  inspection (777-28A0098 RB) + $2,211 on-condition repairs).
Yr 2 = 18 operators x $255 inspection costs.
Yr 3 = 18 operators x $255 inspection costs.

    Per OMB Circular A-4, the table below displays the cumulative 
compliance costs discounted at both 3 percent and 7 percent rates 
alongside annualized costs.

[[Page 47135]]



                                           Summary of Compliance Costs
----------------------------------------------------------------------------------------------------------------
                                   Undiscounted         7%              3%              7%              3%
----------------------------------------------------------------------------------------------------------------
                                                        Present value (PV)
                                            Annualized
----------------------------------------------------------------------------------------------------------------
Low-Case........................        $158,238        $147,062        $142,457         $56,038         $50,363
High-Case.......................         198,036         184,257         178,568          70,211          63,129
----------------------------------------------------------------------------------------------------------------

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:
0
a. Removing Airworthiness Directive (AD) 2024-19-14, Amendment 39-22856 
(89 FR 80077, October 2, 2024); and
0
b. Adding the following new AD:

2026-15-02 The Boeing Company: Amendment 39-23414; Docket No. FAA-
2025-2546; Project Identifier AD-2025-01060-T.
0
(a) Effective Date
    This airworthiness directive (AD) is effective September 1, 2026.
0
(b) Affected ADs
    This AD replaces AD 2024-19-14, Amendment 39-22856 (89 FR 80077, 
October 2, 2024) (AD 2024-19-14).
0
(c) Applicability
    This AD applies to all The Boeing Company Model 777-200, -200LR, -
300, -300ER, and 777F series airplanes, certificated in any category.
0
(d) Subject
    Air Transport Association (ATA) of America Code 28, Fuel.
0
(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.
0
(f) Compliance
    Comply with this AD within the compliance times specified, unless 
already done.
0
(g) Required Actions
    (1) Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 777-28A0097 RB, dated August 14, 2025, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 777-
28A0097 RB, dated August 14, 2025.
    Note 1 to paragraph (g)(1): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 777-
28A0097, dated August 14, 2025, which is referred to in Boeing Alert 
Requirements Bulletin 777-28A0097 RB, dated August 14, 2025.
    (2) Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 777-28A0098 RB, dated August 15, 2025, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 777-
28A0098 RB, dated August 15, 2025.
    Note 2 to paragraph (g)(2): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 777-
28A0098, dated August 15, 2025, which is referred to in Boeing Alert 
Requirements Bulletin 777-28A0098 RB, dated August 15, 2025.

(h) Exceptions to Requirements Bulletin Specifications

    (1) Where the Compliance Time columns of Tables 1 and 2 in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 777-
28A0097, dated August 14, 2025, refer to the original issue date of 
Requirements Bulletin 777-28A0097, this AD requires using October 17, 
2024 (the effective date of AD 2024-19-14).
    (2) Where the Compliance Time columns of Tables 3 and 4 in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 777-
28A0097, dated August 14, 2025, refer to the original issue date of 
Requirements Bulletin 777-28A0097, this AD requires using the effective 
date of this AD.
    (3) Where the Compliance Time columns of the tables in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 777-
28A0098, dated August 15, 2025, refer to the original issue date of 
Requirements Bulletin 777-28A0098, dated August 15, 2025, this AD 
requires using the effective date of this AD.

[[Page 47136]]

(i) Critical Design Configuration Control Limitations (CDCCLs)

    Within 60 days after the effective date of this AD, revise the 
existing maintenance or inspection program, as applicable, to 
incorporate the information specified in Figure 1 and Figure 2 to 
paragraph (i) of this AD.
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(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, send it to the attention of 
the person identified in paragraph (k)(1) of this AD. Information may 
be emailed to: [email protected]. Before using any approved AMOC, notify 
your appropriate principal inspector, or lacking a principal inspector, 
the manager of the responsible Flight Standards Office.
    (2) 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.
    (3) AMOCs approved for AD 2024-19-14 are not approved as AMOCs for 
the corresponding provisions of Boeing Alert Requirements Bulletin 777-
28A0097, dated August 14, 2025, that are required by paragraph (g) of 
this AD.

(k) Additional Information

    (1) 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: [email protected].
    (2) Material 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 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 777-28A0097, dated August 
14, 2025.
    (ii) Boeing Alert Requirements Bulletin 777-28A0098, dated August 
15, 2025.
    (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 [email protected].

    Issued on July 15, 2026.
Lona C. Saccomando,
Acting Deputy Director, Integrated Certificate Management Division, 
Aircraft Certification Service.
[FR Doc. 2026-15239 Filed 7-27-26; 8:45 am]
BILLING CODE 4910-13-P

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