# Boeing Alert Service Bulletin 747-21A2422: Revision 2

- Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2010-0275; AD 2010-14-01 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.
- Document: [Boeing Alert Service Bulletin 747-21A2422](https://openairdocs.org/service-documents/boeing/747-21a2422.md)
- Title as filed: Boeing Service Bulletin
- Pages: 46
- PDF: https://openairdocs.org/files/sha256/84/cc/84ccce27fe1156dfeb75d95c336629626575b8c691eeca057742fed04e213956
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### Page 1

August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 1 of 46
 
 
 
Commercial
Airplane
Group 747
Service Bulletin
Number: 747-21A2422
Date: August 21, 2003
Revision 2: November 16, 2006
ATA System: 2122
SUBJECT: AIR CONDITIONING - Distribution - Duct Insulation, BMS 8-39 Foam, Replacement
BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET
Copyright © 2003 The Boeing Company
Unpublished Work - All Rights Reserved
Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable 
subject matter.  Boeing also claims copyright in this document as a compilation and/or collective work.
This document includes proprietary information owned by The Boeing Company and/or one or more third 
parties.  Treatment of the document and the information it contains is governed by contract with Boeing.  For 
more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124.
Boeing, 707, 717, 727, 737, 747, 757, 767, 777, BBJ, BOEING BUSINESS JET, DC-8, DC-9, DC-10, MD-10, 
MD-11, MD-80, MD-90, the Boeing logo and the Boeing livery are among the trademarks owned by Boeing or 
its subsidiaries. No intellectual property license (express or implied) is granted in connection with this document 
or otherwise.

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### Page 3

Table of Contents
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 3 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
 
Table of Contents
Revision Transmittal Sheet .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 5
Summary .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 7
1. PLANNING INFORMATION .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 9
A. Effectivity .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 9
1. Airplanes   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 9
2. Spares Affected .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  20
B. Concurrent Requirements  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .   .  20
C. Reason .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  21
D. Description .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  22
E. Compliance.  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .   .  .  .  .  22
F. Approval .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  22
G. Manpower   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .   .  .  .  .  22
H. Weight and Balance Changes  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  23
I. Electrical Load Data  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .   .  .  .  23
J. References .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .   .  .  .  .  23
1. Existing Data: .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  23
2. Data supplied with this Service Bulletin:   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  23
3. Installation Drawings Used in the Preparation of this Service Bulletin: .  .  .  .  .  .  .  .  .  .  23
4. Process Data: .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .   .  24
K. Publications Affected .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  24
L. Interchangeability and Intermixability of Parts  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  24
2. MATERIAL INFORMATION .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  25
A. Material - Price and Availability.  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  25
B. Industry Support Information .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .   .  25
C. Parts Necessary For Each Airplane  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  26
1. Kits/Parts: .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  26
2. Parts and Materials Supplied by the Operator:  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  27
3. Parts Modified and Reidentified:   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  27
4. Parts Removed and Not Replaced: .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  28
D. Parts Necessary to Change Spares  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  28
E. Special Tooling - Price and Availability.  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .   28
F. Special Tooling Necessary to do this Service Bulletin .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  28
3. ACCOMPLISHMENT INSTRUCTIONS .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  29
A. GENERAL INFORMATION   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  29
B. WORK INSTRUCTIONS .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  29
FIGURE  1:   DUCT ACCESS, ALL AIRPLANE GROUPS .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  30
FIGURE  2:   DUCT ASSEMBLY REWORK, GROUP 1 AIRPLANES .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  32
FIGURE  3:   DUCT ASSEMBLY REWORK, GROUP 2 AIRPLANES .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  34
FIGURE  4:   DUCT ASSEMBLY REWORK, GROUP 3 AIRPLANES .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  36
FIGURE  5:   DUCT ASSEMBLY REWORK, GROUP 4 AIRPLANES .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  38
APPENDIX  A:   PROCESS DATA - APPLICATION OF BMS 8-300 BY TAPING WITH BMS 5-157 TAPE.
40
APPENDIX  B:   BAC 5412 METHOD VII - BONDING DUCT JOINTS.  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  45
APPENDIX  C:   BAC 5412 METHOD VIII - TAPED TELESCOPING JOINTS.  .  .  .  .  .  .  .  .  .  .  .  .  .  46

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Table of Contents
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August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 5 of 46
 
 
 
Commercial
Airplane
Group 747
Service Bulletin
Number: 747-21A2422 Revision Transmittal Sheet
Date: August 21, 2003
Revision 2: November 16, 2006
ATA System: 2122
SUBJECT: AIR CONDITIONING - Distribution - Duct Insulation, BMS 8-39 Foam, Replacement
This Revision includes all pages of the service bulletin.
COMPLIANCE INFORMATION RELATED TO THIS REVISION
More work is necessary on airplanes changed as shown in the initial release or Revision 01 of this service 
bulletin, if accomplished after September 02, 2005.  If the intent of this Revision 02 was accomplished after 
September 02, 2005, then no more work is required.
REASON FOR REVISION
This revision is sent to give operators approval to use BMS 5-157 tape instead of the non-compliant BMS 5-149 
tape.  This change gives operators new instructions to apply BMS 8-300 insulation to the Environmental Control 
System (ECS) ducts with BMS 5-157 tape.  The BMS 5-157 tape must fully cover the BMS 8-300 insulation. The 
new configuration for the ECS duct insulation meets the flammability requirements of 14CFR 25.856(a), 
Amendment 111.  Airplanes that have the intent of this service bulletin done after September 02, 2005, must 
satisfy the new requirements by fully covering the brown hypalon cover of the BMS 8-300 insulation with BMS 
5-157 tape.
Changes to this service bulletin include:
— Paragraph 2.C.2. Parts and Material Supplied by the Operator has changed to remove the reference to 
BMS 5-149 tape and to add reference to BMS 5-157 tape, Type 1, Class 1, Grade B, Form 1, Composition 
MPVF (Metallized Polyvinyl Fluoride) tape.
— Paragraph 2.C.2. Parts and Material Supplied by the Operator has changed to remove the reference to 
BMS 5-7 Type 1 adhesive.
— Appendix A. is changed to give the new instructions to install the BMS 8-300 insulation using BMS 5-157 
tape.
— Airplane RD233 is moved from Group 2 to Group 3.
— Duct assembly part number 65B41764-1026 has been changed to 654B41764-2026.  The 65B41764-2026 
is the same as the 65B41764-1026, except that it is wrapped with BMS 5-157 tape.  
Paragraph 1.A., Effectivity, shows changes of airplane operators.  Each operator should examine the Effectivity 
paragraph for changes.
Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location 
of important changes.
Pages with no vertical lines have no important changes.

