[4910-13-P]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-1884; Project Identifier AD-2023-00948-T]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2023-08-04, which applies to certain The Boeing Company Model 787-8, 787-9, and
787-10 airplanes. AD 2023-08-04 requires a detailed visual inspection of all door 1 and
door 3 lavatory and galley potable water systems for any missing or incorrectly installed
clamshell couplings, and applicable on-condition actions. Since the FAA issued AD
2023-08-04, Boeing has discovered that some couplings did not have the required safety
strap and has developed a design solution that replaces the couplings with couplings that
have safety straps to address the unsafe condition. This proposed AD would retain the
requirements of AD 2023-08-04 and require a detailed inspection of all clamshell
couplings for the presence and correct installation of safety straps at door 1 and door 3
lavatories and galleys with a potable water system, and applicable on-condition actions.
The AD would also prohibit the installation of affected parts at inspection locations and
remove Model 787-10 airplanes from the applicability. The FAA is proposing this AD to
address the unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by [INSERT DATE 45
DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].

ADDRESSES: You may send comments, using the procedures found in 14 CFR 11.43
and 11.45, by any of the following methods:
• Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for
submitting comments.
• Fax: 202-493-2251.
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC
20590.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA2024-1884; 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 NPRM, any
comments received, and other information. The street address for Docket Operations is
listed above.
Material Incorporated by Reference:
• For Boeing material identified in this NPRM, 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 by searching for and locating Docket No. FAA-2024-1884.

FOR FURTHER INFORMATION CONTACT: Brandon Lucero, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3569;
email: Brandon.Lucero@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or arguments about
this proposal. Send your comments to an address listed under ADDRESSES. Include
“Docket No. FAA-2024-1884; Project Identifier AD-2023-00948-T” at the beginning of
your comments. The most helpful comments reference a specific portion of the proposal,
explain the reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend this proposal
because of those comments.
Except for Confidential Business Information (CBI) as described in the following
paragraph, and other information as described in 14 CFR 11.35, the FAA will post all
comments received, without change, to regulations.gov, including any personal
information you provide. The agency will also post a report summarizing each
substantive verbal contact received about this NPRM.
Confidential Business Information
CBI is commercial or financial information that is both customarily and actually
treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C.
552), CBI is exempt from public disclosure. If your comments responsive to this NPRM
contain commercial or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to this NPRM, it is
important that you clearly designate the submitted comments as CBI. Please mark each
page of your submission containing CBI as “PROPIN.” The FAA will treat such marked
submissions as confidential under the FOIA, and they will not be placed in the public

docket of this NPRM. Submissions containing CBI should be sent to Brandon Lucero,
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone:
206-231-3569; email: Brandon.Lucero@faa.gov. Any commentary that the FAA receives
that is not specifically designated as CBI will be placed in the public docket for this
rulemaking.
Background
The FAA issued AD 2023-08-04, Amendment 39-22419 (88 FR 33823, May 25,
2023) (AD 2023-08-04), for certain The Boeing Company Model 787-8, 787-9, and
787-10 airplanes. AD 2023-08-04 was prompted by reports of a loss of water pressure
during flight and water leaks that affected multiple pieces of electronic equipment. AD
2023-08-04 requires a detailed visual inspection of all door 1 and door 3 lavatory and
galley potable water systems for any missing or incorrectly installed clamshell couplings,
and applicable on-condition actions. The agency issued AD 2023-08-04 to address
incorrectly installed or missing lavatory and galley clamshell couplings that could lead to
water leaks and water migration to critical flight equipment, which may affect the
continued safe flight and landing of the airplane.
Actions Since AD 2023-08-04 Was Issued
The FAA issued AD 2023-08-04 as an interim action and indicated that the FAA
might consider additional rulemaking. AD 2023-08-04 requires an inspection of the
potable water clamshell couplings, regardless of the safety-strap configuration. Boeing
has determined that some clamshell couplings do not have the required safety straps and
has since developed procedures to ensure that affected clamshell couplings have correctly
installed safety straps. The FAA has now determined that further rulemaking is
necessary, and this proposed AD follows from that determination.

Model 787-10 airplanes, which are all delivered with the safety-strap coupling,
are no longer subject to the unsafe condition, and do not need the new proposed
inspections. Therefore, those airplanes are not included in the applicability.
The FAA is proposing this AD to prevent a loss of water pressure during flight
and water leaks that can affect multiple pieces of electronic equipment. The unsafe
condition, if not addressed, could lead to water migration to critical flight equipment,
which may affect the continued safe flight and landing of the airplane.
FAA’s Determination
The FAA is issuing this NPRM after determining that the unsafe condition
described previously is likely to exist or develop on other products of the same type
design.
Related Material under 1 CFR Part 51
The FAA reviewed Boeing Alert Requirements Bulletin B787-81205-SB25029900 RB, Issue 001, dated July 31, 2023. This material specifies procedures for a detailed
inspection for the presence and correct installation of safety straps at the clamshell
couplings at door 1 and door 3 lavatories and galleys with a potable water system. The
material also specifies applicable on-condition actions including correcting the
installation of the safety strap, replacing any clamshell coupling that does not have a strap
with a new clamshell coupling that has a safety strap, and performing a water leak test.
This proposed AD would also require Boeing Alert Requirements Bulletin
B787-81205-SB380021-00 RB, Issue 001, dated August 12, 2022, which the Director of
the Federal Register approved for incorporation by reference as of June 29, 2023 (88 FR
33823, May 25, 2023).
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 ADDRESSES.

