# Boeing Alert Requirements Bulletin 737-53A1401 RB: No revision named

- Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2021-1169; AD 2022-08-05 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Boeing Alert Requirements Bulletin 737-53A1401 RB](https://openairdocs.org/service-documents/boeing/737-53a1401-rb.md)
- Title as filed: 737-53A1401 RB --BOEING
- Pages: 107
- PDF: https://openairdocs.org/files/sha256/a7/b3/a7b33caafb499b8462da63eaead43df2a152cf2f29d9da9dc7d715509a2fbd3a
- Page: https://openairdocs.org/service-documents/boeing/737-53a1401-rb/file/a7b33caafb49

## Text

Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N.

### Page 1

Commercial 
Airplanes
737
Requirements Bulletin
ALERT
Number: 737-53A1401 RB
Original Issue: April 27, 2021
ATA System: 5321 5232 5261
SUBJECT: FUSELAGE - Passenger Cabin Floors - Main Deck Cargo Compartment and Electrical
and Electronics Compartment Sealant Inspection, Installation, and Replacement
Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15
CFR 300-774). An export license may be required before it is used for development, production or use by foreign
persons from specific countries. The controller of this data has the individual responsibility to abide by all export
laws.
9E991ECCN:
Copyright © 2021 Boeing.
Unpublished Work. All Rights Reserved.
Treatment of this document and its content is governed by contract with Boeing. Rights to use this document
are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The
Boeing Company.
Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner,
BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and
Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in
connection with this document unless provided in writing by Boeing.
Original Issue: April 27, 2021
737-53A1401 RB
1 of 107
3.0

### Page 2

Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
2 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT
BLANK PAGE

### Page 3

Table of Contents
1 . E F F E C T I V I T Y  ................................................ 5
A . A i r p l a n e s  ................................................ 5
B . S p a r e s  A f f e c t e d  ............................................ 6
2. CONCURRENT REQUIREMENTS ..................................... 6
3 . C O M P L I A N C E  ................................................ 6
4. APPROVAL ................................................ 2 0
5. ACCOMPLISHMENT INSTRUCTIONS .................................. 2 1
A. General Information ......................................... 2 1
B. Work Instructions ........................................... 2 3
FIGURE 4: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGHS - INSPECTION . . 40
FIGURE 5: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGHS - INSTALLATION . 42
FIGURE 6: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT INSPECTION .................................... 4 7
FIGURE 7: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT INSPECTION .................................... 4 9
FIGURE 8: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT INSTALLATION .................................. 5 1
FIGURE 9: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT REPLACEMENT .................................. 5 3
FIGURE 10: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN SEAL AT STA 360, LBL 58.89 -
SEALANT INSPECTION .................................... 5 5
FIGURE 11: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN SEAL AT STA 360, LBL 58.89 -
SEALANT INSPECTION .................................... 5 7
FIGURE 12: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN SEAL AT STA 360, LBL 58.89 -
SEALANT INSTALLATION .................................. 5 9
FIGURE 13: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN SEAL AT STA 360, LBL 58.89 -
SEALANT REPLACEMENT .................................. 6 1
FIGURE 14: MAIN DECK CARGO COMPARTMENT FLOOR - FLOOR PANEL AT STA 354, LBL 58.7
ADJACENT TO RCB - INSPECTION ............................. 6 3
FIGURE 15: MAIN DECK CARGO COMPARTMENT FLOOR - FLOOR PANEL AT STA 354, LBL 58.7
ADJACENT TO RCB - INSPECTION ............................. 6 5
FIGURE 16: MAIN DECK CARGO COMPARTMENT FLOOR - FLOOR PANEL AT STA 354, LBL 58.7
ADJACENT TO RCB - SEALANT INSTALLATION ...................... 6 7
FIGURE 17: MAIN DECK CARGO COMPARTMENT FLOOR - FLOOR PANEL AT STA 354, LBL 58.7
ADJACENT TO RCB - SEALANT REPLACEMENT ..................... 6 9
FIGURE 19: MAIN DECK CARGO COMPARTMENT FLOOR - RIGID CARGO BARRIER AND ADJACENT
FLOOR STRUCTURE - SEALANT INSTALLATION ..................... 7 1
FIGURE 20: MAIN DECK CARGO COMPARTMENT FLOOR - FLOOR PANELS AND MOISTURE BARRIER
TAPE INSTALLATION ..................................... 7 5
FIGURE 33: MAIN DECK CARGO COMPARTMENT DOOR - WEATHER SEAL - INSTALLATION . . 80
FIGURE 34: ELECTRICAL AND ELECTRONICS COMPARTMENT - E5 RACK DRAIN PAN SHROUD -
SEALANT INSPECTION [Group 2] .............................. 8 6
FIGURE 35: ELECTRICAL AND ELECTRONICS COMPARTMENT - E5 RACK DRAIN PAN SHROUD -
SEALANT INSPECTION [Group 2] .............................. 9 0
FIGURE 36: ELECTRICAL AND ELECTRONICS COMPARTMENT - E5 RACK DRAIN PAN SHROUD -
SEALANT INSTALLATION [Group 2] ............................. 9 4
FIGURE 37: ELECTRICAL AND ELECTRONICS COMPARTMENT - E5 RACK DRAIN PAN SHROUD -
SEALANT REPLACEMENT [Group 2] ............................ 9 8
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
3 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 4

FIGURE 38: ELECTRICAL AND ELECTRONICS COMPARTMENT - E5 RACK DRAIN PAN SHROUD,
SHROUD RAIL ASSEMBLY, AND SUPPORT RAIL ASSEMBLY - SEALANT INSTALLATION
[Group 2, Configuration 1] .................................. 1 0 2
FIGURE 39: ELECTRICAL AND ELECTRONICS COMPARTMENT - E5 RACK DRAIN PAN SHROUD,
SHROUD RAIL ASSEMBLY, AND SUPPORT RAIL ASSEMBLY - SEALANT INSTALLATION
[Group 2, Configuration 2] .................................. 1 0 5
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
4 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 5

Commercial 
Airplanes
737
Requirements Bulletin
ALERT
Number: 737-53A1401 RB
Original Issue: April 27, 2021
ATA System: 5321 5232 5261
SUBJECT: FUSELAGE - Passenger Cabin Floors - Main Deck Cargo Compartment and Electrical
and Electronics Compartment Sealant Inspection, Installation, and Replacement
THIS DOCUMENT IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN
PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS DOCUMENT
TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS DOCUMENT TO THE
NEW OWNER. THIS IS AN ENHANCED REQUIRED FOR COMPLIANCE DOCUMENT. THE BOEING
PROCESSES USED TO CREATE THE SERVICE BULLETIN (SB) AND THE REQUIREMENTS BULLETIN
(RB) ENSURE THAT THE INFORMATION BETWEEN "RC START" AND "RC END" IN THE SB ARE IDENTICAL
TO THE INFORMATION IN THE SAME SECTIONS (COMPLIANCE, WORK INSTRUCTIONS…) OF THE RB
WHICH THE SB REFERS TO AS THE RELATED DOCUMENT.
1. Effectivity
A. Airplanes
This bulletin is applicable to 737-800 Airplane(s), line number(s) 607, 610, 731, 998, 1002, 1024,
1059, 1110, 1135, 1138, 1163, 1170, 1181, 1184, 1201, 1207, 1212, 1234, 1251, 1444, 1608 in
2 Group(s).
The Variable Numbers and Group Information for the applicable airplanes is given below.
DESCRIPTIONCONFIGURATIONGROUP
737-800 Boeing Converted Freighter (BCF) airplanes without airstairs
that were modified through Boeing Service Bulletin (SB) 737-00-1025.
-1
737-800 BCF airplanes with airstairs that were modified through
Boeing SB 737-00-1023 or SB 737-00-1025.
-2
737-800 BCF airplanes that have not accomplished SB 737-25-1660.1
737-800 BCF airplanes that have accomplished SB 737-25-1660.2
Airplane Models:
737-800
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
5 of 107

### Page 6

GroupVariable Number
2YC921 - YC922
2YC972 - YC973
2YC977
1YD101
1YD311 - YD313
GroupVariable Number
1YD316
1YD320
1YD322
1YD324 - YD326
1YD328 - YD330
GroupVariable Number
1YD334
2YJ001
2YJ011
--
--
B. Spares Affected
None.
2. CONCURRENT REQUIREMENTS
None.
3. COMPLIANCE
The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to
Requirements Bulletin 737-53A1401 RB. The Airworthiness Directive will make the compliance tasks and
times given in Requirements Bulletin 737-53A1401 RB mandatory.
Accomplish the required actions, based on the applicable conditions in Tables 1, 2, and 3, in accordance
with Accomplishment Instructions.
When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When
more than one ACTION is given for a CONDITION or an OPTION, do all of the ACTION numbers for that
CONDITION or OPTION.
Group 1:
Table 1: Main Deck Cargo Compartment Sealant Inspection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
On the main deck cargo com-
partment floor, adjacent to the
Rigid Cargo Barrier (RCB), do
a detailed inspection of the
drain troughs for any surface
dents or scratches.
All Airplanes
-Before further flight.Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 1: ANY
SURFACE DENTS
GREATER THAN 0.10
INCHES IN DEPTH OR
SCRATCHES
GREATER THAN 0.02
INCHES IN DEPTH
FOUND ON ANY
DRAIN TROUGH
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
6 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 7