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BOEING SERVICE BULLETIN 747-21A2422
 
REVISION HISTORY
Original Issue: August 21, 2003
Revision 1: January 20, 2005
Revision 2: November 16, 2006

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Commercial
Airplane
Group 747
Service Bulletin
Number: 747-21A2422 Summary
Date: August 21, 2003
Revision 2: November 16, 2006
ATA System: 2122
SUBJECT: AIR CONDITIONING - Distribution - Duct Insulation, BMS 8-39 Foam, Replacement
CONCURRENT REQUIREMENTS
None
BACKGROUND
Airplanes affected by this service bulletin have a single duct assembly installed that does not meet the 
flammability requirements of Federal Aviation Regulation, FAR 25.853, relating to the 12-second vertical burn 
requirement.  This is a result of the combination of BMS 8-39 foam insulation and BAC 5010, Type 98, adhesive.  
This combination of materials may present a potential fire hazard.
This service bulletin provides instructions to replace the existing duct with a new duct assembly.  Instructions 
are also provided to rework the duct assembly by removing the existing BMS 8-39, polyurethane foam 
insulation, and replacing it with BMS 8-300, polyimide foam insulation.
There have been no reports of this duct burning on 747 airplanes.
Boeing Service Related Problem (SRP) 747 SRP-21-0143 is related to this service bulletin.
ACTION (PRR 85901-18RS, Part B and C)
Replace or rework duct assembly, in the forward, lower, cargo bay.  Perform functional test.
EFFECTIVITY
Refer to Paragraph 1.A.1. Airplanes, for the list of the affected airplanes.
COMPLIANCE
The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service 
bulletin.  The Airworthiness Directive will make the compliance tasks and times given in this service bulletin 
mandatory.
INDUSTRY SUPPORT INFORMATION
Upon request, one replacement duct for each affected airplanes will be provided at no-charge.  Man-hour 
reimbursement will be provided for airplanes in warranty as of April 20, 2001.  Please refer to Paragraph 2.B., 
Industry Support Information.

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MANPOWER
MATERIAL INFORMATION
Boeing Supplied Parts
Operator Supplied Materials
Refer to Paragraph 2.A., Material - Price and Availability.
Total Task-Hours Elapsed Time (Hours)
3.75 2.25
REWORK OR REPLACE
DUCT ASSEMBLY
FORWARD CARGO DOOR
V62344

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Commercial
Airplane
Group 747
Service Bulletin
Number: 747-21A2422
Date: August 21, 2003
Revision 2: November 16, 2006
ATA System: 2122
SUBJECT: AIR CONDITIONING - Distribution - Duct Insulation, BMS 8-39 Foam, Replacement
1. PLANNING INFORMATION
A. Effectivity
1. Airplanes
Refer to Service Bulletin Index Document D6-30300 Part 3 for Airplane Variable Number, Line 
Number, and Serial Number data.
This service bulletin is for the airplanes shown below.  An equivalent change is on subsequent 
production airplanes.  Refer to PRR 85901-18RS (Part B and C) for data about this change.
Airplane models:
747-100 747-100B 747-200B 747-200C
747-200F 747-300 747-400F 747SP
747SR
IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER
AAR A/C ENG. SALES & LEASING  (AFD)
2 RB681–RB682
AERO CONTROLS  (AEO)
2 RA722–RA723
GROUP CONFIGURATION DESCRIPTION
1 - Duct Assembly 65B41764-2 installed in 
production.
2 - Duct Assembly 65B41764-5 installed in 
production.
3 - Duct Assembly 65B41764-6 installed in 
production.
4 - Duct Assembly 65B41764-6 installed in 
production.

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BOEING SERVICE BULLETIN 747-21A2422
 
AEROLINEAS ARGENTINAS  (ARG)
2 RD122–RD127
AFRICA UNITED HOLDING CO.  (UHD)
2R B 0 1 0
AFX  (AXL)
2 RD201
3 RR221
AGES AIRCRAFT SALES & LEASING  (AGJ)
2R B 0 0 4
AIR ATLANTA ICELANDIC  (AID)
2 RD141 RD414 RD647–RD648 RD771
RS211 RS222 RS233 RS235
RS237
3 RR332
AIR CANADA  (ACN)
2 RA749–RA750 RD531
AIR CHINA  (BEJ)
2 RD781
AIR FRANCE  (AFA)
2 RD657–RD658 RD721–RD722
3 RR306
AIR GULF FALCON  (GFG)
2R A 5 3 5 R A 5 3 7
AIR INDIA  (AIN)
2R A 7 2 9 R A 7 3 1
AIR PLUS COMET  (PLD)
2 RD053
AIR PULLMANTUR  (PUL)
2 RD655
AIR UNIVERSAL  (UVL)
2 RD649
ALBARAKA  (AAB)
1R B 1 0 2
ALL NIPPON AIRWAYS  (ANA)
2 RB691–RB693 RB695
AMERICAN AIRLINES  (AAL)
2R A 2 6 6

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ARKIA ISRAELI AIRLINES  (ARK)
1 RA253
ASIANA AIRLINES  (AAR)
4 RM861 RR746–RR748
ATLAS AIR  (TLS)
2 RB684 RD361–RD366 RD411 RD641–RD642
RD646 RD691–RD692 RD752–RD753
3 RJ333 RR301 RR303
4 RM891–RM899 RM901–RM903
AVIATION EXPOSURE MANAGEMENT  (EXU)
2 RD131–RD132 RD143
BAHRAIN ROYAL FLIGHT  (BHR)
3 RG009
BANC OF AMERICA LEASING  (SBC)
1 RA106
2 RD001–RD002
BOEING  (TBC)
3 RR222–RR223
BOEING AIRCRAFT HOLDING CO.  (BHC)
2 RD181 RD451–RD454
BOEING CAPITAL CORPORATION  (ZMF)
2 RB687 RD072
3 RJ132 RR201
BOEING WICHITA MOD CENTER  (WMC)
2 RD455
C.A.L. CARGO AIR LINES  (CRG)
3 RJ331–RJ332
C.I.T. LEASING CORPORATION  (TCI)
2 RB011 RD047
CARGAIR  (CGL)
2 RD203
CARGOLUX AIRLINES  (CLX)
4 RM881–RM885 RR701 RR721–RR724
CATHAY PACIFIC AIRWAYS  (CAT)
2 RD358 RD581–RD583
3 RR531
4 RM856 RR951–RR952

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CHINA AIRLINES  (CHI)
4 RL411–RL413
DUBAI AIR WING  (DAW)
2 RD622 RG191
EL AL ISRAEL AIRLINES  (ELA)
2 RD442
3 RJ152 RR225–RR226
EUROPEAN AVIATION AIR CHARTER  (EUL)
2 RD135–RD138
EVA AIR  (EVA)
4 RL401
EVERGREEN INTERNATIONAL A/L  (EVR)
2 RB604 RB607 RD004 RD041–RD043
3 RA028 RA631 RA633 RJ131
RJ133
EXPORT RESTRICTED AIRPLANES  (YWV)
1 RA101–RA103 RA112 RA161–RA162
2 RA163 RD513 RG171
3 RR001–RR004
4 RM852 RR855
GA TELESIS  (GTG)
2 RG163
GE  (GEC)
1R A 0 1 6
GE CAPITAL CORPORATION  (GEF)
1 RA007 RA013 RA027
GLOBAL AIR LEASING  (GAO)
2 RG164
GLOBAL PEACE INITIATIVE  (GPI)
2 RG174
GRACE CATHEDRAL INC.  (GCI)
2 RG193
GUGGENHEIM AVIATION PARTNERS  (GPR)
2R B 6 9 7
IBERIA AIRLINES  (IBE)
2 RD431–RD435
INTERNATIONAL AIR LEASES  (IAL)
2R B 0 0 6

