# Boeing Special Attention Service Bulletin 777-25-0621: Revision 2 - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2020-0586; AD 2020-22-10 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Special Attention Service Bulletin 777-25-0621](https://openairdocs.org/service-documents/boeing/sb-777-25-0621.md) - Title as filed: SB-777-25-0621-02-- - Pages: 88 - PDF: https://openairdocs.org/files/sha256/2b/a5/2ba58f20cc9ea3e202160488ab0bd2f4e75be3ed063e2c7932243e96cad51e40 - Page: https://openairdocs.org/service-documents/boeing/sb-777-25-0621/file/2ba58f20cc9e ## 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 777 Service Bulletin SPECIAL ATTENTION Number: 777-25-0621 Original Issue: December 10, 2014 Revision 2: February 28, 2020 ATA System: 2510 2581 SUBJECT: EQUIPMENT/FURNISHINGS - Flight Compartment - Overhead Panel Support Structure BMS 8-39 Urethane Foam Insulation 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: BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET Copyright © 2014 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 Unpublished Work.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: December 10, 2014 777-25-0621Revision 2: February 28, 2020 1 of 88 3.0 ### Page 2 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 2 of 88 BOEING SERVICE BULLETIN 777-25-0621 BLANK PAGE ### Page 3 Table of Contents Revision Transmittal Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2. Data Supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . . 23 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 M. Software Accomplishment Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 C. Parts Necessary for Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 FIGURE 1: FLIGHT COMPARTMENT - OVERHEAD PANEL - OPEN ACCESS [Group 1, Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 FIGURE 2: FLIGHT COMPARTMENT - OVERHEAD PANEL SUPPORT STRUCTURE, BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT [Group 1, Configuration 1] . . . . . . 50 FIGURE 3: FLIGHT COMPARTMENT - OVERHEAD PANEL - CLOSE ACCESS [Group 1, Configuration 1-2, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 FIGURE 4: FLIGHT COMPARTMENT - OVERHEAD PANEL SUPPORT STRUCTURE - REMOVAL [Group 1, Configuration 1-2, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 FIGURE 5: FLIGHT COMPARTMENT - OVERHEAD PANEL SUPPORT STRUCTURE - INSTALLATION [Group 1, Configuration 1-2, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 3 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 4 FIGURE 6: FLIGHT COMPARTMENT - OVERHEAD PANEL - OPEN ACCESS [Group 1, Configuration 2, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 FIGURE 7: FLIGHT COMPARTMENT - DRIPSHIELD, BMS 8-39 URETHANE FOAM INSULATION - GENERAL VISUAL INSPECTION [Group 1, Configuration 1-2] . . . . . . . . . . . . . . . 67 FIGURE 8: FLIGHT COMPARTMENT - DRIPSHIELD, BMS 8-39 URETHANE FOAM INSULATION - REPLACEMENT [Group 1, Configuration 1-2] . . . . . . . . . . . . . . . . . . . . . . . . 69 FIGURE 9: FLIGHT COMPARTMENT - OVERHEAD PANEL - CLOSE ACCESS [Group 1, Configuration 2, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 FIGURE 10: FLIGHT COMPARTMENT - OVERHEAD PANEL - MORE ACCESS [Group 1, Configuration 2, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 FIGURE 11: FLIGHT COMPARTMENT - OVERHEAD PANEL SUPPORT STRUCTURE, BMS 8-39 URETHANE FOAM INSULATION DETAILED INSPECTION [Group 1, Configuration 2, 4] . 77 FIGURE 12: FLIGHT COMPARTMENT - OVERHEAD PANEL SUPPORT STRUCTURE, BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT [Group 1, Configuration 2, 4] . . . . . 79 APPENDIX A: PART DEMAND INTENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 APPENDIX B: LOGIC DIAGRAM FOR PARAGRAPH 1.E., COMPLIANCE: TABLE 1: OVERHEAD PANEL SUPPORT STRUCTURE BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT AND GENERAL VISUAL INSPECTION OF THE DRIPSHIELD [Group 1, Configuration 1] . . . 