Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 91, Number 103 (Friday, May 29, 2026)]
[Rules and Regulations]
[Pages 31884-31887]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-10803]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-3422; Project Identifier AD-2025-00763-T; 
Amendment 39-23354; AD 2026-10-14]
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 all 
The Boeing Company Model 747-100, -100B, -100B SUD, -200B, -200C, -
200F, -300, -400, -400D, -400F, 747SP, and 747SR series airplanes. This 
AD was prompted by reports of corrosion damage found on a certain 
satellite communications (SATCOM) high gain antenna adapter plate. This 
AD requires repetitive detailed inspections (DETs) of the SATCOM high 
gain antenna adapter plate for corrosion and applicable on-condition 
actions. The FAA is issuing this AD to address the unsafe condition on 
these products.

DATES: This AD is effective July 6, 2026.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of July 6, 
2026.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2025-3422; 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-2025-3422.

FOR FURTHER INFORMATION CONTACT: Camille Seay, Aviation Safety 
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 817-
222-5149; email: [email protected].

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 The Boeing Company 
Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -
400D, -400F, 747SP, and 747SR series airplanes. The NPRM was published 
in the Federal Register on September 30, 2025 (90 FR 46771). The NPRM 
was prompted by reports of corrosion damage found on a certain SATCOM 
high gain antenna adapter plate. In the NPRM, the FAA proposed to 
require repetitive DETs of the SATCOM high gain antenna adapter plate 
for corrosion and applicable on-condition actions. The FAA is issuing 
this AD to prevent corrosion damage of the SATCOM high gain antenna 
adapter plates. The unsafe condition, if not addressed, could result in 
the SATCOM high gain antenna system parts departing and impacting the 
airplane, which can cause damage that results in loss of continued safe 
flight and landing.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from the Air Line Pilots Association, 
International, (ALPA), Boeing, and a commenter who supported the NPRM 
without change.
    The FAA received additional comments from Cathay Pacific Airways 
Limited (Cathay) and the Citizens Rulemaking Alliance. The following 
presents the comments received on the NPRM and the FAA's response to 
each comment.

Request To Revise the Applicability

    Cathay requested that the FAA revise the applicability of the 
proposed AD to exclude airplanes that have been modified in accordance 
with a certain supplemental type certificate (STC) to remove the 
Inmarsat Antenna and the related adapter plates (part numbers (P/Ns) 
100-602074-000 and 100-602549-000).
    The FAA disagrees. The FAA does not have sufficient information 
regarding that STC to determine if the modification removes all 
components associated with the unsafe condition. Operators may request 
approval of an alternative method of compliance

[[Page 31885]]

(AMOC) under the provisions of paragraph (i) of this AD for airplanes 
that have been modified in accordance with the STC. The FAA has not 
revised this AD in response to this comment.

Request To Justify Forgoing Notice and Comment or Reopen Comment Period

    The Citizens Rulemaking Alliance requested that the FAA either 
provide its justification for finding good cause to bypass notice, if 
invoked, or reopen the comment period for the non-immediate actions. 
The commenter asserted the FAA's use of the good cause exemption 
appears overbroad given the compliance is 1 month instead of before 
further flight.
    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 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 
prepare an initial regulatory flexibility analysis, or 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 including significant alternatives 
considered to minimize the burden on small operators without 
compromising safety.
    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.
    This AD will affect 11 domestic entities, of which eight are small 
entities. The table below displays the industries of the small 
entities, their average annual revenue, and the AD's estimated cost 
burden relative to average annual revenue.

                       Number of Small Entities Affected by Industry and Cost Significance
----------------------------------------------------------------------------------------------------------------
                                                                                                       Cost per
                                 NAICS \1\                                    Number of    Average     AD/annual
 Number of  affected  entities      code            Description \2\           affected      annual      revenue
                                                                              airplanes    revenue        (%)
----------------------------------------------------------------------------------------------------------------
1..............................     532411  Commercial Air, Rail, and Water           1   $1,000,000        0.09
                                             Transportation Equipment
                                             Rental and Leasing.
1..............................     423860  Transportation Equipment and              1    5,590,000        0.02
                                             Supplies Merchant Wholesalers.
1..............................     481219  Other Freight Air                         2      221,410        0.84
                                             Transportation.
1..............................     481112  Scheduled Freight Air                     2   10,330,000        0.02
                                             Transportation.
1..............................     481212  Nonscheduled Chartered Freight            2       58,110        3.22
                                             Air Transportation.
1..............................     481212  Nonscheduled Chartered Freight            4   48,450,000        0.01
                                             Air Transportation.
1..............................     481212  Nonscheduled Chartered Freight            9   55,250,000        0.02
                                             Air Transportation.
1..............................     481212  Nonscheduled Chartered Freight           24  390,000,000        0.01
                                             Air Transportation.
----------------------------------------------------------------------------------------------------------------
\1\ North American Industrial Classification System.
\2\ Dun & Bradstreet. D&B Hoovers. Retrieved April 16, 2026. app.hoovers.dnb.com.

    While the FAA has determined that this AD affects a substantial 
number of small entities, the compliance cost of the AD relative to 
each small entity's annual revenue is minimal. The FAA estimates the 
total cost per affected airplane to be $935 (11 work-hours x $85 per 
work-hour). There is one small business operator whose revenue impact 
exceeds 3% based on the number of affected airplanes in their fleet, 
however, seven small business entities have impacts that are below 1% 
of the average small entity's annual revenue. Therefore, as provided in 
section 605(b), the FAA certifies this AD will not result in a 
significant economic impact on a substantial number of small entities. 
The FAA did not change this AD as a result of this comment.