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IRAN AIR  (IRN)
2 RB711 RD681–RD682 RG101–RG104
IRAQI AIRWAYS  (IRQ)
2 RG095 RG172
3 RJ301–RJ303
JAL INTERNATIONAL  (JAL)
2 RA546 RA548 RD055 RD222–RD226
RS251–RS253
3 RR264–RR265 RR361–RR362
JET AERO HOLDINGS  (JHD)
2 RG122
JUMBO JET LEASING  (JJL)
2 RA526 RA532–RA534 RA539
KABO AIR  (KAB)
1 RA305
2 RA316 RA560 RB008 RD121
KALITTA AIR  (KAC)
2 RA401–RA402 RA524 RA545 RA547
RA635 RA913 RD054 RD082–RD083
RD221 RD571 RD621 RD623
3 RB605 RR261–RR262 RR501 RR521
KLM - ROYAL DUTCH AIRLINES  (KLM)
2 RD382 RD607
KOREAN AIR  (KAL)
4 RM871–RM873 RR861–RR862
KUWAIT AIRWAYS  (KUW)
2 RD202 RD204
L-3 COMMUNICATIONS  (LCS)
2 RD352
LOGISTIC AIR, INC.  (LGA)
1 RA015
2 RA217 RB722–RB723
MARTINAIR HOLLAND  (MTH)
2 RD601
MK AIRLINES  (MKA)
2 RD441 RD561
3 RR022–RR023 RR224 RR336 RR421
NASA  (NAS)
2 RA908 RB601

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NEA HOLDINGS, INC.  (NEA)
2 RB001 RD045–RD046
NIPPON CARGO AIRLINES  (NCA)
3 RB696 RD233 RD461 RR551
NORTHWEST AIRLINES  (NWA)
2 RA370–RA373 RD056–RD057 RD241–RD243 RD251–RD259
RS701–RS702
3 RR005 RR341–RR345 RR503
OCEAN AIRLINES  (OCE)
3 RR202–RR203
OMAN ROYAL FLIGHT  (RFO)
2 RG161
OMEGA AIR HOLDINGS  (OMC)
2 RB694 RD142 RD144 RD412
ORIENT THAI AIRLINES  (OTH)
2 RA528 RA540 RA543–RA544 RD516
RS712
PAKISTAN INT'L AIRLINES  (PIA)
2 RD104 RD701–RD702
PHUKET AIRLINES  (PHK)
2 RD381 RD421–RD424 RD605 RS711
POLAR AIR CARGO  (PAO)
2R A 9 1 0
3 RR504
4 RL651
PRATT & WHITNEY ENGINE SERVICE  (PWE)
2 RG213
QANTAS  (QAN)
2 RS271–RS272
ROYAL AIR MAROC  (RAM)
2 RD671
SATAIR  (SAI)
2 RD383 RD606
SAUDI ARABIAN AIRLINES  (SVA)
2 RB741–RB746 RB748
3 RH121

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SAUDI ROYAL FLIGHT  (SRF)
2 RH101 RS699
3 RH122
SINGAPORE AIRLINES  (SIA)
4 RM851 RM853 RR851–RR854 RR856
SKY EXPRESS S.A.  (SXS)
2 RD592
SOUTH AFRICAN AIRWAYS  (SAA)
2 RG123 RG125 RS212 RS232
RS236
SOUTHERN AIR  (SOF)
2 RD182 RD272 RD602 RD604
RD643
3 RR302 RR304–RR305
SUO1  (UO1)
2 RB013–RB016
SYRIANAIR  (SYR)
2 RG141–RG142
TESIS AVIATION ENTERPRISE  (TEV)
2 RA784
TRADEWINDS AIRLINES  (TWN)
2 RA726 RD052 RD426
TRANSAERO AIRLINES  (TRX)
2 RD356 RD471–RD475
TRANSATLANTIC INTL AIRLINES  (TIB)
2 RG173
UPS  (UPS)
2 RA033 RA912 RA915–RA916 RD051
RD058–RD059 RD593
3 RA026 RA029 RA902
US AIR FORCE  (USF)
4R M 9 1 1
USRA  (USP)
3 RG091
VIRGIN ATLANTIC AIRWAYS  (VAA)
2 RD357

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BOEING SERVICE BULLETIN 747-21A2422
 
VOLGA-DNEPR AIRLINES  (VDA)
2 RD751
3 RR561
WHIRLPOOL FINANCIAL CORP.  (ZZW)
2R B 0 0 5
WINGS WORLD WIDE  (WWW)
2 RG221–RG222
WORLDWIDE AIRCRAFT HOLDING CO.  (WAH)
3 RG008
YEMENIA  (YEM)
2 RG162
IDENTIFICATION BY VARIABLE NUMBER
Variable  Group
RA001–RA025 1
RA026 3
RA027 1
RA028–RA029 3
RA030–RA034 2
RA101–RA114 1
RA161–RA162 1
RA163–RA164 2
RA201–RA203 1
RA216–RA217 2
RA245–RA246 2
RA251–RA255 1
RA256–RA266 2
RA301–RA305 1
RA307–RA318 2
RA351–RA360 1
RA370–RA373 2
RA401–RA418 2
RA501–RA502 1
RA521–RA523 1
RA524–RA528 2
RA532–RA548 2
RA551–RA552 1
RA559–RA561 2
RA581–RA582 1

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RA585 2
RA601–RA602 1
RA631 3
RA632 1
RA633 3
RA634–RA635 2
RA652 2
RA672–RA677 2
RA701–RA702 2
RA721–RA731 2
RA741 1
RA742–RA745 2
RA749–RA750 2
RA761 1
RA762 2
RA781–RA784 2
RA901 2
RA902 3
RA903–RA916 2
RB001–RB016 2
RB041–RB043 1
RB044 2
RB071–RB075 2
RB101–RB102 1
RB601–RB604 2
RB605 3
RB606–RB607 2
RB681–RB695 2
RB696 3
RB697 2
RB711 2
RB721–RB723 2
RB741–RB748 2
RD001–RD004 2
RD021–RD022 2
RD041–RD059 2
RD071–RD072 2
RD081–RD083 2
RD091–RD092 2
Variable  Group

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RD101–RD104 2
RD121–RD127 2
RD131–RD144 2
RD171–RD172 2
RD181–RD183 2
RD201–RD204 2
RD221–RD226 2
RD233 3
RD241–RD243 2
RD251–RD259 2
RD271–RD272 2
RD351–RD358 2
RD361–RD366 2
RD381–RD383 2
RD411–RD414 2
RD421–RD426 2
RD431–RD435 2
RD441–RD442 2
RD451–RD455 2
RD461 3
RD471–RD475 2
RD513–RD519 2
RD531–RD533 2
RD551 2
RD561 2
RD571 2
RD581–RD583 2
RD591–RD593 2
RD601–RD607 2
RD621–RD623 2
RD641–RD649 2
RD651–RD658 2
RD661 2
RD671 2
RD681–RD682 2
RD691–RD692 2
RD701–RD702 2
RD721–RD722 2
RD741–RD742 2
Variable  Group

