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FROM: THE BOEING COMPANY
TO: Boeing Correspondence (MOM)
[MESSAGE NUMBER:MOM-MOM-21-0089-01B] Multi Operator Message
MESSAGE DATE: 26 Feb 2021 1610 US PACIFIC TIME / 27 Feb 2021
0010 GMT
This message is sent to 777F Customers, Regional Directors,
Regional Managers and Boeing Field Service Bases.
CATEGORY: Maintenance, Engineering, Flight Operations,
Management, Business, Safety, Regulatory
SERVICE REQUEST ID: 3-4995538960
ACCOUNT: Boeing Correspondence (MOM)
DUE DATE: 03-Mar-2021 23:59
PRODUCT TYPE: Airplane
PRODUCT LINE: 777
PRODUCT: 777-F
ATA: 3810-00
SUBJECT: Action - 777 Freighter Water Spillage Into Electrical
Compartment
REFERENCES:
/A/ Attachment_AMM 21-27-02 Figure Sheet 1
/B/ Attachment_AMM 21-27-02 Figure Sheet 2
/C/ Attachment_EE Cooling Air Filter With Water Line Detachment
/D/ Attachment_IPC 21-26 EE Cooling Air Filter
/E/ Attachment_Top Down View
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SUMMARY:
This message provides information and actions related to a
safety issue resulting from a water supply line that detached
above an EE cooling filter, which resulted in water intruding
into the Forward Electronics Equipment Bay (EE Bay).
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DESCRIPTION:
Boeing received a report from an operator of a 777 Freighter
(34,000FH / 6,000FC) that during potable water servicing on
ground, they were notified of an issue by multiple messages
appearing on the Engine Indication and Crew Alert System
(EICAS). Investigation revealed that the swaged end fitting
ferrule of a CRES water supply line had become partially or
fully detached from the tube, causing water to spill onto an EE
cooling filter in the LHS cargo sidewall at STA 571 at Zone 121.
It is unknown how long or how much water was spilled during the
event. The cooling filter became saturated with the water, which
was then blown via the EE Cooling System onto multiple
electronic equipment LRUs located in the EE bay. The operator
removed and replaced the affected equipment. This was the first
reported instance of this issue.
777 Freighters before LN960 do not have a joint in this location
unless Boeing Service Bulletin (SB) 777-38-0042 (WATER/WASTE -
Potable - Change of the Water Distribution And Recirculation
System) was implemented. 777 Freighters at LN960 and after have
a joint at this location from the factory installed CRES tube
assembly.
Boeing has identified this as an airplane safety issue and
anticipates the potential for regulatory action.
Boeing is sharing information via this MOM for the fleet's
awareness and to provide near term preventative action while
terminating action is investigated.
Boeing will provide updates for this issue via Fleet Team Digest
(FTD) Article (777-FTD-38-21001 | Water Spillage Into Electrical
Compartment). The FTD is in work and will be released by 03-
March-2021.
DESIRED ACTION:
==============
Safety Actions:
While terminating action is being investigated, operators of
Boeing 777 Freighter airplanes that are configured with the CRES
MOM-MOM-21-0089 26-Feb-2021
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tube assembly joint located above the EE cooling filter should
implement the following action within 5 days of this MOM
publication.
This action applies to airplanes LN960 and on.
This action also applies to airplanes LN959 and earlier that
have implemented Boeing SB 777-38-0042.
This action does not apply to LN 959 and earlier that have not
implemented Boeing SB 777-38-0042.
1) Deactivate Potable Water System:
Perform deactivation of the potable water system, referring to
Boeing AMM Task 38-10-00-040-801. Deactivation of the potable
water system will remove water from the system, preventing
pressurization, detachment, and potential leakage above the EE
cooling filter.
Strongly Recommended Actions:
1) Potable Water Line Inspection:
Boeing recommends, at earliest convenience, that while the
system is pressurized, operators utilize cargo liner removal,
referring to Boeing AMM Task 25-52-06-000-801, at STA 571 to
gain visual access to the water line above the EE cooling
filter. Perform water leak inspection referring to Boeing AMM
Subtask 38-10-00-790-011 to ensure there are no existing water
leaks in the area. Note: The system can be pressurized during
regular service (prior to deactivation) and during disinfection
procedures.
2) Potable Water System Disinfection & Flush:
Boeing recommends operators perform potable water system
disinfection referring to Boeing AMM Task 38-10-00-600-801 prior
to deactivation of the potable water system to reduce the risk
of bacterial contamination and corrosion while the system
remains deactivated. If an operator elects to perform the
initial deactivation (From Safety Action 1) without performing
the disinfection task, Boeing strongly recommends performing the
disinfection task within 2 weeks of deactivation, which will
require a second application of the deactivation task to redrain
the system following disinfection.
3) Galley Component Deactivation
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In addition to the potable water system being deactivated,
Boeing recommends following deactivation procedures for
equipment listed in AMM Section 25-32 (Galley Equipment) or
pulling the circuit breakers (in addition to collaring the
breakers and add 'INOP' decal) to prevent potable water reliant
appliances from running with no potable water. Operators may
also review the respective Component Maintenance Manuals (CMM)
for any further information on deactivation of individual galley
equipment. Deactivating the water reliant equipment in the
galley can prevent nuisance faults and potentially increased
component maintenance for appliances that use the potable water
system.
Depending on the configuration of the aircraft items such as
coffee maker, steam oven, espresso machine, and water boiler may
be deactivated or removed. Note: Steam ovens will retain partial
functionality without a potable water source by operating in
convection mode.
4) Dry Lav Operational Consideration
When operating with the potable water system deactivated, the
lavatory can continue functioning while dry, as the vacuum
system will still be functional. As an option, operators may
supplement lavatory operations with other sources of water, such
as water bottles, to perform a wet flush in lieu of having the
potable water system active.
5) Cold Weather Operations
Because the reported event occurred while the plane was airplane
in a cold weather environment, Boeing recommends operators
review Boeing AMM Section 12-33 (Cold Weather Maintenance),
specifically Boeing AMM Tasks 12-33-01-660-041 (Cold Weather
Maintenance - Toilets and Potable Water) and 12-33-02-680-001
(Cold Weather Unattended Parking at Temp Below 32F - Potable
Water Drain).
6) Reporting
Boeing requests operators to submit a Service Request through
BCS with any findings of water leakage in the vicinity of the EE
cooling filter at STA 571.
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If attachments are referred to, and are not present, please
access them by logging into MyBoeingFleet Service Request
System. If you have further questions, you may contact the
appropriate Airline Support Manager.
Service Request System:
https://myboeingfleet.boeing.com/bsrs/client/index.html#/momDeta
il/3-2AG3ARV
(Note: MyBoeingFleet portal login is required to access link in
the Service Request System)
Huy Phan - Service Engineering, Payloads Systems
Mutua Munavu - Service Engineering Manager
Customer Support
The Boeing Company
MOM-MOM-21-0089 26-Feb-2021
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AMM 21-27-02 Figure Sheet 1.PNG
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AMM 21-27-02 Figure Sheet 2.PNG
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EE Cooling Air Filter With Water Line Detachment.png
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IPC 21-26 EE Cooling Air Filter.png
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Top Down View.png
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Summary of File(s)
File(s) listed below are included in the PDF:
AMM 21-27-02 Figure Sheet 1.PNG
AMM 21-27-02 Figure Sheet 2.PNG
EE Cooling Air Filter With Water Line Detachment.png
IPC 21-26 EE Cooling Air Filter.png
Top Down View.png
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