Group 1:
Table 1: Main Deck Cargo Compartment Sealant Inspection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before further flight.Install drain troughs and apply
sealant.
CONDITION 2: NO
SURFACE DENTS,
AND NO SCRATCHES
FOUND, OR ANY
SURFACE DENTS
LESS THAN OR
EQUAL TO 0.10 INCH-
ES IN DEPTH AND
SCRATCHES LESS
THAN OR EQUAL TO
0.02 INCHES IN
DEPTH FOUND ON
ANY DRAIN TROUGH
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do a detailed inspection of the
drain trough at Left Buttock
Line (LBL) 58.89 for missing
sealant.
All Airplanes
-Before further flight.Apply sealant to the drain
trough.
CONDITION 3: NO
SEALANT FOUND ON
THE DRAIN TROUGH
-Before further flight.Do a detailed inspection of the
sealant at the drain trough at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 4:
SEALANT FOUND ON
THE DRAIN TROUGH
-Before further flight.CONDITION 4.1 (ACTION 1):
Remove all sealant from the
drain trough.
CONDITION 4.1:
SEALANT ON THE
DRAIN TROUGH
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CON-
TINUOUS
-Before further flight.CONDITION 4.1 (ACTION 2):
Apply sealant to the drain
trough.
--No further action.CONDITION 4.2:
SEALANT ON THE
DRAIN TROUGH
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING AND NOT
PEELING
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do a detailed inspection of the
drain seal at LBL 58.89 for
missing sealant.
All Airplanes
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
7 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 8

Group 1:
Table 1: Main Deck Cargo Compartment Sealant Inspection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before further flight.Apply sealant to the drain seal.CONDITION 5: NO
SEALANT FOUND ON
THE DRAIN SEAL
-Before further flight.Do a detailed inspection of the
sealant at the drain seal at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 6:
SEALANT FOUND ON
THE DRAIN SEAL
-Before further flight.CONDITION 6.1 (ACTION 1):
Remove all sealant from the
drain seal.
CONDITION 6.1:
SEALANT ON THE
DRAIN SEAL FOUND
FLAKING, PEELING,
OR NOT SMOOTH
AND CONTINUOUS
-Before further flight.CONDITION 6.1 (ACTION 2):
Apply sealant to the drain seal.
--No further action.CONDITION 6.2:
SEALANT ON THE
DRAIN SEAL FOUND
SMOOTH AND CON-
TINUOUS, NOT FLAK-
ING, AND NOT PEEL-
ING
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do a detailed inspection of the
main deck cargo compartment
floor panel joints at STA 354,
LBL 58.7 adjacent to the RCB
for missing sealant.
All Airplanes
-Before further flight.Apply sealant to the floor pan-
el joints.
CONDITION 7: NO
SEALANT FOUND ON
THE FLOOR PANEL
JOINTS
-Before further flight.Do a detailed inspection of the
sealant at the floor panel joints
at STA 354, LBL 58.7 adjacent
to the RCB for smooth contin-
uous sealant application, flak-
ing, and peeling.
CONDITION 8:
SEALANT FOUND ON
ANY FLOOR PANEL
JOINT
-Before further flight.CONDITION 8.1 (ACTION 1):
Remove all sealant from the
floor panel joints.
CONDITION 8.1:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CON-
TINUOUS
-Before further flight.CONDITION 8.1 (ACTION 2):
Apply sealant to the floor pan-
el joints.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
8 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 9

Group 1:
Table 1: Main Deck Cargo Compartment Sealant Inspection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
--No further action.CONDITION 8.2:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING, AND NOT
PEELING
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Between the RCB and the ad-
jacent floor structure, apply
sealant into any gaps and
mouse holes, until flush with
aft face of the RCB.
All Airplanes
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Between the RCB and STA
380, apply sealant on the floor
panel joints, install moisture
barrier tape on the floor panels
and install waterseal tape be-
tween the RCB and adjacent
floor structure.
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Install new Main Deck Cargo
Door (MDCD) weather seal.
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do the Floor Water Leak Test.
(a)
-Before further flight.Do a detailed inspection of
sealant at all locations speci-
fied in this Requirements Bul-
letin for missing, peeling, or
flaking sealant.
CONDITION 9: MORE
THAN 4 OUNCES OF
WATER COLLECTS IN
ANY ELECTRICAL
AND ELECTRONICS
(EE) COMPARTMENT
DRIP SHIELD
-Before further flight.CONDITION 9.1 (ACTION 1):
Reapply sealant at affected
location(s).
CONDITION 9.1:
MISSING, PEELING,
OR FLAKING
SEALANT FOUND -Before further flight.CONDITION 9.1 (ACTION 2):
Repeat the Floor Water Leak
Test until no more than 4
ounces of water collects on
any drip shield. (a)(b)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
9 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 10

Group 1:
Table 1: Main Deck Cargo Compartment Sealant Inspection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before further flight.Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 10: RE-
PEATED ATTEMPTS
DOES NOT RESULT
IN 4 OR LESS
OUNCES OF WATER
FROM COLLECTING
ON ANY EE COM-
PARTMENT DRIP
SHIELD
(a) The Floor Water Leak Test is defined as: Make sure the airplane is parked on level surface or
up to 5 degrees nose-down attitude. On the forward main deck cargo compartment floor, from
STA 460, LBL 25 seat track, empty 3 gallons minimum of potable water in the forward direction
between BL 0 to LBL 55. Empty an additional 3 gallons minimum of potable water in the forward
direction between BL 0 and RBL 55. Wait a minimum of five minutes.
Four ounces or less of water in any Electrical and Electronics (EE) compartment drip shield is
acceptable.
(b) Repeat the test no more than 6 times.
Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
On the main cargo compart-
ment floor, adjacent to the
Rigid Cargo Barrier (RCB), do
a detailed inspection of the
drain troughs for any surface
dents or scratches.
All Airplanes
-Before further flight.Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 1: ANY
SURFACE DENTS
GREATER THAN 0.10
INCHES IN DEPTH OR
SCRATCHES
GREATER THAN 0.02
INCHES IN DEPTH
FOUND ON ANY
DRAIN TROUGH
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
10 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 11

Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before further flight.Install drain troughs and apply
sealant.
CONDITION 2: NO
SURFACE DENTS,
AND NO SCRATCHES
FOUND, OR ANY
SURFACE DENTS
LESS THAN OR
EQUAL TO 0.10 INCH-
ES IN DEPTH AND
SCRATCHES LESS
THAN OR EQUAL TO
0.02 INCHES IN
DEPTH FOUND ON
ANY DRAIN TROUGH
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do a detailed inspection of the
drain trough at Left Buttock
Line (LBL) 58.89 for missing
sealant.
All Airplanes
-Before further flight.Apply sealant to the drain
trough.
CONDITION 3: NO
SEALANT FOUND ON
THE DRAIN TROUGH
-Before further flight.Do a detailed inspection of the
sealant at the drain trough at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 4:
SEALANT FOUND ON
THE DRAIN TROUGH
-Before further flight.CONDITION 4.1 (ACTION 1):
Remove all sealant from the
drain trough.
CONDITION 4.1:
SEALANT ON THE
DRAIN TROUGH
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CON-
TINUOUS
-Before further flight.CONDITION 4.1 (ACTION 2):
Apply sealant to the drain
trough.
--No further action.CONDITION 4.2:
SEALANT ON THE
DRAIN TROUGH
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING, AND NOT
PEELING
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
11 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 12

Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do a detailed inspection of the
drain seal at LBL 58.89 for
missing sealant.
All Airplanes
-Before further flight.Apply sealant to the drain seal.CONDITION 5: NO
SEALANT FOUND ON
THE DRAIN SEAL
-Before further flight.Do a detailed inspection of the
sealant at the drain seal at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 6:
SEALANT FOUND ON
THE DRAIN SEAL
-Before further flight.CONDITION 6.1 (ACTION 1):
Remove all sealant from the
drain seal.
CONDITION 6.1:
SEALANT ON THE
DRAIN SEAL FOUND
FLAKING, PEELING,
OR NOT SMOOTH
AND CONTINUOUS
-Before further flight.CONDITION 6.1 (ACTION 2):
Apply sealant to the drain seal.
--No further action.CONDITION 6.2:
SEALANT ON THE
DRAIN SEAL FOUND
SMOOTH AND CON-
TINUOUS, NOT FLAK-
ING, AND NOT PEEL-
ING
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do a detailed inspection of the
main deck cargo compartment
floor panel joints at STA 354,
LBL 58.7 adjacent to the RCB
for missing sealant.
All Airplanes
-Before further flight.Apply sealant to the floor pan-
el joints.
CONDITION 7: NO
SEALANT FOUND ON
THE FLOOR PANEL
JOINTS
-Before further flight.Do a detailed inspection of the
sealant at the floor panel joints
at STA 354, LBL 58.7 adjacent
to the RCB for smooth contin-
uous sealant application, flak-
ing, and peeling.
CONDITION 8:
SEALANT FOUND ON
ANY FLOOR PANEL
JOINT
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
12 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 13

Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
Before further flight.CONDITION 8.1 (ACTION 1):
Remove all sealant from the
floor panel joints.
CONDITION 8.1:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CON-
TINUOUS
Before further flight.CONDITION 8.1 (ACTION 2):
Apply sealant to the floor pan-
el joints.
--No further action.CONDITION 8.2:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING, AND NOT
PEELING
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Between the RCB and the ad-
jacent floor structure, apply
sealant into any gaps and
mouse holes, until flush with
aft face of the RCB.
All Airplanes
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Between the RCB and STA
380, apply sealant on the floor
panel joints, install moisture
barrier tape on the floor pan-
els, and install waterseal tape
between the RCB and adja-
cent floor structure.
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Install new Main Deck Cargo
Door (MDCD) weather seal.
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do a detailed inspection of the
E5 Rack drain pan shroud for
missing sealant.
-Before further flight.Apply sealant to the E5 Rack
drain pan shroud.
CONDITION 9: NO
SEALANT FOUND ON
THE E5 RACK DRAIN
PAN SHROUD
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
13 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 14

Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before further flight.Do a detailed inspection of the
sealant at the E5 Rack drain
pan shroud for smooth contin-
uous sealant application, flak-
ing, and peeling.
CONDITION 10:
SEALANT FOUND ON
THE E5 RACK DRAIN
PAN SHROUD
-Before further flight.CONDITION 10.1 (ACTION
1): Remove all sealant from
the E5 Rack drain pan shroud.
CONDITION 10.1:
SEALANT ON THE E5
RACK DRAIN PAN
SHROUD FOUND
FLAKING, PEELING,
OR NOT SMOOTH
AND CONTINUOUS
-Before further flight.CONDITION 10.1 (ACTION
2): Apply sealant to the E5
Rack drain pan shroud.
--No further action.CONDITION 10.2:
SEALANT ON THE E5
RACK DRAIN PAN
SHROUD FOUND
SMOOTH AND CON-
TINUOUS, NOT FLAK-
ING, AND NOT PEEL-
ING
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Apply sealant between the E5
Rack drain pan shroud rail as-
sembly and support rail assem-
bly, and apply sealant to fas-
teners and nutplates.
All Airplanes
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do the Floor Water Leak Test.
(a)
-Before further flight.Do a detailed inspection of
sealant at all locations speci-
fied in this Requirements Bul-
letin for missing, peeling, or
flaking sealant.
CONDITION 11: MORE
THAN 4 OUNCES OF
WATER COLLECTS IN
ANY ELECTRICAL
AND ELECTRONICS
(EE) COMPARTMENT
DRIP SHIELD
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
14 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 15

Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before further flight.CONDITION 11.1 (ACTION
1): Reapply sealant at affected
location(s).
CONDITION 11.1:
MISSING, PEELING,
OR FLAKING
SEALANT FOUND -Before further flight.CONDITION 11.1 (ACTION
2): Repeat the Floor Water
Leak Test until no more than
4 ounces of water collects on
any drip shield. (a)(b)
-Before further flight.Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 12: RE-
PEATED ATTEMPTS
DOES NOT RESULT
IN 4 OR LESS
OUNCES OF WATER
FROM COLLECTING
ON ANY EE COM-
PARTMENT DRIP
SHIELD
(a) The Floor Water Leak Test is defined as: Make sure the airplane is parked on level surface or
up to 5 degrees nose-down attitude. On the forward main deck cargo compartment floor, from
STA 460, LBL 25 seat track, empty 3 gallons minimum of potable water in the forward direction
between BL 0 to LBL 55. Empty an additional 3 gallons minimum of potable water in the forward
direction between BL 0 and RBL 55. Wait a minimum of five minutes.
Four ounces or less of water in any Electrical and Electronics (EE) compartment drip shield is
acceptable.
(b) Repeat the test no more than 6 times.
Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
On the main cargo compart-
ment floor, adjacent to the
Rigid Cargo Barrier (RCB), do
a detailed inspection of the
drain troughs for any surface
dents or scratches.
All Airplanes
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
15 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 16

Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before further flight.Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 1: ANY
SURFACE DENTS
GREATER THAN 0.10
INCHES IN DEPTH OR
SCRATCHES
GREATER THAN 0.02
INCHES IN DEPTH
FOUND ON ANY
DRAIN TROUGH
-Before further flight.Install drain troughs and apply
sealant.
CONDITION 2: NO
SURFACE DENTS,
AND NO SCRATCHES
FOUND, OR ANY
SURFACE DENTS
LESS THAN OR
EQUAL TO 0.10 INCH-
ES IN DEPTH AND
SCRATCHES LESS
THAN OR EQUAL TO
0.02 INCHES IN
DEPTH FOUND ON
ANY DRAIN TROUGH
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do a detailed inspection of the
drain trough at Left Buttock
Line (LBL) 58.89 for missing
sealant.
All Airplanes
-Before further flight.Apply sealant to the drain
trough.
CONDITION 3: NO
SEALANT FOUND ON
THE DRAIN TROUGH
-Before further flight.Do a detailed inspection of the
sealant at the drain trough at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 4:
SEALANT FOUND ON
THE DRAIN TROUGH
-Before further flight.CONDITION 4.1 (ACTION 1):
Remove all sealant from the
drain trough.
CONDITION 4.1:
SEALANT ON THE
DRAIN TROUGH
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CON-
TINUOUS
-Before further flight.CONDITION 4.1 (ACTION 2):
Apply sealant to the drain
trough.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
16 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 17

Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
--No further action.CONDITION 4.2:
SEALANT ON THE
DRAIN TROUGH
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING, AND NOT
PEELING
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do a detailed inspection of the
drain seal at LBL 58.89 for
missing sealant.
All Airplanes
-Before further flight.Apply sealant to the drain seal.CONDITION 5: NO
SEALANT FOUND ON
THE DRAIN SEAL
-Before further flight.Do a detailed inspection of the
sealant at the drain seal at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 6:
SEALANT FOUND ON
THE DRAIN SEAL
-Before further flight.CONDITION 6.1 (ACTION 1):
Remove all sealant from the
drain seal.
CONDITION 6.1:
SEALANT ON THE
DRAIN SEAL FOUND
FLAKING, PEELING,
OR NOT SMOOTH
AND CONTINUOUS
-Before further flight.CONDITION 6.1 (ACTION 2):
Apply sealant to the drain seal.
--No further action.CONDITION 6.2:
SEALANT ON THE
DRAIN SEAL FOUND
SMOOTH AND CON-
TINUOUS, NOT FLAK-
ING, AND NOT PEEL-
ING
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do a detailed inspection of the
main deck cargo compartment
floor panel joints at STA 354,
LBL 58.7 adjacent to the RCB
for missing sealant.
All Airplanes
-Before further flight.Apply sealant to the floor pan-
el joints.
CONDITION 7: NO
SEALANT FOUND ON
THE FLOOR PANEL
JOINTS
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
17 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 18

Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before further flight.Do a detailed inspection of the
sealant at the floor panel joints
at STA 354, LBL 58.7 adjacent
to the RCB for smooth contin-
uous sealant application, flak-
ing, and peeling.
CONDITION 8:
SEALANT FOUND ON
ANY FLOOR PANEL
JOINT
Before further flight.CONDITION 8.1 (ACTION 1):
Remove all sealant from the
floor panel joints.
CONDITION 8.1:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CON-
TINUOUS
Before further flight.CONDITION 8.1 (ACTION 2):
Apply sealant to the floor pan-
el joints.
--No further action.CONDITION 8.2:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING, AND NOT
PEELING
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Between the RCB and the ad-
jacent floor structure, apply
sealant into any gaps and
mouse holes, until flush with
aft face of the RCB.
All Airplanes
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Between the RCB and STA
380, apply sealant on the floor
panel joints, install moisture
barrier tape on the floor pan-
els, and install waterseal tape
between the RCB and adja-
cent floor structure.
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Install new Main Deck Cargo
Door (MDCD) weather seal.
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do a detailed inspection of the
E5 Rack drain pan shroud for
missing sealant.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
18 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 19

Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before further flight.Apply sealant to the E5 Rack
drain pan shroud.
CONDITION 9: NO
SEALANT FOUND ON
THE E5 RACK DRAIN
PAN SHROUD
-Before further flight.Do a detailed inspection of the
sealant at the E5 Rack drain
pan shroud for smooth contin-
uous sealant application, flak-
ing, and peeling.
CONDITION 10:
SEALANT FOUND ON
THE E5 RACK DRAIN
PAN SHROUD
-Before further flight.CONDITION 10.1 (ACTION
1): Remove all sealant from
the E5 Rack drain pan shroud.
CONDITION 10.1:
SEALANT ON THE E5
RACK DRAIN PAN
SHROUD FOUND
FLAKING, PEELING,
OR NOT SMOOTH
AND CONTINUOUS
-Before further flight.CONDITION 10.1 (ACTION
2): Apply sealant to the E5
Rack drain pan shroud.
--No further action.CONDITION 10.2:
SEALANT ON THE E5
RACK DRAIN PAN
SHROUD FOUND
SMOOTH AND CON-
TINUOUS, NOT FLAK-
ING, AND NOT PEEL-
ING
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Apply sealant between the E5
Rack drain pan shroud rail as-
sembly and support rail assem-
bly, and apply sealant to fas-
teners and nutplates.
All Airplanes
-Within 12 months after
the Original Issue date
of Requirements Bul-
letin 737-53A1401 RB.
Do the Floor Water Leak Test.
(a)
-Before further flight.Do a detailed inspection of
sealant at all locations speci-
fied in this Requirements Bul-
letin for missing, peeling, or
flaking sealant.
CONDITION 11: MORE
THAN 4 OUNCES OF
WATER COLLECTS IN
ANY ELECTRICAL
AND ELECTRONICS
(EE) COMPARTMENT
DRIP SHIELD
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
19 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 20

Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant In-
spection, Installation, and Replacement
Repeat Interval
(Not to Exceed)
Compliance TimeActionCondition
-Before further flight.CONDITION 11.1 (ACTION
1): Reapply sealant at affected
location(s).
CONDITION 11.1:
MISSING, PEELING,
OR FLAKING
SEALANT FOUND -Before further flight.CONDITION 11.1 (ACTION
2): Repeat the Floor Water
Leak Test until no more than
4 ounces of water collects on
any drip shield. (a)(b)
-Before further flight.Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 12: RE-
PEATED ATTEMPTS
DOES NOT RESULT
IN 4 OR LESS
OUNCES OF WATER
FROM COLLECTING
ON ANY EE COM-
PARTMENT DRIP
SHIELD
(a) The Floor Water Leak Test is defined as: Make sure the airplane is parked on level surface or
up to 5 degrees nose-down attitude. On the forward main deck cargo compartment floor, from
STA 460, LBL 25 seat track, empty 3 gallons minimum of potable water in the forward direction
between BL 0 to LBL 55. Empty an additional 3 gallons minimum of potable water in the forward
direction between BL 0 and RBL 55. Wait a minimum of five minutes.
Four ounces or less of water in any Electrical and Electronics (EE) compartment drip shield is
acceptable.
(b) Repeat the test no more than 6 times.
4. APPROVAL
This Requirements Bulletin was examined by the Federal Aviation Administration (FAA). The changes
specified in this document comply with the applicable regulations and are FAA approved, as well as European
Union Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved
airplanes listed in the service bulletin effectivity. This document and its approval were based on the airplane
in its original Boeing delivery configuration or as modified by other Boeing changes.
If an airplane has a non-Boeing modification or repair that affects a component or system also affected by
this Requirements Bulletin, the operator is responsible for obtaining appropriate regulatory agency approval
before incorporating this Requirements Bulletin.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
20 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 21

5.    ACCOMPLISHMENT INSTRUCTIONS
A. GENERAL INFORMATION
NOTE: 1. This is an Enhanced Required for Compliance document. There will be a separate
Service Bulletin (SB) and a separate Requirements Bulletin (RB). If an RB is mandated
by an Airworthiness Directive (AD), then all applicable requirements specified in the
RB must be done. For the related SB, some locations are marked RC Start and RC
End to identify the requirements that are restated from the RB. For the related SB,
the areas between RC Start and RC End, including sub-steps and any figures
identified between RC Start and RC End, must be done to comply with the AD.
Therefore, an Alternative Method of Compliance (AMOC) is required for any deviations
to steps between RC Start and RC End, including substeps and identified figures.
For the related SB, the steps not between RC Start and RC End may be deviated
from using accepted methods in accordance with the operator's maintenance or
inspection program without obtaining approval of an AMOC; this is provided that the
steps between RC Start and RC End, including sub-steps and identified figures, can
still be done as specified, and the airplane can be put back in an airworthy condition.
Figures not required for compliance are omitted from the RB.
2. This is an Enhanced Required for Compliance document. The Boeing processes
used to create the Service Bulletin (SB) and the Requirements Bulletin (RB) ensure
that the information between "RC Start" and "RC End" in the SB are identical to the
information in the same sections (Compliance, Work Instructions...) of the RB which
the SB refers to as the related document.
3. The compliance times for the actions in WORK INSTRUCTIONS are in Compliance.
4. Unless shown differently, these dimensions and tolerances are used:
– Linear dimensions are in inches
– Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus
or minus 0.03 inch
– Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch
– Angular tolerance is plus or minus 2 degrees
– Hole dimensions for standard solid rivets and fasteners are in Structural Repair
Manual (SRM) Chapter 51
– Torque Values:
— Values for structural fasteners are given in 737 Structural Repair Manual,
Chapter 51.
— Values for airframe maintenance tasks are included in Chapter 20 of 737
Aircraft Maintenance Manual (AMM).
— Values for electrical maintenance tasks are included in Chapter 20 of
Standard Wiring Practices Manual (SWPM).
— Values for engine maintenance tasks are included in Chapter 70 of 737
Aircraft Maintenance Manual (AMM).
— Non-standard torque values for maintenance tasks are included in the
applicable installation step.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
21 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 22

5. These work instructions refer to procedures included in other Boeing documents.
When the words "refer to" are used and the operator has an accepted alternative
procedure, the accepted alternative procedure can be used. When the words "in
accordance with" are included in the instruction, the procedure in the Boeing document
must be used.
6. When more than one OPTION is given for a CONDITION, do only one of the OPTION
numbers. When more than one ACTION is given for a CONDITION or an OPTION,
do all of the ACTION numbers for that CONDITION or OPTION.
7. A Detailed Inspection is defined as: An intensive examination of a specific item,
installation or assembly to detect damage, failure or irregularity. This could include
tactile assessment in which a component or assembly can be checked for
tightness/security. Available lighting is normally supplemented with a direct source
of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors
and magnifying lenses may be necessary. Surface cleaning and elaborate access
procedures may be required.
8. Where the work instructions include installation of a kept part, a new or serviceable
part with the same part number can be installed as an alternative to the kept part.
9. If it is necessary to remove more parts for access, you can remove those parts. If
you can get access without removing identified parts, it is not necessary to remove
all of the identified parts. Jacking and shoring limitations must be observed.
10. Use the approved fastener, process and material substitutions in accordance with
SRM Chapter 51.
11. If the length of any fastener specified in this service bulletin does not meet installation
standards given in SRM Chapter 51, then a fastener of the same specification, or
an approved substitute, with a length which meets the installation standards given
in SRM Chapter 51 may be used. In addition, washers may be installed for fastener
grip length in accordance with SRM Chapter 51. Refer to SOPM 20-50-01 for alternate
full threaded fasteners (screws) needed for installation in this service bulletin.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
22 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 23

B. WORK INSTRUCTIONS
Actions Required for Compliance
1. Requirements:
Group 1:
Table 1: Main Deck Cargo Compartment Sealant Inspection, Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
PART 1: Drain
Trough Removal and
Clean.
-On the main deck cargo com-
partment floor, adjacent to the
Rigid Cargo Barrier (RCB), do
a detailed inspection of the
drain troughs for any surface
dents or scratches.
All Airplanes
-FIGURE 4
--Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 1: ANY
SURFACE DENTS
GREATER THAN 0.10
INCHES IN DEPTH OR
SCRATCHES GREATER
THAN 0.02 INCHES IN
DEPTH FOUND ON ANY
DRAIN TROUGH
-FIGURE 5Install drain troughs and apply
sealant.
CONDITION 2: NO
SURFACE DENTS, AND
NO SCRATCHES
FOUND, OR ANY SUR-
FACE DENTS LESS
THAN OR EQUAL TO
0.10 INCHES IN DEPTH
AND SCRATCHES LESS
THAN OR EQUAL TO
0.02 INCHES IN DEPTH
FOUND ON ANY DRAIN
TROUGH
PART 2: Connect
Drain Trough Drain
Lines.
-
-FIGURE 6Do a detailed inspection of the
drain trough at Left Buttock
Line (LBL) 58.89 for missing
sealant.
All Airplanes
-FIGURE 8Apply sealant to the drain
trough.
CONDITION 3: NO
SEALANT FOUND ON
THE DRAIN TROUGH
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
23 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 24