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BOEING SERVICE BULLETIN 747-21A2422
 
 
RD751–RD753 2
RD761 2
RD771 2
RD781 2
RE001 2
RG001–RG009 3
RG091 3
RG095 2
RG101–RG104 2
RG121–RG126 2
RG141–RG142 2
RG161–RG164 2
RG171–RG174 2
RG191–RG193 2
RG211–RG213 2
RG221–RG222 2
RH101 2
RH111–RH112 2
RH121–RH122 3
RJ131–RJ133 3
RJ151–RJ152 3
RJ301–RJ303 3
RJ331–RJ333 3
RL401 4
RL411–RL413 4
RL651 4
RM851–RM853 4
RM856 4
RM861 4
RM871–RM873 4
RM881–RM885 4
RM891–RM899 4
RM901–RM903 4
RM911 4
RR001–RR005 3
RR021–RR023 3
RR031 3
RR201–RR203 3
RR221–RR226 3
Variable  Group

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2. Spares Affected
Examine your spares supply for the parts or components identified in Paragraph 2.C., Parts 
Necessary for Each Airplane.  If any parts or components are found, refer to Paragraph 2.C. for 
the recommended use.
B. Concurrent Requirements
None
RR261–RR265 3
RR301–RR306 3
RR331–RR332 3
RR336 3
RR341–RR345 3
RR361–RR362 3
RR421–RR422 3
RR501–RR504 3
RR521 3
RR531 3
RR551 3
RR561 3
RR701 4
RR721–RR724 4
RR746–RR748 4
RR851–RR856 4
RR861–RR862 4
RR951–RR952 4
RS201 2
RS211–RS212 2
RS221–RS222 2
RS231–RS237 2
RS251–RS253 2
RS271–RS272 2
RS291 2
RS699 2
RS701–RS702 2
RS711–RS712 2
Variable  Group

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BOEING SERVICE BULLETIN 747-21A2422
 
 
C. Reason
Airplanes affected by this service bulletin have a single duct assembly installed that does not meet the 
flammability requirements of Federal Aviation Regulation, FAR 25.853, relating to the 12-second 
vertical burn requirement.  This is a result of the combination of BMS 8-39 foam insulation and BAC 
5010, Type 98, adhesive.  This combination of materials may present a potential fire hazard.
This service bulletin provides instructions to replace the existing duct with a new duct assembly.  
Instructions are also provided to rework the duct assembly by removing the existing BMS 8-39, 
polyurethane foam insulation, and replacing it with BMS 8-300, polyimide foam insulation.
There have been no reports of this duct burning on 747 airplanes.
Revision 1 is sent to update the effectivity from the initial release of this service bulletin. Airplanes 
RA026 and RA029 have been removed from Group 1 and added to Group 3. These airplanes were 
originally fitted with 65B41764-6 Ducts. 
Airplanes RA028, RA631, and RA633 have been removed from Group 1 and added to Group 3. These 
airplanes were modified and fitted with 65B41764-6 ducts.
Airplanes RA902, RB605, RB696 and RD461 have been removed from Group 2 and added to Group 
3. These airplanes were originally fitted with 65B41764-6 Ducts. 
 Airplane RD233 was omitted from the initial release of this service bulletin and has now been included 
in Group 2.
Changes to this service bulletin include:
— Paragraph 2.A., Material - Price and Availability - part quantities for Groups 2, 3 and 4 airplanes 
have been revised.
— Paragraph 2.C.2., Material - Parts Supplied by the Operator - Fiberglass Tape, Style 116, per 
BMS 9-3R, was added to the table.
— Appendix B: BAC 5412 Method VII - Bonding Duct Joints - revised to include a change of 
supplier.
Revision 02 is sent to give operators approval to use BMS 5-157 tape instead of the non-compliant 
BMS 5-149 tape.  This change gives operators new instructions to apply BMS 8-300 insulation to the 
Environmental Control System (ECS) ducts with BMS 5-157 tape.  The BMS 5-157 tape must fully 
cover the BMS 8-300 insulation.  The new configuration for the ECS duct insulation meets the 
flammability requirements of 14CFR 25.856(a), Amendment 111.  Airplanes that have the intent of this 
service bulletin done after September 02, 2005, must satisfy the new requirements by fully covering 
the brown hypalon cover of the BMS 8-300 insulation with BMS 5-157 tape.
Changes to this service bulletin include:
— Paragraph 2.C.2. Parts and Material Supplied by the Operator has changed to remove the 
reference to BMS 5-149 tape and to add reference to BMS 5-157 tape, Type 1, Class 1, Grade 
B, Form 1, Composition MPVF (Metallized Polyvinyl Fluoride) tape.
— Paragraph 2.C.2. Parts and Material Supplied by the Operator has changed to remove the 
reference to BMS 5-7 Type 1 adhesive.
— Appendix A. is changed to give the new instructions to install the BMS 8-300 insulation using 
BMS 5-157 tape.
— Airplane RD233 is moved from Group 2 to Group 3.

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— Duct assembly part number 65B41764-1026 has been changed to 654B41764-2026.  The 
65B41764-2026 is the same as the 65B41764-1026, except that it is wrapped with BMS 5-157 
tape.  
Paragraph 1.A., Effectivity, shows changes of airplane operators.  Each operator should examine the 
Effectivity paragraph for changes.
Boeing Service Related Problem (SRP) 747 SRP-21-0143 is related to this service bulletin.
D. Description
Replace or rework duct assembly, in the forward, lower, cargo bay.  Perform functional test.
Revision 2 - More work is necessary on airplanes changed as shown in the initial release or Revision 
01 of this service bulletin, if accomplished after September 02, 2005.  If the intent of this Revision 02 
was accomplished after September 02, 2005, then no more work is required.
The airplane effectivity is divided into four groups. The difference between the airplane groups is 
limited to the part number installed on the airplane and the specification requirements for reinstalling 
the new duct assembly.
The changes in this service bulletin will not change the Central Maintenance Computer System 
(CMCS).
E. Compliance
The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to 
this service bulletin.  The Airworthiness Directive will make the compliance tasks and times given in 
this service bulletin mandatory.
F. Approval
This service bulletin was examined by the Federal Aviation Administration (FAA). The changes 
specified in this service bulletin comply with the applicable regulations and are FAA approved, as well 
as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/
JAA approved airplanes listed in the service bulletin effectivity.  This service bulletin and its approval 
were based on the airplane in its original Boeing delivery configuration or as modified by other 
approved Boeing changes.
If an airplane has a non-Boeing modification or repair that affects a component or system also affected 
by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency 
approval before incorporating this service bulletin.
G. Manpower
The table below shows an estimate of the task-hours necessary to do this change for each airplane.  
This estimate is for direct labor only, done by an experienced crew.  Adjust the estimate with operator 
man-hour data if necessary.  The estimate does not include lost time.  These are some examples of 
lost time:
— Time to adjust to the workplace
— Time to schedule the work
— Time to examine the work
— Time to cure the materials