83 APPENDIX C: LOGIC DIAGRAM FOR PARAGRAPH 1.E., COMPLIANCE: TABLE 2: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE AND GENERAL VISUAL INSPECTION OF THE DRIPSHIELD FOR BMS 8-39 URETHANE FOAM INSULATION [Group 1, Configuration 2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 APPENDIX D: TYPICAL INSTALLATIONS OF BMS 8-39 URETHANE FOAM INSULATION INSTALLED ON THE DRIPSHIELD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 APPENDIX E: LOGIC DIAGRAM FOR PARAGRAPH 1.E., COMPLIANCE: TABLE 3: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE FOR BMS 8-39 URETHANE FOAM INSULATION [Group 1, Configuration 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 4 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 5 Commercial Airplanes 777 Service Bulletin SPECIAL ATTENTION Revision Transmittal SheetNumber: 777-25-0621Original Issue: December 10, 2014 Revision 2: February 28, 2020 ATA System: 2510 2581 SUBJECT: EQUIPMENT/FURNISHINGS - Flight Compartment - Overhead Panel Support Structure BMS 8-39 Urethane Foam Insulation Replacement This revision includes all pages of the service bulletin. COMPLIANCE INFORMATION RELATED TO THIS REVISION Federal Aviation Administration (FAA) Airworthiness Directive AD 2018-14-02 is related to this service bulletin. Effects of this Revision on airplanes on which the Original Issue or Revision 1 was previously done: ActionConditionGroup 1. Do a Detailed Inspection for BMS 8-39 urethane foam on the overhead panel support structure. 2. Do a General Visual In- spection (GVI) for BMS 8- 39 urethane foam on the dripshield. 3. Replace any BMS 8-39 urethane foam found with BMS 8-371 foam. 4. Do functional tests. Airplanes that have accomplished the Original Issue of this service bulletin only. 1, Configuration 2 1. None.Airplanes that have accomplished Revision 1 of this service bulletin only. 1, Configuration 3 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 5 of 88 ### Page 6 ActionConditionGroup 1. Do a Detailed Inspection for BMS 8-39 urethane foam on the overhead panel support structure. 2. Replace any BMS 8-39 urethane foam found with BMS 8-371 foam. 3. Do functional tests. Airplanes that have accomplished both the Original Issue and Revision 1 of this service bulletin. 1, Configuration 4 See Paragraph 1.D., Description for more information. REASON FOR REVISION This revision is sent to: 1. Provide alternative materials and quantities. 2. Include instructions to remove ducting to access the BMS 8-39 urethane foam on the overhead panel support structure. 3. Provide additional work requirements for airplanes that have accomplished the Original Issue of this service bulletin and may not have removed BMS 8-39 urethane foam insulation completely from the overhead panel support structure. 4. Provide additional tests to verify the functionality of equipment affected by the removal of the overhead panel support structure. These sections were changed: 1. Summary, Background: Changed information. 2. Summary, Action: Added group/configuration applicability. 3. Summary, Compliance: Added FAA AD information. 4. Summary, Illustration: Added group/configuration applicability. 5. Paragraph 1.A., Effectivity: Added group/configuration applicability. 6. Paragraph 1.C., Reason: Background: Added reason for revision statement. 7. Paragraph 1.D., Description: Added group/configuration applicability. 8. Paragraph 1.E., Compliance: Added FAA AD information and new compliance tables. 9. Paragraph 1.F., Approval: Added AMOC paragraph. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 6 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 7 10. Paragraph 1.G., Manpower: Updated manpower information. 11. Paragraph 1.J., References: Updated references. 12. Paragraph 2.A., Material - Price and Availability: Updated footnotes. 13. Paragraph 2.C.1., Kits/Parts: Changed existing part number for self-locking nut. 14. Paragraph 2.C.2., Parts and Materials Supplied by the Operator: Added material dimensions and added group/configuration applicability. 