Group 1:
Table 1: Main Deck Cargo Compartment Sealant Inspection, Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
-FIGURE 7Do a detailed inspection of the
sealant at the drain trough at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 4:
SEALANT FOUND ON
THE DRAIN TROUGH
-FIGURE 9CONDITION 4.1 (ACTION 1):
Remove all sealant from the
drain trough.
CONDITION 4.1:
SEALANT ON THE
DRAIN TROUGH
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CONTIN-
UOUS
CONDITION 4.1 (ACTION 2):
Apply sealant to the drain
trough.
--No further action.CONDITION 4.2:
SEALANT ON THE
DRAIN TROUGH
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING, AND NOT
PEELING
-FIGURE 10Do a detailed inspection of the
drain seal at LBL 58.89 for
missing sealant.
All Airplanes
-FIGURE 12Apply sealant to the drain seal.CONDITION 5: NO
SEALANT FOUND ON
THE DRAIN SEAL
-FIGURE 11Do a detailed inspection of the
sealant at the drain seal at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 6:
SEALANT FOUND ON
THE DRAIN SEAL
-FIGURE 13CONDITION 6.1 (ACTION 1):
Remove all sealant from the
drain seal.
CONDITION 6.1:
SEALANT ON THE
DRAIN SEAL FOUND
FLAKING, PEELING, OR
NOT SMOOTH AND
CONTINUOUS
CONDITION 6.1 (ACTION 2):
Apply sealant to drain seal.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
24 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 25

Group 1:
Table 1: Main Deck Cargo Compartment Sealant Inspection, Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
--No further action.CONDITION 6.2:
SEALANT ON THE
DRAIN SEAL FOUND
SMOOTH AND CONTIN-
UOUS, NOT FLAKING,
AND NOT PEELING
-FIGURE 14Do a detailed inspection of the
main deck cargo compartment
floor panels joints at STA 354,
LBL 58.7 adjacent to the RCB
for missing sealant.
All Airplanes
-FIGURE 16Apply sealant to the floor pan-
el joints.
CONDITION 7: NO
SEALANT FOUND ON
THE FLOOR PANEL
JOINTS
-FIGURE 15Do a detailed inspection of the
sealant at the floor panel joints
at STA 354, LBL 58.7 adjacent
to the RCB for smooth contin-
uous sealant application, flak-
ing, and peeling.
CONDITION 8:
SEALANT FOUND ON
ANY FLOOR PANEL
JOINT
-FIGURE 17CONDITION 8.1 (ACTION 1):
Remove all sealant from the
floor panel joints.
CONDITION 8.1:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CONTIN-
UOUS
CONDITION 8.1 (ACTION 2):
Apply sealant to the floor pan-
el joints.
--No further action.CONDITION 8.2:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING, AND NOT
PEELING
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
25 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 26

Group 1:
Table 1: Main Deck Cargo Compartment Sealant Inspection, Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
-FIGURE 19Between the RCB and the ad-
jacent floor structure, apply
sealant into any gaps and
mouse holes, until flush with
aft face of the RCB.
All Airplanes
-FIGURE 20Between the RCB and STA
380, apply sealant on the floor
panel joints, install moisture
barrier tape on the floor panels
and install waterseal tape be-
tween the RCB and adjacent
floor structure.
PART 3: Drain Water
System Leak Test.
-
PART 4: Seat Track
Splices Sealant In-
spection.
PART 5: Seat Track
Filler Installation.
PART 6: Main Deck
Cargo Compartment
Floor Panels Be-
tween STA 380 and
STA 480 Sealant In-
spection.
PART 7: Main Deck
Cargo Door Weather
Seal Removal.
-FIGURE 33Install new Main Deck Cargo
Door (MDCD) weather seal.
PART 8: Floor Water
Leak Test.
-Do the Floor Water Leak Test.
(a)
--Do a detailed inspection of
sealant at all locations speci-
fied in this Requirements Bul-
letin for missing, peeling, or
flaking sealant.
CONDITION 9: MORE
THAN 4 OUNCES OF
WATER COLLECTS IN
ANY ELECTRICAL AND
ELECTRONICS (EE)
COMPARTMENT DRIP
SHIELD
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
26 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 27

Group 1:
Table 1: Main Deck Cargo Compartment Sealant Inspection, Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
--CONDITION 9.1 (ACTION 1):
Reapply sealant at affected
location(s).
CONDITION 9.1: MISS-
ING, PEELING, OR
FLAKING SEALANT
FOUND --CONDITION 9.1 (ACTION 2):
Repeat the Floor Water Leak
Test until no more than 4
ounces of water collects on
any drip shield. (a)(b)
--Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 10: RE-
PEATED ATTEMPTS
DOES NOT RESULT IN
4 OR LESS OUNCES OF
WATER FROM COL-
LECTING ON ANY EE
COMPARTMENT DRIP
SHIELD
PART 9: MDCD Wa-
ter Spray Functional
Test.
--All Airplanes
PART 10: Cargo
Handling System
Parts and Anti-Skid
Tape Installation.
--
(a) The Floor Water Leak Test is defined as: Make sure the airplane is parked on level surface or up to 5
degrees nose-down attitude. On the forward main deck cargo compartment floor, from STA 460, LBL 25
seat track, empty 3 gallons minimum of potable water in the forward direction between BL 0 to LBL 55.
Empty an additional 3 gallons minimum of potable water in the forward direction between BL 0 and RBL
55. Wait a minimum of five minutes.
Four ounces or less of water in any Electrical and Electronics (EE) compartment drip shield is acceptable.
(b) Repeat the test no more than 6 times.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
27 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 28

Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
PART 1: Drain
Trough Removal and
Clean.
-On the main cargo compart-
ment floor, adjacent to the
Rigid Cargo Barrier (RCB), do
a detailed inspection of the
drain troughs for any surface
dents or scratches.
All Airplanes
-FIGURE 4
--Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 1: ANY
SURFACE DENTS
GREATER THAN 0.10
INCHES IN DEPTH OR
SCRATCHES GREATER
THAN 0.02 INCHES IN
DEPTH FOUND ON ANY
DRAIN TROUGH
-FIGURE 5Install drain troughs and apply
sealant.
CONDITION 2: NO
SURFACE DENTS, AND
NO SCRATCHES
FOUND, OR ANY SUR-
FACE DENTS LESS
THAN OR EQUAL TO
0.10 INCHES IN DEPTH
AND SCRATCHES LESS
THAN OR EQUAL TO
0.02 INCHES IN DEPTH
FOUND ON ANY DRAIN
TROUGH
PART 2: Connect
Drain Trough Drain
Lines.
-
-FIGURE 6Do a detailed inspection of the
drain trough at Left Buttock
Line (LBL) 58.89 for missing
sealant.
All Airplanes
-FIGURE 8Apply sealant to the drain
trough.
CONDITION 3: NO
SEALANT FOUND ON
THE DRAIN TROUGH
-FIGURE 7Do a detailed inspection of the
sealant at the drain trough at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 4:
SEALANT FOUND ON
THE DRAIN TROUGH
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
28 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 29

Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
-FIGURE 9CONDITION 4.1 (ACTION 1):
Remove all sealant from the
drain trough.
CONDITION 4.1:
SEALANT ON THE
DRAIN TROUGH
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CONTIN-
UOUS
CONDITION 4.1 (ACTION 2):
Apply sealant to the drain
trough.
--No further action.CONDITION 4.2:
SEALANT ON THE
DRAIN TROUGH
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING, AND NOT
PEELING
-FIGURE 10Do a detailed inspection of the
drain seal at LBL 58.89 for
missing sealant.
All Airplanes
-FIGURE 12Apply sealant to the drain seal.CONDITION 5: NO
SEALANT FOUND ON
THE DRAIN SEAL
-FIGURE 11Do a detailed inspection of the
sealant at the drain seal at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 6:
SEALANT FOUND ON
THE DRAIN SEAL
-FIGURE 13CONDITION 6.1 (ACTION 1):
Remove all sealant from the
drain seal.
CONDITION 6.1:
SEALANT ON THE
DRAIN SEAL FOUND
FLAKING, PEELING, OR
NOT SMOOTH AND
CONTINUOUS
CONDITION 6.1 (ACTION 2):
Apply sealant to drain seal.
--No further action.CONDITION 6.2:
SEALANT ON THE
DRAIN SEAL FOUND
SMOOTH AND CONTIN-
UOUS, NOT FLAKING,
AND NOT PEELING
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
29 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 30

Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
-FIGURE 14Do a detailed inspection of the
main deck cargo compartment
floor panel joints at STA 354,
LBL 58.7 adjacent to the RCB
for missing sealant.
All Airplanes
-FIGURE 16Apply sealant to the floor pan-
el joints.
CONDITION 7: NO
SEALANT FOUND ON
THE FLOOR PANEL
JOINTS
-FIGURE 15Do a detailed inspection of the
sealant at the floor panel joints
at STA 354, LBL 58.7 adjacent
to the RCB for smooth contin-
uous sealant application, flak-
ing, and peeling.
CONDITION 8:
SEALANT FOUND ON
ANY FLOOR PANEL
JOINT
-FIGURE 17CONDITION 8.1 (ACTION 1):
Remove all sealant from the
floor panel joints.
CONDITION 8.1:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CONTIN-
UOUS
CONDITION 8.1 (ACTION 2):
Apply sealant to the floor pan-
el joints.
--No further action.CONDITION 8.2:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING, AND NOT
PEELING
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
30 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 31

Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
-FIGURE 19Between the RCB and the ad-
jacent floor structure, apply
sealant into any gaps and
mouse holes, until flush with
aft face of the RCB.
All Airplanes
-FIGURE 20Between the RCB and STA
380, apply sealant on the floor
panel joints, install moisture
barrier tape on the floor pan-
els, and install waterseal tape
between the RCB and adja-
cent floor structure.
PART 3: Drain Water
System Leak Test.
-
PART 4: Seat Track
Splices Sealant In-
spection.
PART 5: Seat Track
Filler Installation.
PART 6: Main Deck
Cargo Compartment
Floor Panels Be-
tween STA 380 and
STA 480 Sealant In-
spection.
PART 7: Main Deck
Cargo Door Weather
Seal Removal.
-FIGURE 33Install new Main Deck Cargo
Door (MDCD) weather seal.
-FIGURE 34Do a detailed inspection of the
E5 Rack drain pan shroud for
missing sealant.
-FIGURE 36Apply sealant to the E5 Rack
drain pan shroud.
CONDITION 9: NO
SEALANT FOUND ON
THE E5 RACK DRAIN
PAN SHROUD
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
31 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 32

Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
-FIGURE 35Do a detailed inspection of the
sealant at the E5 Rack drain
pan shroud for smooth contin-
uous sealant application, flak-
ing, and peeling.
CONDITION 10:
SEALANT FOUND ON
THE E5 RACK DRAIN
PAN SHROUD
-FIGURE 37CONDITION 10.1 (ACTION
1): Remove all sealant from
the E5 Rack drain pan shroud.
CONDITION 10.1:
SEALANT ON THE E5
RACK DRAIN PAN
SHROUD FOUND
FLAKING, PEELING, OR
NOT SMOOTH AND
CONTINUOUS
CONDITION 10.1 (ACTION
2): Apply sealant to the E5
Rack drain pan shroud.
--No further action.CONDITION 10.2:
SEALANT ON THE E5
RACK DRAIN PAN
SHROUD FOUND
SMOOTH AND CONTIN-
UOUS, NOT FLAKING,
AND NOT PEELING
-FIGURE 38Apply sealant between the E5
Rack drain pan shroud rail as-
sembly and support rail assem-
bly, and apply sealant to fas-
teners and nutplates.
All Airplanes
PART 8: Floor Water
Leak Test.
-Do the Floor Water Leak Test.
(a)
--Do a detailed inspection of
sealant at all locations speci-
fied in this Requirements Bul-
letin for missing, peeling, or
flaking sealant.
CONDITION 11: MORE
THAN 4 OUNCES OF
WATER COLLECTS IN
ANY ELECTRICAL AND
ELECTRONICS (EE)
COMPARTMENT DRIP
SHIELD
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
32 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 33

Group 2, Configuration 1:
Table 2: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
--CONDITION 11.1 (ACTION
1): Reapply sealant at affected
location(s).
CONDITION 11.1: MISS-
ING, PEELING, OR
FLAKING SEALANT
FOUND --CONDITION 11.1 (ACTION
2): Repeat the Floor Water
Leak Test until no more than
4 ounces of water collects on
any drip shield.
--Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 12: RE-
PEATED ATTEMPTS
DOES NOT RESULT IN
4 OR LESS OUNCES OF
WATER FROM COL-
LECTING ON ANY EE
COMPARTMENT DRIP
SHIELD
PART 9: MDCD Wa-
ter Spray Functional
Test.
--All Airplanes
PART 10: Cargo
Handling System
Parts and Anti-Skid
Tape Installation.
--
(a) The Floor Water Leak Test is defined as: Make sure the airplane is parked on level surface or up to 5
degrees nose-down attitude. On the forward main deck cargo compartment floor, from STA 460, LBL 25
seat track, empty 3 gallons minimum of potable water in the forward direction between BL 0 to LBL 55.
Empty an additional 3 gallons minimum of potable water in the forward direction between BL 0 and RBL
55. Wait a minimum of five minutes.
Four ounces or less of water in any Electrical and Electronics (EE) compartment drip shield is acceptable.
(b) Repeat the test no more than 6 times.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
33 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 34

Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
PART 1: Drain
Trough Removal and
Clean.
-On the main cargo compart-
ment floor, adjacent to the
Rigid Cargo Barrier (RCB), do
a detailed inspection of the
drain troughs for any surface
dents or scratches.
All Airplanes
-FIGURE 4
--Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 1: ANY
SURFACE DENTS
GREATER THAN 0.10
INCHES IN DEPTH OR
SCRATCHES GREATER
THAN 0.02 INCHES IN
DEPTH FOUND ON ANY
DRAIN TROUGH
-FIGURE 5Install drain troughs and apply
sealant.
CONDITION 2: NO
SURFACE DENTS, AND
NO SCRATCHES
FOUND, OR ANY SUR-
FACE DENTS LESS
THAN OR EQUAL TO
0.10 INCHES IN DEPTH
AND SCRATCHES LESS
THAN OR EQUAL TO
0.02 INCHES IN DEPTH
FOUND ON ANY DRAIN
TROUGH
PART 2: Connect
Drain Trough Drain
Lines.
-
-FIGURE 6Do a detailed inspection of the
drain trough at Left Buttock
Line (LBL) 58.89 for missing
sealant.
All Airplanes
-FIGURE 8Apply sealant to the drain
trough.
CONDITION 3: NO
SEALANT FOUND ON
THE DRAIN TROUGH
-FIGURE 7Do a detailed inspection of the
sealant at the drain trough at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 4:
SEALANT FOUND ON
THE DRAIN TROUGH
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
34 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 35

Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
-FIGURE 9CONDITION 4.1 (ACTION 1):
Remove all sealant from the
drain trough.
CONDITION 4.1:
SEALANT ON THE
DRAIN TROUGH
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CONTIN-
UOUS
CONDITION 4.1 (ACTION 2):
Apply sealant to the drain
trough.
--No further action.CONDITION 4.2:
SEALANT ON THE
DRAIN TROUGH
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING, AND NOT
PEELING
-FIGURE 10Do a detailed inspection of the
drain seal at LBL 58.89 for
missing sealant.
All Airplanes
-FIGURE 12Apply sealant to the drain seal.CONDITION 5: NO
SEALANT FOUND ON
THE DRAIN SEAL
-FIGURE 11Do a detailed inspection of the
sealant at the drain seal at
LBL 58.89 for smooth continu-
ous sealant application, flak-
ing, and peeling.
CONDITION 6:
SEALANT FOUND ON
THE DRAIN SEAL
-FIGURE 13CONDITION 6.1 (ACTION 1):
Remove all sealant from the
drain seal.
CONDITION 6.1:
SEALANT ON THE
DRAIN SEAL FOUND
FLAKING, PEELING, OR
NOT SMOOTH AND
CONTINUOUS
CONDITION 6.1 (ACTION 2):
Apply sealant to drain seal.
--No further action.CONDITION 6.2:
SEALANT ON THE
DRAIN SEAL FOUND
SMOOTH AND CONTIN-
UOUS, NOT FLAKING,
AND NOT PEELING
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
35 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 36

Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
-FIGURE 14Do a detailed inspection of the
main deck cargo compartment
floor panel joints at STA 354,
LBL 58.7 adjacent to the RCB
for missing sealant.
All Airplanes
-FIGURE 16Apply sealant to the floor pan-
el joints.
CONDITION 7: NO
SEALANT FOUND ON
THE FLOOR PANEL
JOINTS
-FIGURE 15Do a detailed inspection of the
sealant at the floor panel joints
at STA 354, LBL 58.7 adjacent
to the RCB for smooth contin-
uous sealant application, flak-
ing, and peeling.
CONDITION 8:
SEALANT FOUND ON
ANY FLOOR PANEL
JOINT
-FIGURE 17CONDITION 8.1 (ACTION 1):
Remove all sealant from the
floor panel joints.
CONDITION 8.1:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND FLAKING,
PEELING, OR NOT
SMOOTH AND CONTIN-
UOUS
CONDITION 8.1 (ACTION 2):
Apply sealant to the floor pan-
el joints.
--No further action.CONDITION 8.2:
SEALANT ON THE
FLOOR PANEL JOINT
FOUND SMOOTH AND
CONTINUOUS, NOT
FLAKING, AND NOT
PEELING
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
36 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 37

Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
-FIGURE 19Between the RCB and the ad-
jacent floor structure, apply
sealant into any gaps and
mouse holes, until flush with
aft face of the RCB.
All Airplanes
-FIGURE 20Between the RCB and STA
380, apply sealant on the floor
panel joints, install moisture
barrier tape on the floor pan-
els, and install waterseal tape
between the RCB and adja-
cent floor structure.
PART 3: Drain Water
System Leak Test.
-
PART 4: Seat Track
Splices Sealant In-
spection.
PART 5: Seat Track
Filler Installation.
PART 6: Main Deck
Cargo Compartment
Floor Panels Be-
tween STA 380 and
STA 480 Sealant In-
spection.
PART 7: Main Deck
Cargo Door Weather
Seal Removal.
-FIGURE 33Install new Main Deck Cargo
Door (MDCD) weather seal.
-FIGURE 34Do a detailed inspection of the
E5 Rack drain pan shroud for
missing sealant.
-FIGURE 36Apply sealant to the E5 Rack
drain pan shroud.
CONDITION 9: NO
SEALANT FOUND ON
THE E5 RACK DRAIN
PAN SHROUD
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
37 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 38

Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
-FIGURE 35Do a detailed inspection of the
sealant at the E5 Rack drain
pan shroud for smooth contin-
uous sealant application, flak-
ing, and peeling.
CONDITION 10:
SEALANT FOUND ON
THE E5 RACK DRAIN
PAN SHROUD
-FIGURE 37CONDITION 10.1 (ACTION
1): Remove all sealant from
the E5 Rack drain pan shroud.
CONDITION 10.1:
SEALANT ON THE E5
RACK DRAIN PAN
SHROUD FOUND
FLAKING, PEELING, OR
NOT SMOOTH AND
CONTINUOUS
CONDITION 10.1 (ACTION
2): Apply sealant to the E5
Rack drain pan shroud.
--No further action.CONDITION 10.2:
SEALANT ON THE E5
RACK DRAIN PAN
SHROUD FOUND
SMOOTH AND CONTIN-
UOUS, NOT FLAKING,
AND NOT PEELING
-FIGURE 39Apply sealant between the E5
Rack drain pan shroud rail as-
sembly and support rail assem-
bly, and apply sealant to fas-
teners and nutplates.
All Airplanes
PART 8: Floor Water
Leak Test.
-Do the Floor Water Leak Test.
(a)
--Do a detailed inspection of
sealant at all locations speci-
fied in this Requirements Bul-
letin for missing, peeling, or
flaking sealant.
CONDITION 11: MORE
THAN 4 OUNCES OF
WATER COLLECTS IN
ANY ELECTRICAL AND
ELECTRONICS (EE)
COMPARTMENT DRIP
SHIELD
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
38 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 39

Group 2, Configuration 2:
Table 3: Main Deck Cargo Compartment and Electrical and Electronics Compartment Sealant Inspection,
Installation, and Replacement
Refer to the listed
procedures in SB
737-53A1401 Origi-
nal Issue or later
approved revisions
as an accepted pro-
cedure.
Method of ComplianceActionCondition
--CONDITION 11.1 (ACTION
1): Reapply sealant at affected
location(s).
CONDITION 11.1: MISS-
ING, PEELING, OR
FLAKING SEALANT
FOUND --CONDITION 11.1 (ACTION
2): Repeat the Floor Water
Leak Test until no more than
4 ounces of water collects on
any drip shield.
--Contact The Boeing Company
for repair instructions and do
the repair.
CONDITION 12: RE-
PEATED ATTEMPTS
DOES NOT RESULT IN
4 OR LESS OUNCES OF
WATER FROM COL-
LECTING ON ANY EE
COMPARTMENT DRIP
SHIELD
PART 9: MDCD Wa-
ter Spray Functional
Test.
--All Airplanes
PART 10: Cargo
Handling System
Parts and Anti-Skid
Tape Installation.
--
(a) The Floor Water Leak Test is defined as: Make sure the airplane is parked on level surface or up to 5
degrees nose-down attitude. On the forward main deck cargo compartment floor, from STA 460, LBL 25
seat track, empty 3 gallons minimum of potable water in the forward direction between BL 0 to LBL 55.
Empty an additional 3 gallons minimum of potable water in the forward direction between BL 0 and RBL
55. Wait a minimum of five minutes.
Four ounces or less of water in any Electrical and Electronics (EE) compartment drip shield is acceptable.
(b) Repeat the test no more than 6 times.
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
39 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 40 (OCR)

REQUIREMENTS BULLETIN 737-53A1401
ALERT  ALERT
4 LOCATIONS (TYPICAL)
2945571
FIGURE 4: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGHS - INSPECTION
(SHEET 1 OF 2)
Original Issue: April 27, 2021
Export Controlled ECCN: 9E991  Copyright © Unpublished  737-53A1401 RB
Work - See page 1 for details.  40 of 107

### Page 41

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1841A7801-116DRAIN TROUGHInspect1
(a)1841A7801-118DRAIN TROUGHInspect
(a)1841A7801-120DRAIN TROUGHInspect
(a)1841A7801-122DRAIN TROUGHInspect
(a)1841A7801-124DRAIN TROUGHInspect
(a)1841A7801-126DRAIN TROUGHInspect
(a) Do a detailed inspection of the drain troughs for any surface dents or scratches.
FIGURE 4: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGHS - INSPECTION
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
41 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 42 (OCR)

REQUIREMENTS BULLETIN 737-53A1401
ALERT  ALERT
STA
480
STA
340
4 LOCATIONS  6 LOCATIONS  6 LOCATIONS
• LBL  • LBL  LBL
47.35  33.03  8.20
6 LOCATIONS  6 LOC  CATIONS  4 LOCATIONS
11)  13
RBL  RBL  RBL
48.46  29.00
FORWARD MAIN DECK CARGO COMPARTMENT FLOOR  2945699
FIGURE 5: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGHS - INSTALLATION
(SHEET 1 OF 5)
Original Issue: April 27, 2021
Export Controlled ECCN: 9E991
Work - See page 1 for details.  Copyright © Unpublished  COLLO ZE

### Page 43 (OCR)

REQUIREMENTS BULLETIN 737-53A1401
ALERT  ALERT
SEAT TRACK  SEAT TRACK
DRAIN TROUGH
INBD
TYPICAL
A-A
0.09-1  DRAIN TROUGH
0.03
SEAT TRACK
INBD
TYPICAL
2945706
FIGURE 5: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGHS - INSTALLATION
(SHEET 2 OF 5)
Original Issue: April 27, 2021
Export Controlled ECCN: 9E991  Copyright © Unpublished  737-53A1401 RB
Work - See page 1 for details.  43 of 107

### Page 44 (OCR)

REQUIREMENTS BULLETIN 737-53A1401
ALERT  ALERT
0.50
1.50
B
TYPICAL
- DRAIN TROUGH
B-B  2945572
FIGURE 5: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGHS - INSTALLATION
(SHEET 3 OF 5)
Original Issue: April 27, 2021
Export Controlled ECCN: 9E991  737-53A1401 RB
Copyright © Unpublished
Work - See page 1 for details.  44 of 107

### Page 45

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)-BMS5-95, CLASS B-1/2 (BMS5-95,
CLASS B-2 optional)
SEALANTApply1
1841A7801-116DRAIN TROUGHInstall (Kept)2
(b)(f)-BMS5-95, CLASS B-1/2 (BMS5-95,
CLASS B-2 optional)
SEALANTApply
4-FASTENERInstall (Kept)3
(c)-BMS5-95, CLASS B-2SEALANTApply
1841A7801-118DRAIN TROUGHInstall (Kept)4
(b)(f)-BMS5-95, CLASS B-1/2 (BMS5-95,
CLASS B-2 optional)
SEALANTApply
6-FASTENERInstall (Kept)5
(c)-BMS5-95, CLASS B-2SEALANTApply
1841A7801-120DRAIN TROUGHInstall (Kept)6
(b)(f)-BMS5-95, CLASS B-1/2 (BMS5-95,
CLASS B-2 optional)
SEALANTApply
6-FASTENERInstall (Kept)7
(c)-BMS5-95, CLASS B-2SEALANTApply
1841A7801-122DRAIN TROUGHInstall (Kept)8
(b)(f)-BMS5-95, CLASS B-1/2 (BMS5-95,
CLASS B-2 optional)
SEALANTApply
6-FASTENERInstall (Kept)9
(c)-BMS5-95, CLASS B-2SEALANTApply
1841A7801-124DRAIN TROUGHInstall (Kept)10
(b)(f)-BMS5-95, CLASS B-1/2 (BMS5-95,
CLASS B-2 optional)
SEALANTApply
6-FASTENERInstall (Kept)11
(c)-BMS5-95, CLASS B-2SEALANTApply
1841A7801-126DRAIN TROUGHInstall (Kept)12
(b)(f)-BMS5-95, CLASS B-1/2 (BMS5-95,
CLASS B-2 optional)
SEALANTApply
4-FASTENERInstall (Kept)13
(c)-BMS5-95, CLASS B-2SEALANTApply
FIGURE 5: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGHS - INSTALLATION
(SHEET 4 OF 5)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
45 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 46