Proposed AD Requirements in this NPRM
This proposed AD would retain all of the requirements of AD 2023-08-04. This
proposed AD would require accomplishing the actions specified in the material already
described, except for any differences identified as exceptions in the regulatory text of this
proposed AD. This proposed AD would also prohibit the installation of affected parts at
inspection locations and remove Model 787-10 airplanes from the applicability. For
information on the procedures and compliance times, see this material at regulations.gov
under Docket No. FAA-2024-1884.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would affect 165
airplanes of U.S. registry. The FAA estimates the following costs to comply with this
proposed AD:
Estimated costs
Action

Labor cost

Parts
cost

Cost per
product

Cost on U.S.
operators

Clamshell coupling
inspection, per lavatory or
galley (retained actions
from AD 2023-08-04)

1 work-hour X
$85 per hour =
$85

$0

$85

$14,025

Safety strap inspection,
per lavatory/galley (new
proposed action)

2 work-hours
X $85 per hour
= $170, per
lavatory/galley

$0

$170, per
lavatory/galley

$28,050

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

On-condition costs
Action

Labor cost

Parts cost

Cost per product

Correct installation for
clamshell coupling with 0.25 work-hour X $85
safety strap that was
per hour = $21.25
installed incorrectly

$0

$21.25

Install clamshell
coupling 14C34-08C

0.25 work-hour X $85
per hour = $21.25

$267

$288.25

Install clamshell
coupling 14C33-08

0.25 work-hour X $85
per hour = $21.25

$47

$68.25

Leak test

0.5 work-hour X $85
per hour = $42.50

$0

$42.50

Authority for this Rulemaking
Title 49 of the United States Code specifies the FAA’s authority to issue rules on
aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator.
Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency’s
authority.
The FAA is issuing this rulemaking under the authority described in Subtitle VII,
Part A, Subpart III, Section 44701: General requirements. Under that section, Congress
charges the FAA with promoting safe flight of civil aircraft in air commerce by
prescribing regulations for practices, methods, and procedures the Administrator finds
necessary for safety in air commerce. This regulation is within the scope of that authority
because it addresses an unsafe condition that is likely to exist or develop on products
identified in this rulemaking action.
Regulatory Findings
The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would not have a
substantial direct effect on the States, on the relationship between the national
Government and the States, or on the distribution of power and responsibilities among the
various levels of government.

For the reasons discussed above, I certify this proposed regulation:
(1) Is not a “significant regulatory action” under Executive Order 12866,
(2) Would not affect intrastate aviation in Alaska, and
(3) Would not have a significant economic impact, positive or negative, on a
substantial number of small entities under the criteria of the Regulatory Flexibility Act.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the Administrator, the FAA
proposes to amend 14 CFR part 39 as follows:
PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
§ 39.13 [Amended]
2. The FAA amends § 39.13 by:
a. Removing Airworthiness Directive (AD) 2023-08-04, Amendment 39-22419
(88 FR 33823, May 25, 2023), and
b. Adding the following new AD:
The Boeing Company: Docket No. FAA-2024-1884; Project Identifier
AD-2023-00948-T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive (AD) by
[INSERT DATE 45 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL
REGISTER].

(b) Affected ADs
This AD replaces AD 2023-08-04, Amendment 39-22419 (88 FR 33823, May 25,
2023) (AD 2023-08-04).
(c) Applicability
This AD applies to The Boeing Company Model 787-8 and 787-9 airplanes,
certificated in any category, as specified in Boeing Alert Requirements Bulletin B78781205-SB380021-00 RB, Issue 001, dated August 12, 2022.
(d) Subject
Air Transport Association (ATA) of America Code 38, Water/waste.
(e) Unsafe Condition
This AD was prompted by reports of a loss of water pressure during flight and
water leaks that affected multiple pieces of electronic equipment. The FAA is issuing this
AD to prevent a loss of water pressure during flight and water leaks that can affect
multiple pieces of electronic equipment. The unsafe condition, if not addressed, could
lead to water leaks and water migration to critical flight equipment, which may affect the
continued safe flight and landing of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Retained Clamshell Coupling Inspection, with No Changes
This paragraph restates the requirements of paragraph (g) of AD 2023-08-04, with
no changes. Except as specified by paragraph (h) of this AD: At the applicable times
specified in the “Compliance” paragraph of Boeing Alert Requirements Bulletin
B787-81205-SB380021-00 RB, Issue 001, dated August 12, 2022, do all applicable
actions identified in, and in accordance with, the Accomplishment Instructions of Boeing
Alert Requirements Bulletin B787-81205-SB380021-00 RB, Issue 001, dated August 12,
2022.