15. Paragraph 3.A., General Information: Added notes for Detailed Inspection and temporary protection. 16. Paragraph 3.B., Work Instructions: Updated instructions for Group 1, Configuration 1 and 2. Created new instructions for Group 1, Configuration 3 and 4. 17. Figure 1 through 9: Added applicability. 18. Figure 1 and 3: Changed AMM reference in step 4. 19. Figure 2: Changed service bulletin number in step 4. 20. Created new Figure 10. 21. Appendix B and C: Updated information. 22. Created new Appendix E. The data given in Information Notice 777-25-0621 IN 01 is included in this revision. The data given in Information Notice 777-25-0621 IN 02 is included in this revision. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity and format changes, to show the location of all content changes. Pages with no vertical lines have no changes. REVISION HISTORY December 10, 2014Original Issue: August 04, 2017Revision 1: February 28, 2020Revision 2: Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 7 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 8 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 8 of 88 BOEING SERVICE BULLETIN 777-25-0621 BLANK PAGE ### Page 9 Commercial Airplanes 777 Service Bulletin SPECIAL ATTENTION SummaryNumber: 777-25-0621Original Issue: December 10, 2014 Revision 2: February 28, 2020 ATA System: 2510 2581 SUBJECT: EQUIPMENT/FURNISHINGS - Flight Compartment - Overhead Panel Support Structure BMS 8-39 Urethane Foam Insulation Replacement BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS DOCUMENT IMMEDIATELY. CONCURRENT REQUIREMENTS None. BACKGROUND Accomplishment of this service bulletin will make sure that the risk of fire in the flight compartment from aging BMS 8-39 urethane foam insulation is decreased. Degraded BMS 8-39 urethane foam insulation on the overhead panel support structure can be an unacceptable fuel source for a fire if exposed to an ignition source. If this service bulletin is not done, degraded BMS 8-39 urethane foam insulation could result in an increased risk of a fire. BMS 8-39 flexible urethane foam insulation has self-extinguishing and physical properties that degrade with age and large parts fabricated from this material present an unacceptable fuel source. BMS 8-39 urethane foam insulation fire retardants are mixed into, but are not chemically connected with, the remaining components of the foam insulation. This condition will cause the fire retardant properties to have decreased effectiveness. The concern is hidden areas where fire cannot easily be detected and suppressed. BMS 8-39 urethane foam insulation in the flight compartment and other areas of the airplanes was replaced in production from line number 507 and Boeing Service Bulletin 777-25-0362 was released to instruct foam insulation replacement for in-service airplanes. However, Boeing has recently found some additional BMS 8-39 urethane foam insulation on the overhead panel support structure in the flight compartment, that was not included in Boeing Service Bulletin 777-25-0362. Since the release of the Original Issue of this service bulletin, BMS 8-39 urethane foam insulation was found on the dripshield above the overhead panel. All BMS 8-39 urethane foam insulation on the overhead panel and if installed on the dripshield, must be removed and replaced with BMS 8-371 polyvinylidene fluoride foam insulation. This service bulletin gives instructions to remove BMS 8-39 urethane foam insulation and install BMS 8-371 polyvinylidene fluoride foam insulation on the overhead panel support structure in the flight compartment. BMS 8-371 polyvinylidene fluoride foam insulation has better fire retardant properties that stay effective with age. Boeing Service Related Problem (SRP) 777-SRP-25-0346 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 777 FTD 25-14003 is related to this service bulletin. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 9 of 88 ### Page 10 As a part of a service bulletin validation program, this change was completed on airplane WB509 by Service Bulletin 777-25-0621 Original Issue before the release of Revision 1 of this service bulletin. The change completed on airplane WB509 is equivalent to accomplishing Revision 1 of this service bulletin. Airplane WB509 has the configuration of a Group 1, Configuration 3 airplane. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information. ReferenceAffectedPlanning Data Paragraph 1.A.2., Spares AffectedNoSpares Affected Paragraph 1.E., ComplianceYesAD Related Paragraph 1.H., Weight and Balance ChangesNoWeight and Balance Change Paragraph 1.I., Electrical Load DataNoElectrical Load Changed Paragraph 1.K., Publications AffectedYesPublications Affected Paragraph 1.K., Publications AffectedNoAirplane Flight Operations Affected (Flight Crew Operations Manual and/or FAA Approved Airplane Flight Manual) Paragraph 2.C.1., Kits/PartsYesKits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator YesOperator Supplied Parts/Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin NoSpecial Tooling Required ACTION Group 1, Configuration 1: Remove the overhead panel support structure and replace the BMS 8-39 urethane foam with BMS 8-371 foam. Inspect for BMS 8-39 urethane foam on the dripshield and replace any found with BMS 8-371 foam. Reinstall the overhead panel support structure and do functional tests. Group 1, Configuration 2: Inspect for BMS 8-39 urethane foam on the overhead panel support structure and the dripshield. If any BMS 8-39 urethane foam is found, remove the overhead panel support structure. Replace any BMS 8-39 urethane foam found on the overhead panel support structure or the dripshield with BMS 8-371 foam. Reinstall the overhead panel support structure and do functional tests. Group 1, Configuration 3: Do functional tests. Group 1, Configuration 4: Inspect for BMS 8-39 urethane foam on the overhead panel support structure. If any BMS 8-39 urethane foam is found, remove the overhead panel support structure. Replace any BMS 8-39 urethane foam found on the overhead panel support structure with BMS 8-371 foam. Reinstall the overhead panel support structure and do functional tests. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 10 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 11 EFFECTIVITY 777-200/200LR/300/300ER Airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. COMPLIANCE Federal Aviation Administration (FAA) Airworthiness Directive AD 2018-14-02 is related to this service bulletin. The effective date of the AD 2018-14-02 is August 13, 2018. Refer to Paragraph 1.E., Compliance. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are not available for the configuration changes given in this service bulletin. MANPOWER Refer to Paragraph 1.G., Manpower. MATERIAL INFORMATION Boeing Supplied Kits/Parts. Refer to Paragraph 2.A., Material - Price and Availability. Operators are encouraged to complete the survey provided in APPENDIX A of this service bulletin to help Boeing predict the quantity and timing of the Boeing Supplied Kits/Parts. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 11 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 12 (OCR) BOEING SERVICE BULLETIN 777-25-0621 GROUP 1, CONFIGURATION 1: REMOVE THE OVERHEAD PANEL SUPPORT STRUCTURE AND REPLACE THE BMS 8-39 URETHANE FOAM WITH BMS 8-371 FOAM. INSPECT FOR BMS 8-39 URETHANE FOAM ON THE DRIPSHIELD AND REPLACE ANY FOUND WITH BMS 8-371 FOAM. REINSTALL THE OVERHEAD PANEL SUPPORT STRUCTURE AND DO FUNCTIONAL TESTS. GROUP 1, CONFIGURATION 2: INSPECT FOR BMS 8-39 FOAM ON THE OVERHEAD PANEL SUPPORT STRUCTURE AND THE DRIPSHIELD. IF ANY BMS 8-39 FOAM IS FOUND, REMOVE THE OVERHEAD PANEL SUPPORT STRUCTURE. REPLACE ANY BMS 8-39 FOAM FOUND ON THE OVERHEAD