More DataQtyIdentificationNameTaskStep
(d)12841A7801-100DRAIN SEALInstall (Kept)14
(e)(f)(g)-BMS5-95, CLASS B-1/2 (BMS5-95,
CLASS B-2 or BMS5-142, CLASS B-
1/2 or BMS5-142, CLASS B-2 option-
al)
SEALANTApply
(a) Before installation, prepack the inner surfaces on both ends of each drain trough, between 0.50 inches
and 1.50 inches in length. Total quantity 6 drain troughs.
(b) Apply a faying surface seal to the complete faying surface of the drain trough and all mating surfaces.
Refer to SOPM 20-50-19 as an accepted procedure. Make sure that sealant squeeze out shows continu-
ously along the complete edge of the fay seal joints.
(c) Install fasteners wet with sealant. Refer to SOPM 20-50-19 as an accepted procedure.
(d) Align the forward edge of the drain seal with the forward rib of the drain trough.
(e) Apply a fillet seal on the drain trough edge, drain seal edge, and adjacent seat track edge. Refer to SOPM
20-50-19 as an accepted procedure.
(f) Apply 20 lbs. of distributed weight to the drain troughs and drain seals to ensure sealant adhesion.
(g) Make sure that the sealant has cured before connecting the drain trough drain lines.
FIGURE 5: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGHS - INSTALLATION
(SHEET 5 OF 5)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
46 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 47 (OCR)

REQUIREMENTS BULLETIN 737-53A1401
ALERT  ALERT
STA
OPE
STA
08t
LBL
58.89
STA
360
FORWARD MAIN DECK CARGO
FLOOR DRAIN SYSTEM
FLOOR PANEL
STA —  360
DRAIN TROUGH
• DRAIN SEAL
SHEAR PANEL
LBL  SEAT TRACK
58.89
INSPECTION AREA
A-A  2945711
FIGURE 6: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT INSPECTION
(SHEET 1 OF 2)
Original Issue: April 27, 2021
Export Controlled ECCN: 9E991  737-53A1401 RB
Copyright © Unpublished
Work - See page 1 for details.  47 of 107

### Page 48

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1841A7801-114DRAIN TROUGHInspect1
(a) Do a detailed inspection of the drain trough for missing sealant.
FIGURE 6: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT INSPECTION
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
48 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 49 (OCR)

REQUIREMENTS BULLETIN 737-53A1401
ALERT  ALERT
340
STA
480
LBL
58.89
STA
360
FORWARD MAIN DECK CARGO
FLOOR DRAIN SYSTEM
FLOOR PANEL
DRAIN TROUGH
* DRAIN SEAL
SHEAR PANEL
LBL  SEAT TRACK
58.89
INSPECTION AREA
A-A
FIGURE 7: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT INSPECTION
(SHEET 1 OF 2)
Original Issue: April 27, 2021
Export Controlled ECCN: 9E991  737-53A1401 RB
Copyright © Unpublished
Work - See page 1 for details.  49 of 107

### Page 50

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1841A7801-114DRAIN TROUGHInspect1
(a) Do a detailed inspection of the sealant at the drain trough.
FIGURE 7: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT INSPECTION
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
50 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 51 (OCR)

REQUIREMENTS BULLETIN 737-53A1401
ALERT  ALERT
STA
340
STA
480
LBL
58.89
STA
360
FORWARD MAIN DECK CARGO
FLOOR DRAIN SYSTEM
FLOOR PANEL
DRAIN TROUGH
• DRAIN SEAL
SHEAR PANEL
LBL  SEAT TRACK
58.89
A-A
FIGURE 8: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT INSTALLATION
(SHEET 1 OF 2)
Original Issue: April 27, 2021
Export Controlled ECCN: 9E991  Copyright © Unpublished  737-53A1401 RB
Work - See page 1 for details.  51 of 107

### Page 52

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1841A7801-114DRAIN TROUGHClean1
(b)(c)-BMS5-95, CLASS B-
1/2 (BMS5-95, CLASS
B-2 or BMS5-142,
CLASS B-1/2 or BMS5-
142, CLASS B-2 option-
al)
SEALANTApply2
(a) Solvent clean drain trough edge. Refer to SOPM 20-30-03 as an accepted procedure.
(b) Apply a fillet seal on the drain trough edge. Refer to SOPM 20-50-19 as an accepted procedure.
(c) Make sure that the sealant has cured before connecting the drain trough drain lines.
FIGURE 8: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT INSTALLATION
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
52 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 53 (OCR)

REQUIREMENTS BULLETIN 737-53A1401
ALERT  ALERT
VIS
340
STA
480
LBL
58.89
STA
360
FORWARD MAIN DECK CARGO
FLOOR DRAIN SYSTEM
FLOOR PANEL
DRAIN TROUGH
• DRAIN SEAL
SHEAR PANEL
LBL  SEAT TRACK
58.89
A-A
FIGURE 9: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT REPLACEMENT
(SHEET 1 OF 2)
Original Issue: April 27, 2021
Export Controlled ECCN: 9E991  737-53A1401 RB
Copyright © Unpublished
Work - See page 1 for details.  53 of 107

### Page 54

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)--SEALANTRemove1
(b)(c)-BMS5-95, CLASS B-1/2 (BMS5-95,
CLASS B-2 or BMS5-142, CLASS B-1/2
or BMS5-142, CLASS B-2 optional)
SEALANTApply2
(a) Remove sealant from the drain trough edge. Solvent clean. Refer to SOPM 20-30-03 as an accepted
procedure.
(b) Apply sealant on the drain trough edge. Refer to SOPM 20-50-19 as an accepted procedure.
(c) Make sure that the sealant has cured before the moisture barrier tape is installed.
FIGURE 9: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN TROUGH AT STA 360, LBL 58.89 -
SEALANT REPLACEMENT
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
54 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 55 (OCR)

REQUIREMENTS BULLETIN 737-53A1401
ALERT  ALERT
STA
340
STA
480
LBL
58.89
STA
360
FORWARD MAIN DECK CARGO
FLOOR DRAIN SYSTEM
FLOOR PANEL
STA —  360
DRAIN TROUGH
* DRAIN SEAL
SHEAR PANEL
LBL  • SEAT TRACK
58.89
INSPECTION AREA
A-A
FIGURE 10: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN SEAL AT STA 360, LBL 58.89 -
SEALANT INSPECTION
(SHEET 1 OF 2)
Original Issue: April 27, 2021
Export Controlled ECCN: 9E991  Copyright © Unpublished  737-53A1401 RB
Work - See page 1 for details.  55 of 107

### Page 56

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1841A7801-100DRAIN SEALInspect1
(a) Do a detailed inspection of the drain seal for missing sealant.
FIGURE 10: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN SEAL AT STA 360, LBL 58.89 -
SEALANT INSPECTION
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
56 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 57 (OCR)

REQUIREMENTS BULLETIN 737-53A1401
ALERT  ALERT
STA
340
STA
480
LBL
58.89
STA
360
FORWARD MAIN DECK CARGO
FLOOR DRAIN SYSTEM
FLOOR PANEL
DRAIN TROUGH
* DRAIN SEAL
SHEAR PANEL
LBL  SEAT TRACK
58.89
INSPECTION AREA
A-A
FIGURE 11: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN SEAL AT STA 360, LBL 58.89 -
SEALANT INSPECTION
(SHEET 1 OF 2)
Original Issue: April 27, 2021
Export Controlled ECCN: 9E991  737-53A1401 RB
Copyright © Unpublished
Work - See page 1 for details.  57 of 107

### Page 58

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1841A7801-100DRAIN SEALInspect1
(a) Do a detailed inspection of the sealant at the drain seal.
FIGURE 11: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN SEAL AT STA 360, LBL 58.89 -
SEALANT INSPECTION
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
58 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

### Page 59 (OCR)

REQUIREMENTS BULLETIN 737-53A1401
ALERT  ALERT
STA
340
STA
480
LBL
58.89
STA
360
FORWARD MAIN DECK CARGO
FLOOR DRAIN SYSTEM
FLOOR PANEL
DRAIN TROUGH
•
• DRAIN SEAL
SHEAR PANEL
LBL  SEAT TRACK
58.89
A-A
FIGURE 12: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN SEAL AT STA 360, LBL 58.89 -
SEALANT INSTALLATION
(SHEET 1 OF 2)
Original Issue: April 27, 2021
Export Controlled ECCN: 9E991  737-53A1401 RB
Copyright © Unpublished
Work - See page 1 for details.  59 of 107

### Page 60

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1841A7801-100DRAIN SEALClean1
(b)(c)(d)-BMS5-95, CLASS B-
1/2 (BMS5-95, CLASS
B-2 or BMS5-142,
CLASS B-1/2 or BMS5-
142, CLASS B-2 option-
al)
SEALANTApply2
(a) Solvent clean drain seal. Refer to SOPM 20-30-03 as an accepted procedure.
(b) Align the forward edge of the drain seal with the forward rib of the drain trough.
(c) Apply a fillet seal on the drain seal edge, and adjacent seat track edge. Refer to SOPM 20-50-19 as an
accepted procedure.
(d) Make sure that the sealant has cured before connecting the drain trough drain lines.
FIGURE 12: MAIN DECK CARGO COMPARTMENT FLOOR - DRAIN SEAL AT STA 360, LBL 58.89 -
SEALANT INSTALLATION
(SHEET 2 OF 2)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: April 27, 2021
737-53A1401 RB
60 of 107
REQUIREMENTS BULLETIN 737-53A1401
ALERTALERT

The text continues at https://openairdocs.org/service-documents/boeing/737-53a1401-rb/file/a7b33caafb49.md?from=61

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.