Note 1 to paragraph (g): Guidance for accomplishing the actions required by
paragraph (g) of this AD can be found in Boeing Alert Service Bulletin
B787-81205-SB380021-00, Issue 001, dated August 12, 2022, which is referred to in
Boeing Alert Requirements Bulletin B787-81205-SB380021-00 RB, Issue 001, dated
August 12, 2022.
(h) Retained Exception to Service Information Specifications, With No Changes
This paragraph restates the exceptions of paragraph (h) of AD 2023-08-04, with
no changes. Where the Compliance Time columns of the table in the “Compliance”
paragraph of Boeing Alert Requirements Bulletin B787-81205-SB380021-00 RB,
Issue 001, dated August 12, 2022, refer to the Issue 001 date of Requirements Bulletin
B787-81205-SB380021-00 RB, this AD requires using June 29, 2023 (the effective date
of AD 2023-08-04).
(i) Retained Credit for Previous Actions, with No Changes
This paragraph restates paragraph (i) of AD 2023-08-04, with no changes. This
paragraph provides credit for the actions specified in paragraph (g) of this AD, if those
actions were performed before June 29, 2023 (the effective date of AD 2023-08-04),
using Multi Operator Message MOM-MOM-21-0554-01B, dated December 14, 2021 (for
lavatory inspections); and MOM-MOM-22-0229-01B, dated April 29, 2022 (for galley
inspections).
(j) New Required Actions
For airplanes identified in Boeing Alert Requirements Bulletin B787-81205SB250299-00 RB, Issue 001, dated July 31, 2023: Except as specified by paragraph (k)
of this AD, at the applicable times specified in the “Compliance” paragraph of Boeing
Alert Requirements Bulletin B787-81205-SB250299-00 RB, Issue 001, dated July 31,
2023, do all applicable actions identified in, and in accordance with, the Accomplishment

Instructions of Boeing Alert Requirements Bulletin B787-81205-SB250299-00 RB, Issue
001, dated July 31, 2023.
Note 2 to paragraph (j): Guidance for accomplishing the actions required by this
AD can be found in Boeing Alert Service Bulletin B787-81205-SB250299-00, Issue 001,
dated July 31, 2023, which is referred to in Boeing Alert Requirements Bulletin
B787-81205-SB250299-00 RB, Issue 001, dated July 31, 2023.
(k) New Exception to Service Information Specifications
Where the Compliance Time columns of the tables in the “Compliance”
paragraph of Boeing Alert Requirements Bulletin B787-81205-SB250299-00 RB, Issue
001, dated July 31, 2023, use the phrase “the Issue 001 date of Requirements Bulletin
B787-81205-SB250299-00 RB,” this AD requires using the effective date of this AD.
(l) Terminating Action for Clamshell Coupling Inspection
For the airplanes identified in Boeing Alert Requirements Bulletin B787-81205SB250299-00 RB, Issue 001, dated July 31, 2023: Accomplishment of the actions
required by paragraph (j) of this AD terminates the requirements of paragraph (g) of this
AD.
(m) Parts Installation Prohibition
As of the effective date of this AD, no person may install a clamshell coupling,
part number (P/N) 14C02-08C or P/N AS1655A08, at inspection locations where P/N
14C02-08C or P/N AS1655A08 was replaced with P/N 14C34-08C or P/N 14C33-08 on
any airplane in accordance with Boeing Alert Requirements Bulletin B787-81205SB250299-00 RB, Issue 001, dated July 31, 2023.
(n) 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 (o)(1) of this AD. Information may be emailed to:
AMOC@faa.gov.
(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.
(4) AMOCs approved for AD 2023-08-04 are approved as AMOCs for the
corresponding provisions of Boeing Alert Requirements Bulletin
B787-81205-SB380021-00 RB, Issue 001, dated August 12, 2022, that are required by
paragraph (g) of this AD.
(o) Related Information
(1) For more information about this AD, contact Brandon Lucero, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3569;
email: Brandon.Lucero@faa.gov.
(2) Material identified in this AD that is not incorporated by reference is available
at the addresses specified in paragraph (p)(5) of this AD.

(p) Material Incorporated by Reference
(1) The Director of the Federal Register approved the incorporation by reference
(IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR
part 51.
(2) You must use this material as applicable to do the actions required by this AD,
unless this AD specifies otherwise.
(3) The following material was approved for IBR on [DATE 35 DAYS AFTER
PUBLICATION OF THE FINAL RULE].
(i) Boeing Alert Requirements Bulletin B787-81205-SB250299-00 RB, Issue 001,
dated July 31, 2023.
(ii) [Reserved]
(4) The following material was approved for IBR on June 29, 2023 (88 FR 33823,
May 25, 2023).
(i) Boeing Alert Requirements Bulletin B787-81205-SB380021-00 RB, Issue 001,
dated August 12, 2022.
(ii) [Reserved]
(5) 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.
(6) 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.
(7) 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
fr.inspection@nara.gov.
Issued on July 2, 2024.

Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2024-15235 Filed: 7/12/2024 8:45 am; Publication Date: 7/15/2024]