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— Time to make the parts
— Time to find the tools.
H. Weight and Balance Changes
None
I. Electrical Load Data
Not applicable
J. References
1. Existing Data:
a. Engineering Change Memo PRR 85901-18RS, Part B and C
b. 747 Aircraft Maintenance Manual (AMM) 25-52-01
c. 747 Illustrated Parts Catalog (IPC) 21-22-06
d. 747-100/200/300 Aircraft Maintenance Manual (AMM) 21-23-01
e. 747-400 Aircraft Maintenance Manual (AMM) 21-23-02
f. Service Related Problem (SRP) 747 SRP-21-0143
g. Boeing Standard Overhaul Practices Manual (SOPM) 20-30-03, 20-50-12, 20-60-01
2. Data supplied with this Service Bulletin:
None
3. Installation Drawings Used in the Preparation of this Service Bulletin:
These drawings were used to prepare this service bulletin.  These drawings are not necessary 
to make the specified changes, and are not supplied with this service bulletin.  These drawings 
may not be applicable to all airplane configurations or operators.
Task Number of Persons Task-Hours Elapsed Time (Hours)
Open Access 2 1.5 0.75
Change 1 0.75 0.75
Close Access 2 1.5 0.75
TOTAL FOR EACH  AIRPLANE 3.75 2.25
Drawing Number Title
65B40176 Duct Installation - Flight Deck Air Condi-
tioning, Section 42
217U1003 Duct Installation - Forward E/E Cooling
Supply

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BOEING SERVICE BULLETIN 747-21A2422
 
4. Process Data:
Boeing Process Specifications referred to on the drawings are not given in this service bulletin 
since these procedures are frequently used as standard shop practices.
The procedures shown that are not frequently used and are shown in Appendix B and C.
K. Publications Affected
L. Interchangeability and Intermixability of Parts
Refer to Paragraph 2.C., Parts Necessary For Each Airplane, for interchangeability and intermixability 
information.
Publication Chapter-Section
747 Illustrated Parts Catalog 747 IPC 21-22-06

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BOEING SERVICE BULLETIN 747-21A2422
 
 
2. MATERIAL INFORMATION
A. Material - Price and Availability
Replacement ducts for all affected airplanes  will be provided at no-charge upon request.  Boeing can 
supply the parts shown in Paragraph 2.C., Parts Necessary For Each Airplane as shown below.  If 
there is a limit in the quantity (QTY) of parts, a supply sequence is given by Spares.
The parts are subject to the terms and conditions of the Boeing standard purchase order 
acknowledgment.
Reference this service bulletin and submit your purchase order by one of the methods that follow:  
1. Order on-line via ATA Spec 2000 or Boeing Part Page
2. Fax to (206) 662-7145
3. Spares Customer Support - MC 36-65
Boeing Spares Department
P.O. Box 3707
Seattle, Washington   98124-2207  USA
B. Industry Support Information
Upon request, one replacement duct for each affected airplane will be provided at no-charge, 
regardless of warranty status.  Task-hour reimbursement will be provided for airplanes in warranty as 
of April 20, 2001.  Send a purchase order for the part to Boeing Spares and a claim for labor 
reimbursement to Boeing Warranty.  Please refer to this service bulletin number and reference the 
airplane variable number in your purchase orders and labor reimbursement claim.
Part Number Name Airplane Group Date QTY
65B41764-1002 Duct Assembly (Group 1 Airplanes) April 16, 2002 20
65B41764-1005 Duct Assembly (Group 2 Airplanes) May 14, 2002 90
65B41764-2026 Duct Assembly (Group 3 and Group 4 Airplanes) May 28, 2002 79

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BOEING SERVICE BULLETIN 747-21A2422
 
C. Parts Necessary For Each Airplane
1. Kits/Parts:
The operator has the option to do this change with one of the following two methods.
a. Remove and discard the affected duct and replace with a new duct provided by Boeing.
b. Remove, rework, partmark, then install the reworked duct.
To get the parts shown below, refer to Paragraph 2.A., Material - Price and Availability.  One new 
duct assembly or one reworked duct assembly is required for each airplane.
QTY Part Number Name Note
1 65B41764-1002 Duct Assembly (Group 1 Airplanes) (a)
1 65B41764-1005 Duct Assembly (Group 2 Airplanes) (a)
1 65B41764-2026 Duct Assembly (Group 3 and Group 4 Airplanes)
(a) If this duct is installed, it must be wrapped with BMS 5-157 tape as given in Appendix A.

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2. Parts and Materials Supplied by the Operator:
NOTE: For the re-attachment of a new or reworked duct assembly there are several options
which are outlined in your applicable figure.  For these additional material requirements
see the following specifications: SOPM 20-50-12 Type 44; SOPM 20-50-12, Type 117;
this service bulletin, Appendix B (BAC 5412 Method VII), and Appendix C (BAC 5412
Method VIII).
NOTE: The materials listed below, except for the tie strap, are for reworking the duct assembly
by applying the new insulation and wrapping the insulation with BMS 5-157 tape.
3. Parts Modified and Reidentified:
The parts shown below are changed as shown in this service bulletin.  The quantity (QTY) is the 
number of parts changed on each airplane.
QTY Part Number {Specification} Name
1 sheet BMS 8-300 Type 2, Grade 0.6  or Grade 5, with
thickness of 0.375 inches, 4 feet X 8 feet sheet
Polyimide Foam Insulation (a) (b)
(e)
As required BMS 5-157, Type 1, Class 1, Grade B, Form 1,
Composition MPVF (Metallized polyvinyl Fluoride)
Widths: 2 inch, 3 inch and 12 inch
Tape (c) (e)
3 ounces BMS 5-7, Type 2 Adhesive (a) (e)
6 Feet Style 116 Per BMS 9-3R, Type C, Class 7, slit and
sealed, 3 inches nominal width
Fiberglass Tape (a) (e)
1B A C S 3 8 K 6 T i e  S t r a p
(a) These materials are not required if the existing duct is being replaced with a new duct assembly.
(b) Vendor Contact Information:
Jehier SA
Route DE Saint-Lezin
F-49120
Chemille, France
                or Boyd Corporation
6236 N.E. 87th Avenue
Portland, OR 97220, USA
(c) Tape BMS 5-157, Type 1, Class 1, Grade B, Form 1, Composition MPVF (Metallized Polyvinyl Flu-
oride), replaces tape BMS 5-149, Type 11, Class 1 or 2, Grade C, Form 1.
(d) Vendor Contact Information:
E&H Laminating and Slitting Company
138 Grand Street
Paterson, NJ 07501, USA
Telephone (973) 345-3224
(e) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier
data.
Existing Part 
Number QTY Name New Part Number Notes
65B41764-2 1 Duct Assembly 65B41764-1002 (a) (b)
65B41764-5 1 Duct Assembly 65B41764-1005 (a) (b)

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BOEING SERVICE BULLETIN 747-21A2422
 
