[Federal Register Volume 91, Number 48 (Thursday, March 12, 2026)]
[Rules and Regulations]
[Pages 12068-12071]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-04832]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-0924; Project Identifier AD-2025-00294-T;
Amendment 39-23274; AD 2026-05-01]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain The Boeing Company Model 787-8, 787-9, and 787-10 airplanes.
This AD was prompted by a report of multiple instances of loss of
transponder for airplanes entering airspace in the presence of
continuous wave (CW) interference where the transponder did not meet
the minimum operational performance standards (MOPS) requirement for
transponder response. This AD requires replacing the left and right
integrated surveillance system processor unit (ISSPU) hardware. The FAA
is issuing this AD to address the unsafe condition on these products.
DATES: This AD is effective April 16, 2026.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of April 16,
2026.
ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2025-0924; 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:
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.
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-2025-0924.
FOR FURTHER INFORMATION CONTACT: Michael Closson, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-
231-3973; 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 certain The Boeing
Company Model 787-8, 787-9, and 787-10 airplanes. The NPRM was
published in the Federal Register on June 13, 2025 (90 FR 25000). The
NPRM was prompted by a report of multiple instances of loss of
transponder for airplanes entering airspace in the presence of CW
interference. The transponder did not meet the MOPS requirement of
transponder response in the presence of CW interference in that the
transponder did not correctly reply to at least 90 percent of the
interrogations. In the NPRM, the FAA proposed to require replacing the
left and right ISSPU hardware. The FAA is issuing this AD to address
loss of transponder when in the presence of CW interference.
Discussion of Final Airworthiness Directive
Comments
The FAA received comments from the Air Line Pilots Association,
International (ALPA), Boeing, and an individual; they supported the
NPRM without requesting a change to the rule.
The FAA received additional comments from ALPA, American Airlines
(American), Kenya Airways, KLM Royal Dutch Airlines (KLM), United
Airlines (United), and an anonymous commenter. The following presents
the comments received on the NPRM and the FAA's response to each
comment.
[[Page 12069]]
Request To Delay of Issuance of the AD
Kenya Airways requested that the FAA postpone issuance of the final
rule mandating installation of ISSPU hardware part number (P/N) 822-
2120-113 until the underlying issues have been fully understood and
appropriately addressed. The commenter stated Boeing, in collaboration
with Collins Aerospace, is actively investigating this issue, but the
root cause has not yet been identified, and the resolution is pending.
The FAA disagrees with delaying issuance of this AD because the FAA
has determined that the affected parts must be replaced to address the
unsafe condition. The FAA will continue to monitor the situation, and
if additional data is presented, the FAA may consider further
rulemaking. The FAA has not changed this AD in regard to this comment.
Request To Consider Parts Availability
KLM and United expressed concerns regarding the availability of
ISSPU P/N 822-2120-113. KLM stated it requested the parts from Collins
Aerospace, but they currently only offer parts in the event an airplane
is subject to an unscheduled removal from service; however, parts would
be available for modification at their facility starting August 2025.
Likewise, United Airlines stated the parts were unavailable when Issue
001 of the Boeing Requirements Bulletin was published on February 11,
2025. United asked if the FAA and Boeing have coordinated with Collins
Aerospace to assess their supply chain capacity, ensuring a feasible
compliance timeline for all operators.
The FAA has coordinated with Collins Aerospace and Boeing, and
Collins Aerospace confirmed it will increase parts availability to
allow operators to meet the compliance time of this AD. Additionally,
under the provisions of paragraph (i) of this AD, the FAA will consider
requests for approval of an extension of the compliance time if
sufficient data is submitted to substantiate that the new compliance
time would provide an acceptable level of safety. The FAA has not
changed this AD in regard to this comment.
Request To Shorten Compliance Time
An anonymous commenter requested that the FAA reduce the proposed
compliance time from 48 months to 12 months because CW interference is
expected to increase annually with the expansion of 5G networks.
The FAA disagrees with the request. The issues surrounding the 5G
network and radio altimeters are not related to the unsafe condition of
this AD. The ISSPU hardware operates on a different bandwidth than the
5G network. The FAA has not changed this AD in regard to this comment.
Request To Clarify Software Requirements
American stated Boeing Alert Service Bulletin B787-81205-SB340065-
00, Issue 001, dated February 11, 2025, includes a procedure to update
software P/N COL49-0010-0091 that is not a required for compliance (RC)
step. American requested the FAA clarify that the intent of the
proposed AD is to replace the ISSPU hardware and not to update the
software, and that therefore operators may install later approved
versions of the software without obtaining an alternative method of
compliance (AMOC).