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

[[Page 31886]]

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.
    The FAA notes that in the preamble of the proposed AD, the FAA 
certified that this regulation is not a ``significant regulatory 
action'' under Executive Order 12866 and will not have an annual effect 
on the economy of $100 million or more. Further, in the Costs of 
Compliance section of the proposed AD, the FAA disclosed the number of 
affected airplanes on the U.S. registry and the number of work hours 
per affected airplane to estimate the cost of the AD on all U.S.-
operators per inspection cycle. The inspection must be repeated every 
48 or 96 months, depending on findings. The FAA did not disclose an 
estimated parts cost since this AD does not require any parts.
    Additionally, the FAA considered the impact that this AD will have 
on affected operators and determined this AD will not trigger any 
downtime costs or scheduling disruptions 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 747-23A2628 RB, 
dated April 18, 2025. This material specifies procedures for repetitive 
DETs of the SATCOM high gain antenna adapter plates for corrosion and 
applicable on-condition actions. On-condition actions include repairing 
the SATCOM high gain antenna adapter plate or replacing it with a new 
or serviceable SATCOM high gain antenna adapter plate if any corrosion 
found is less than or equal to 0.005 inch in depth; and replacing the 
SATCOM high gain antenna adapter plate with a new or serviceable SATCOM 
high gain antenna adapter plate if any corrosion found is greater than 
0.005 inch in depth. 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 115 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
----------------------------------------------------------------------------------------------------------------
Detailed inspection.............  11 work-hours x $85 \1\            $0  $935 per inspection  $107,525 per
                                   per hour = $935 per                    cycle.               inspection cycle.
                                   inspection cycle.
----------------------------------------------------------------------------------------------------------------
\1\ The FAA estimated operators would incur $85 in costs per labor hour, which is the weighted average fiscal
  year (FY) 2026 fully loaded wage of an aircraft mechanic ($69.85) working 60% of the labor hours and a general
  and operations manager ($108.15) working 40% of the labor hours. The FAA estimated these wages by taking
  average the FY 2024 Bureau of Labor Statistics (BLS) air transportation industry average wage for aircraft
  mechanics and general and operations managers (See: Occupational Employment and Wage Statistics Query System,
  BLS (May 2024), data.bls.gov/oes/); multiplying each wage by a fringe benefit factor of 1.42 (See: Employer
  Cost for Employee Compensation--December 2024, BLS (2024), bls.gov/news.release/archives/ecec_03142025.pdf);
  and adjusting these 2024 wages to 2026 dollars using an implicit Gross Domestic Product (GDP) Price Deflator
  of 2.8% (See: Gross Domestic Product: Implicit Price Deflator, FRED (2026) fred.stlouisfed.org/series/GDPDEF).

    The FAA estimates the following costs to do any necessary repairs 
or replacements that would be required based on the results of the 
inspection. The agency has no way of determining the number of aircraft 
that might need these repairs or replacements:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                  Action                               Labor cost               Parts cost     Cost per product
----------------------------------------------------------------------------------------------------------------
Repair adapter plate.....................  5 work-hour x $85 per hour = $425              $0                $425
Replace adapter plate....................  2 work-hour x $85 per hour = $170          18,000              18,170
----------------------------------------------------------------------------------------------------------------

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

[[Page 31887]]

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:

2026-10-14 The Boeing Company: Amendment 39-23354; Docket No. FAA-
2025-3422; Project Identifier AD-2025-00763-T.

(a) Effective Date

    This airworthiness directive (AD) is effective July 6, 2026.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 747-100, -100B, 
-100B SUD, -200B, -200C, -200F, -300, -400, -400D, -400F, 747SP, and 
747SR series airplanes, certificated in any category.

(d) Subject

    Air Transport Association (ATA) of America Code 23, 
Communications system.

(e) Unsafe Condition

    This AD was prompted by reports of corrosion damage found on a 
certain satellite communications (SATCOM) high gain antenna adapter 
plate. The FAA is issuing this AD to prevent corrosion damage of the 
SATCOM high gain antenna adapter plates. The unsafe condition, if 
not addressed, could result in the SATCOM high gain antenna system 
parts departing and impacting the airplane, which can cause damage 
that results 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 747-23A2628 RB, dated April 18, 2025, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
747-23A2628 RB, dated April 18, 2025.

    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
747-23A2628, dated April 18, 2025, which is referred to in Boeing 
Alert Requirements Bulletin 747-23A2628 RB, dated April 18, 2025.

(h) Exception to Requirements Bulletin Specifications

    Where Boeing Alert Requirements Bulletin 747-23A2628 RB, dated 
April 18, 2025, refers to the original issue date of Requirements 
Bulletin 747-23A2628 RB, this AD requires using the effective date 
of this AD.

(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 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: 
[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.

(j) Additional Information

    (1) For more information about this AD, contact Camille Seay, 
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 
98198; phone: 817-222-5149; email: [email protected].
    (2) Material identified in this AD that is not incorporated by 
reference is available at the address specified in paragraph (k)(3) 
this AD.

(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 Alert Requirements Bulletin 747-23A2628 RB, dated 
April 18, 2025.
    (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 [email protected].

    Issued on May 11, 2026.
Lona C. Saccomando,
Acting Deputy Director, Integrated Certificate Management Division, 
Aircraft Certification Service.
[FR Doc. 2026-10803 Filed 5-28-26; 8:45 am]
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