4. Parts Removed and Not Replaced:
None.
D. Parts Necessary to Change Spares
See Paragraph 2. C. 2. Parts and Materials Supplied by the Operator, for the material required to 
rework ducts in the operators spares supply.
E. Special Tooling - Price and Availability
None
F. Special Tooling Necessary to do this Service Bulletin
No special tools or equipment are necessary to do the change in this service bulletin.  But, 
maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be 
necessary.  Examine operator tool supply to make sure all necessary tools are available.
65B41764-6 1 Duct Assembly 65B41764-2026 (a) (b)
(a)  Make the change given in this service bulletin.
(b) This is the part number after the change given in this service bulletin.
Existing Part 
Number QTY Name New Part Number Notes

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BOEING SERVICE BULLETIN 747-21A2422
 
 
3. ACCOMPLISHMENT INSTRUCTIONS
A. GENERAL INFORMATION
CAUTION: KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL
PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS.  UNWANTED
MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES
CAN CAUSE DAMAGE TO THE BUNDLES.  DAMAGED WIRE BUNDLES CAN CAUSE
SPARKS OR OTHER ELECTRICAL DAMAGE.
NOTE:
1. Reference 747-100/200/300 AMM 21-23-01and 747-400 AMM 21-23-02, for information 
to repair damaged ducts.
2. If the duct assembly is reworked, the instructions are given in Appendix A.
3. 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
— Torque limits to tighten nuts and bolts are given in 747 Structural Repair Manual, 
Chapter 51.
4. Obey all of the warnings and cautions given in the specified manual sections. 
B. WORK INSTRUCTIONS
1. Get access to the affected duct assembly as shown in Figure 1.
2. Remove, then rework as given in Appendix A or replace the affected duct assembly as follows:
— Group 1 airplanes do Figure 2.
— Group 2 airplanes do Figure 3.
— Group 3 airplanes do Figure 4.
— Group 4 airplanes do Figure 5.
3. Do the following functional test to determine that the duct assembly has been installed correctly 
and does not leak.
a. Pressurize the affected duct assembly by running at least two of the air conditioning packs, 
(or use a suitable equivalent ground cart).  Apply power to the recirculation fans, (If the 
airplane is in the GROUND MODE, only the upper recirculation fans will operate).
b. For the replacement duct, verify by sound and feel that there are no concentrated leaks at 
the duct joints.  Small leaks are permitted.  Large or concentrated leaks must be repaired.
— (A concentrated or large leak is defined as a jet or stream of air that can be felt on the 
palm of the hand, three to four inches from the surface of the duct).
4. Install the forward cargo compartment panels removed in Figure 1.  Reference 747 AMM 
25-52-01.
5. Put the airplane back to a serviceable condition.

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FIGURE 1: DUCT ACCESS, ALL AIRPLANE GROUPS
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BOEING SERVICE BULLETIN 747-21A2422
 
FIGURE  1:   DUCT ACCESS, ALL AIRPLANE GROUPS
4
FORWARD CARGO DOOR
3
2
1
V62348
LOOKING AFT
FORWARD CARGO COMPARTMENT
(SHEET 1 OF 2)

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FIGURE 1: DUCT ACCESS, ALL AIRPLANE GROUPS
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BOEING SERVICE BULLETIN 747-21A2422
 
 
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
The QTY numbers shown below are the numbers of parts necessary for one airplane.
STEP TASK NAME REFERENCES QTY NOTES
1 Remove Sidewall Panel 747 AMM 25-52-01 1 -
2 Remove Ceiling Panel - 1 -
3 Remove Bulkhead Panel - 1 -
4 Identify Duct Assembly 65B41764-2 1 Group 1 Airplanes
65B41764-5 1 Group 2 Airplanes
65B41764-6 1 Group 3 and Group 4 Airplanes
(SHEET 2 OF 2)

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FIGURE 2: DUCT ASSEMBLY REWORK, GROUP 1 AIRPLANES
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BOEING SERVICE BULLETIN 747-21A2422
 
FIGURE  2:   DUCT ASSEMBLY REWORK, GROUP 1 AIRPLANES
6
ASEE
TYPICAL VIEW
A
4
5
321
1000
STA
FORWARD CARGO DOOR
FWD
UP
V62351
(SHEET 1 OF 2)

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FIGURE 2: DUCT ASSEMBLY REWORK, GROUP 1 AIRPLANES
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BOEING SERVICE BULLETIN 747-21A2422
 
 
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
The QTY numbers shown below are the numbers of parts necessary for one airplane.
CAUTION: THE FORWARD DUCT CONNECTION IS JOINED WITH ADHESIVE. USE CARE WHEN
SEPARATING THIS CONNECTION AS NOT TO DAMAGE EITHER DUCT ASSEMBLY.
STEP TASK NAME PART NUMBER QTY NOTES
1 Remove/
Discard or
Rework
Duct Assembly 65B41764-2 1 Reference Appendix A for re-
work instructions.
2 Mark Part Number 65B41764-1002 1 Part marking required only if you
are reworking the existing duct
assembly.
3I n s t a l l
(New) or
Reworked
Duct Assembly 65B41764-1002 1 -
4 Install Strap BACS38K6 1 -
5 Attach Duct Joint - - Reference procedure in Appen-
dix C, (BAC 5412, Method VIII).
6 Attach Duct Joint - - Reference BSOPM 20-50-12,
Type 44 or Type 117.
(SHEET 2 OF 2)

### Page 34

FIGURE 3: DUCT ASSEMBLY REWORK, GROUP 2 AIRPLANES
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 34 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
FIGURE  3:   DUCT ASSEMBLY REWORK, GROUP 2 AIRPLANES
FORWARD CARGO DOOR
STA
1000
1 2 3
5
4
A
TYPICAL VIEW
ASEE
6
FWD
UP
V62402
(SHEET 1 OF 2)

### Page 35

FIGURE 3: DUCT ASSEMBLY REWORK, GROUP 2 AIRPLANES
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 35 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
 
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
The QTY numbers shown below are the numbers of parts necessary for one airplane.
CAUTION: THE FORWARD DUCT CONNECTION IS JOINED WITH ADHESIVE. USE CARE WHEN
SEPARATING THIS CONNECTION AS NOT TO DAMAGE EITHER DUCT ASSEMBLY.
STEP TASK NAME PART NUMBER QTY NOTES
1 Remove/
Discard or
Rework
Duct Assembly 65B41764-5 1 Reference Appendix A for re-
work instructions.
2 Mark Part Number 65B41764-1005 1 Part marking required only if you
are reworking the existing duct
assembly.
3I n s t a l l ;
(New) or
Reworked
Duct Assembly 65B41764-1005 1 -
4 Install Strap BACS38K6 1 -
5 Attach Duct Joint - - Reference procedure in Appen-
dix C, (BAC 5412, Method VIII).
6 Attach Duct Joint - - Reference BSOPM 20-50-12,
Type 44 or Type 117.
(SHEET 2 OF 2)