The FAA confirms that later approved versions of the software may
be installed without obtaining an AMOC because the software
installation is not included as an RC step in Boeing Alert Requirements
Bulletin B787-81205-SB340065-00 RB, Issue 001, dated February 11, 2025.
No change to this AD is necessary in regard to this comment.
Request for Additional Guidance
ALPA requested that the FAA consider providing additional guidance
or alerts to flightcrews regarding transponder failure modes related to
CW interference. ALPA stated that the FAA should continually provide
flightcrews with updated information on the scope of this issue and
procedures where applicable. ALPA also encouraged the FAA to closely
coordinate with Boeing and operators to ensure that replacement
components meet the latest MOPS and are vetted by the appropriate
authorities.
The FAA does not agree with providing additional guidance or
alerts, at this time, regarding the unsafe condition of this AD. Boeing
has already addressed the details of the unsafe condition with
operators and flightcrews through its usual communication methods. The
FAA will continue to work with Boeing to monitor the situation and
provide additional information or guidance as needed. The FAA has
ensured that the new ISSPU hardware (i.e., replacement components)
required by this AD meets the latest MOPS. The FAA has not changed this
AD in regard to 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 B787-81205-
SB340065-00 RB, Issue 001, dated February 11, 2025. This material
specifies procedures for replacing the left and right ISSPU hardware P/
Ns 822-2120-101 and 822-2120-102 with P/N 822-2120-113, performing an
installation test, and repeating the test until it is successful.
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 150 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Replace left and right ISSPU and 4 work-hours x $85 per hour $52,661 $53,001 $7,950,150
ensure a successful installation = $340.
test.
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[[Page 12070]]
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,
(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:
2026-05-01 The Boeing Company: Amendment 39-23274; Docket No. FAA-
2025-0924; Project Identifier AD-2025-00294-T.
(a) Effective Date
This airworthiness directive (AD) is effective April 16, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to The Boeing Company Model 787-8, 787-9, and
787-10 airplanes, certificated in any category, as identified in
Boeing Alert Requirements Bulletin B787-81205-SB340065-00 RB, Issue
001, dated February 11, 2025.
(d) Subject
Air Transport Association (ATA) of America Code 34, Navigation.
(e) Unsafe Condition
This AD was prompted by multiple instances of loss of
transponder for airplanes entering airspace in the presence of
continuous wave (CW) interference where the transponder did not meet
the minimum operational performance standards requirement for
transponder response. The FAA is issuing this AD to address loss of
transponder when in the presence of CW interference. The unsafe
condition, if not addressed, could result in an un-annunciated loss
of Mode S transponder function and subsequent un-annunciated loss of
traffic collision avoidance system advisory messages, which could
lead to loss of separation from other airplanes and a mid-air
collision.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
Except as specified in paragraph (h) of this AD: At the
applicable times specified in the ``Compliance'' paragraph of Boeing
Alert Requirements Bulletin B787-81205-SB340065-00 RB, Issue 001,
dated February 11, 2025, do all applicable actions identified in,
and in accordance with, the Accomplishment Instructions of Boeing
Alert Requirements Bulletin B787-81205-SB340065-00 RB, Issue 001,
dated February 11, 2025.
Note 1 to paragraph (g): Guidance for accomplishing the actions
required by this AD can be found in Boeing Alert Service Bulletin
B787-81205-SB340065-00, Issue 001, dated February 11, 2025, which is
referred to in Boeing Alert Requirements Bulletin B787-81205-
SB340065-00 RB, Issue 001, dated February 11, 2025.
(h) Exception to Requirements Bulletin Specifications
Where the ``Boeing Recommended Compliance Time (Whichever Occurs
Later)'' column in the table under the ``Compliance'' paragraph of
Boeing Alert Requirements Bulletin B787-81205-SB340065-00 RB, Issue
001, dated February 11, 2025, refers to the Issue 001 date of
Requirements Bulletin B787-81205-SB340065-00 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 Michael Closson,
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA
98198; phone: 206-231-3973; 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 B787-81205-SB340065-00
RB, Issue 001, dated February 11, 2025.
(ii) [Reserved]
(3) For the 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].
[[Page 12071]]
Issued on February 24, 2026.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft
Certification Service.
[FR Doc. 2026-04832 Filed 3-11-26; 8:45 am]
BILLING CODE 4910-13-P