### Page 36

FIGURE 4: DUCT ASSEMBLY REWORK, GROUP 3 AIRPLANES
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 36 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
FIGURE  4:   DUCT ASSEMBLY REWORK, GROUP 3 AIRPLANES
FORWARD CARGO DOOR
STA
1000
1 2 3
5
4
A
TYPICAL VIEW
ASEE
6
FWD
UP
V62403
(SHEET 1 OF 2)

### Page 37

FIGURE 4: DUCT ASSEMBLY REWORK, GROUP 3 AIRPLANES
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 37 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
 
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
The QTY numbers shown below are the numbers of parts necessary for one airplane.
CAUTION: THE FORWARD DUCT CONNECTION IS JOINED WITH ADHESIVE. USE CARE WHEN
SEPARATING THIS CONNECTION AS NOT TO DAMAGE EITHER DUCT ASSEMBLY.
STEP TASK NAME PART NUMBER QTY NOTES
1 Remove/
Discard or
Rework
Duct Assembly 65B41764-6 1 Reference Appendix A for re-
work instructions.
2 Mark Part Number 65B41764-2026 1 Part marking required only if you
are reworking the existing duct
assembly.
3I n s t a l l
(New) or
Reworked
Duct Assembly 65B41764-2026 1 -
4 Install Strap BACS38K6 1 -
5 Attach Duct Joint - - Reference procedure in Appen-
dix C, (BAC 5412, Method VIII).
6 Attach Duct Joint - - Reference BSOPM 20-50-12,
Type 44 or Type 117.
(SHEET 2 OF 2)

### Page 38

FIGURE 5: DUCT ASSEMBLY REWORK, GROUP 4 AIRPLANES
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 38 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
FIGURE  5:   DUCT ASSEMBLY REWORK, GROUP 4 AIRPLANES
FORWARD CARGO DOOR
STA
1000
1 2 3
5
4
A
TYPICAL VIEW
ASEE
6
FWD
UP
V62404
(SHEET 1 OF 2)

### Page 39

FIGURE 5: DUCT ASSEMBLY REWORK, GROUP 4 AIRPLANES
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 39 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
 
The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
The QTY numbers shown below are the numbers of parts necessary for one airplane.
CAUTION: THE FORWARD DUCT CONNECTION IS JOINED WITH ADHESIVE. USE CARE WHEN
SEPARATING THIS CONNECTION AS NOT TO DAMAGE EITHER DUCT ASSEMBLY.
STEP TASK NAME PART NUMBER QTY NOTES
1 Remove/
Discard or
Rework
Duct Assembly 65B41764-6 1 Reference Appendix A for re-
work instructions.
2 Mark Part Number 65B41764-2026 1 Part marking required only if you
are reworking the existing duct
assembly.
3I n s t a l l
(New) or
Reworked
Duct Assembly 65B41764-2026 1 -
4 Install Strap BACS38K6 1 -
5 Attach Duct Joint - - Reference procedure in Appen-
dix B, (BAC 5412, Method VII).
Also can use optional procedure
BSOPM 20-50-12, Type 117.
6 Attach Duct Joint - - Reference BSOPM 20-50-12,
Type 70, 79, or 117.
(SHEET 2 OF 2)

### Page 40

APPENDIX A: PROCESS DATA - APPLICATION OF BMS 8-300 BY TAPING WITH BMS 5-157 TAPE
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 40 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
APPENDIX  A:   PROCESS DATA - APPLICATION OF BMS 8-300 BY TAPING WITH BMS 5-157 TAPE
NOTE: Reference 747-100/200/300 AMM 21-23-01 and 747-400 AMM 21-23-02, for information to repair
damaged ducts.
1. Remove existing insulation from duct assembly.  Apply new insulation using the following information.  
NOTE: When insulation is removed, some residual adhesive and foam insulation may remain attached to
the duct assembly. Small amounts are permissible.  If there is an excessive amount of insulation
still attached to the duct, it can be removed with a scotch-brite pad.  Surface cleaning of the duct
is not required.
2. Insulation material shall be in accordance with BMS 8-300, Type II, Grade 0.6 or Grade 5, 0.375 inch 
thickness.
3. Insulation blanket tape shall be in accordance with BMS 5-157, Type 1, Class 1, Grade B, Form 1, 
Composition MPVF (Metallized Polyvinyl Fluoride), 2 inch, 3 inch, or 12 inch widths.
NOTE: Tape BMS 5-157, Type 1, Class 1, Grade B, Form 1, Composition MPVF (Metallized Polyvinyl
Fluoride), replaces BMS 5-149, Type 11, Class 1 or 2, Grade C, Form 1.  Do not use BMS 5-149
tape with BMS 8-300 insulation.
4. Install the insulation with the foam side against the duct surface.  Where, due to size and shape of duct, 
more than one piece of insulation is required, individual pieces may be used.  Use BMS 5-157 tape to 
secure the insulation in position.
5. If bonding is necessary to tack bond the insulation to the duct to maintain the position prior to tape 
application, refer to Boeing Standard Overhaul Practices Manual 20-50-12, Type 58, BMS 5-7, Type 2.  A 
single coat of adhesive may be used in either one or both surfaces to be bonded.  The following 
requirements shall also apply:
A. Lengthwise along duct - Adhesive bond lines of up to 2 inches wide are allowed, but no two bondlines 
may be closer than 12 inches centerline to centerline.
B. Bonding circumferentially - Adhesive bond lines of up to 2 inches wide around the duct, but no two 
bondlines may be closer than 12 inches centerline to centerline.
C. Spot tack bonding - 2 inch diameter (approximately) spots of adhesive may be used, but no two 
adhesives spots may be closer than 12 linear inches, center to center.
D. Edge bonding - Adhesive bondline may be up to 2 inches wide around the periphery of the insulation, 
or at seam or slit locations, and is acceptable on ducts or insulation of all sizes as necessary.
E. No overspray of adhesive is allowed outside the area to be covered by insulation.  Minimize use of 
adhesives for bonding.  Mask as required.
6. Use the tape in short strips (4 inches long or smaller), doubled over or double sided, at the discretion of the 
operator, to assist in holding the insulation in place.
7. The insulation shall be applied to within 3 inches of each end of the duct outlet or flange and to within 1 
inch of any spud or appendage as shown in the duct rework illustrations.

### Page 41

APPENDIX A: PROCESS DATA - APPLICATION OF BMS 8-300 BY TAPING WITH BMS 5-157 TAPE
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 41 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
 
8. Apply the tape such that no edge of the insulation blanket is exposed.  In addition, apply tape to within 2 
inches (1.25 inch minimum) of each end of the duct outlet or flange, and in contact with any spud or 
appendage as shown in the duct rework illustrations.
9. Butt edges of insulation together within a gap of 0.10 inch to an overlap of 0.25 inch, and apply tape along 
seam to secure blanket.
10. Apply an additional circumferential or lengthwise wrap of BMS 5-157, Type 1, Class 1, Grade B, Form 1, 
Composition MPVF, tape that covers 100% of the brown hypalon surface of the BMS 8-300 insulation.
A. The BMS 5-157 tape can be installed in a spiral wrap or along the duct.  Tape applied in a spiral wrap 
around the duct bends and on the flat areas is recommended.
B. Wider tape can be cut into thinner strips or different shapes to help fully cover the BMS 8-300 
insulation.
C. Make sure that there is a minimum of 1/8 inch overlap of the BMS 5-157 tape.
D. Avoid compression of the BMS 8-300 insulation.
E. Wrinkles in the tape are permitted if pinched together and contain no voids.
F. Tape can be applied to the insulation blanket before the insulation blanket is installed on the duct 
assembly.
G. Cut tape as needed to fit around air outlets, branches and insulation vent holes. 
11. All tolerances to be plus or minus 0.25 inch unless otherwise specified.
12. Partmark location should be within 6 inches of either end of the duct assembly, but not closer than 1 inch 
from the end of the duct, to prevent the part number from being covered by the sleeve during installation.

### Page 42

APPENDIX A: PROCESS DATA - APPLICATION OF BMS 8-300 BY TAPING WITH BMS 5-157 TAPE
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 42 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
INSULATION
BLANKET
BEAD OR FLANGE
F
DD
C
TAPE
C
3.00 TYPICAL
AT DUCT END
B
B
INSULATION
BLANKET
SEAMA
A
EDGE OF
INSULATION
BLANKET
EDGE OF
INSULATION
BLANKET
TAPE
EDGE OF
2.00 TYPICAL
EDGE OF TAPE
DUCT
TAPE
BLANKET
INSULATION
SEAM
BLANKET
INSULATION
SEAM
TAPE
INSULATION
BLANKET
DUCT
INSULATION
BLANKET
TAPE
AIR OUTLET
TYP
AIR OUTLET
TYP
TAPE
1.00 FROM
EDGE OF INSULATION
BLANKET
DUCT
TYP
AIR OUTLET
1.00 FROM
TAPE
AIR
OUTLET
TAPE
BLANKET
INSULATION
INSULATION END
OVERLAP AT
TAPE
A-A B-B
EXISTING
DUCT
EDGE OF
TAPE
0.125 MIN
TAPE
OVERLAP
BMS 5-157
TAPE BMS 8-300 INSULATION
EDGE OF TAPE
AT DUCT END
(1.25 MINIMUM)
V62353

### Page 43

APPENDIX A: PROCESS DATA - APPLICATION OF BMS 8-300 BY TAPING WITH BMS 5-157 TAPE
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 43 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
 
EE TYPAIR OUTLET
INSULATION
BLANKET
EDGE OF
3.00
TAPE
4.00
TAPE
EDGE OF
DUCT
TYPICAL INSULATED DUCT ASSEMBLY
AS REQUIRED
AREA TO CLEAR OUTLET
TRIM TAPE IN OVERLAP
LENGTH AS
REQUIRED
BLANKET
INSULATION (2 LOCATIONS)
2.00
INSULATION
TAPE
AIR
OUTLET
INSULATION
BLANKET
INSULATION
SEAM
BLANKET
EDGE OF
TAPE
1.00 FROM
DUCT
BLANKET
WITH OUTLET AT END
TYPICAL ARRANGEMENT AT END OF DUCT
C-C
D-D
2.00 TYPICAL
(1.25 MINIMUM)
V62354

### Page 44

APPENDIX A: PROCESS DATA - APPLICATION OF BMS 8-300 BY TAPING WITH BMS 5-157 TAPE
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 44 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
ROTATED 35 DEGREES CW
TYPICAL ARRANGEMENT FOR ALL
90 DEGREE AIR OUTLETS EXCEPT AS NOTED
INSULATION BLANKET
INSULATION BLANKET
AIR OUTLET
AIR OUTLET
TAPE
TAPE
2.00
4.00
(2 LOCATIONS)
4.00
(2 LOCATIONS)
4.00
(2 LOCATIONS)
(2 LOCATIONS)
7.00
TYPICAL ARRANGEMENT FOR ALL
ANGLED AIR OUTLETS EXCEPT AS NOTED
(4 LOCATIONS)
F-F
E-E
N29354

### Page 45

APPENDIX B: BAC 5412 METHOD VII - BONDING DUCT JOINTS
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 45 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
 
APPENDIX  B:   BAC 5412 METHOD VII - BONDING DUCT JOINTS
1. Coat the three inch wide fiberglass tape, Style 116 on one side with BAC 5010, Type 98 adhesive.  If the 
adhesive coated tape is not applied within approximately 30 minutes, a tack free skin may form, interfering 
with adhesion.  Use extreme caution during application to assure that no adhesive is applied outside the 
bond area if subsequent finishing is required.
2. Wrap one layer of coated tape (with adhesive down) over the joint with a minimum of one inch on each 
duct.  Overlap the tape ends 1 to 2 inches at the tape joint except, that for ducts with nozzle openings, no 
overlap of the tape ends is required.  Pull out wrinkles in the fiberglass tape and smooth out any voids or 
air pockets between the fiberglass tape and the duct.  Apply positive pressure to ensure contact of the 
adhesive to the duct.  A bondline thickness of 0.04 to 0.08 inch is required.  This is approximately 1.5 
ounces of adhesive per foot of 3 inch tape.
3. Allow the adhesive to cure under contact pressure for a minimum of 24 hours at 65 to 100 degrees 
Fahrenheit.  A minimum of 20 percent relative humidity is required for adhesive cure.  If the relative humidity 
falls below 20 percent, extend the cure time sufficiently to assure that there is a total of 24 hours of cure 
with the relative humidity at or above 20 percent.
Material Required
QTY Part Number {Specification} Name
6 feet Style 116 Per BMS 9-3R, Type C, Class
7, slit and sealed, 3 inches nominal
width
Fiberglass Tape (a)
4 ounces BAC5010, Type 98 (GE RTV 133) Adhesive (b)
Vendor Contact Information
(a) See the Qualified Products List at the end of the Boeing Material Specification
(BMS) for supplier data.
(b) General Electric Co. Silicon Products Business Department
Hudson River Road
Waterford, New York, 12188, USA

### Page 46

APPENDIX C: BAC 5412 METHOD VIII - TAPED TELESCOPING JOINTS
August 21, 2003
Revision 2:  November 16, 2006 747-21A2422
BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 46 of 46
BOEING SERVICE BULLETIN 747-21A2422
 
APPENDIX  C:   BAC 5412 METHOD VIII - TAPED TELESCOPING JOINTS
1. Sharp Edges of duct should be smoothed with a file.
2. Telescope the two ducts so that there is at least 1/2 inch overlap of the duct.
3. Clean the area to be taped using cleaning solvents for kevlar/epoxy: Refer to BSOPM 20-30-03, 20-60-01 
or (BAC 5750).
4. Apply two laps of 2 inch wide Venture Tape No. 3959 to the center of the joint, pulling tight and smoothing 
while applying.
Material Required
QTY Part Number {Specification} Name
6 feet Venture Tape No. 3959 Vinyl Plastic Tape (a)
Vendor Contact Information
(a) Venture Tape Corp
30-T Commerce Road
Rockland, Maine 02370, USA
DIAGRAM OF TAPED TELESCOPING JOINTS
TAPE
N26047

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