PANEL SUPPORT STRUCTURE OR THE DRIPSHIELD WITH BMS 8-371 FOAM. REINSTALL THE OVERHEAD PANEL SUPPORT STRUCTURE AND DO FUNCTIONAL TESTS. FLIGHT COMPARTMENT GROUP 1, CONFIGURATION 3: DO FUNCTIONAL TESTS. GROUP 1, CONFIGURATION 4: INSPECT FOR BMS 8-39 FOAM ON THE OVERHEAD PANEL SUPPORT STRUCTURE. IF ANY BMS 8-39 FOAM IS FOUND, REMOVE THE OVERHEAD PANEL SUPPORT STRUCTURE. REPLACE ANY BMS 8-39 FOAM FOUND ON THE OVERHEAD PANEL SUPPORT STRUCTURE WITH BMS 8-371 FOAM REINSTALL THE OVERHEAD PANEL SUPPORT STRUCTURE AND DO FUNCTIONAL TESTS. OVERHEAD PANEL SUPPORT STRUCTURE 2376182 (WIRE BUNDLES AND MODULES NOT SHOWN) Original Issue: December 10, 2014 Revision 2: February 28, 2020 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished 777-25-0621 Work - See page 1 for details. 12 of 88 ### Page 13 Commercial Airplanes 777 Service Bulletin SPECIAL ATTENTION Number: 777-25-0621 Original Issue: December 10, 2014 Revision 2: February 28, 2020 ATA System: 2510 2581 SUBJECT: EQUIPMENT/FURNISHINGS - Flight Compartment - Overhead Panel Support Structure BMS 8-39 Urethane Foam Insulation Replacement BOEING RECOMMENDS THAT EACH OPERATOR EXAMINE THIS DOCUMENT IMMEDIATELY. 1. PLANNING INFORMATION A. Effectivity 1. Airplanes This bulletin is applicable to 777-200, 777-200LR, 777-300, 777-300ER Airplane(s), line number(s) 1-506 in 1 Group(s). Where the effectivity is presented with hyphens between line numbers, the airplane applicability means "through" and "inclusive", e.g. line numbers 1-9 means line numbers 1 through 9 inclusive. Refer to Service Bulletin Index D624W001 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is applicable to 777-200/200LR/300/300ER Airplanes, line numbers 1-506, in 1 Group. The Variable Numbers and Group Information for the applicable airplanes is given below. An equivalent change is on subsequent production airplanes. Refer to PRR 62777-37S for data about this change. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 13 of 88 ### Page 14 DESCRIPTIONCONFIGURATIONGROUP 777-200/-200LR/-300/-300ER Airplanes that have BMS 8-39 urethane foam insulation installed on the overhead support structure and the dripshield in the flight compartment. -1 Airplanes that have not accomplished this service bulletin.1 Airplanes that have accomplished the Original Issue of this service bulletin only. 2 Airplanes that have accomplished Revision 1 of this service bulletin only. 3 Airplanes that have accomplished the Original Issue and Revision 1 of this service bulletin. 4 Airplane Models: 777-200, 777-200LR, 777-300, 777-300ER GroupVariable Number 1WA001 - WA017 1WA076 - WA080 1WA086 - WA093 1WA101 - WA104 1WA116 - WA119 1WA131 - WA137 1WA171 - WA175 1WA196 - WA198 1WA206 - WA212 1WA221 - WA223 1WA231 - WA232 1WA241 - WA250 1WA261 - WA266 1WA281 1WA301 - WA302 1WB001 - WB021 1WB031 - WB046 1WB051 - WB088 GroupVariable Number 1WB101 - WB106 1WB121 - WB125 1WB131 - WB139 1WB151 - WB155 1WB161 - WB177 1WB181 - WB194 1WB201 - WB215 1WB231 - WB247 1WB271 - WB273 1WB276 - WB286 1WB291 - WB302 1WB306 - WB307 1WB311 - WB337 1WB341 - WB342 1WB366 - WB367 1WB371 - WB388 1WB406 1WB411 - WB413 GroupVariable Number 1WB416 - WB437 1WB446 - WB453 1WB476 1WB481 - WB484 1WB501 - WB510 1WB531 - WB537 1WB551 - WB554 1WB591 - WB597 1WB601 - WB606 1WB611 - WB621 1WB631 - WB638 1WB646 - WB649 1WC051 - WC073 1WC101 - WC104 1WC111 - WC115 1WC241 - WC243 1WC281 - WC290 1WC301 - WC306 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 14 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 15 GroupVariable Number 1WC361 - WC362 1WC371 - WC374 1WC381 - WC390 1WC441 GroupVariable Number 1WC446 - WC448 1WC456 1WD001 1WD501 - WD502 GroupVariable Number 1WD521 - WD529 1WD561 1WD621 -- 2. Spares Affected None. B. Concurrent Requirements None. C. Reason Accomplishment of this service bulletin will make sure that the risk of fire in the flight compartment from aging BMS 8-39 urethane foam insulation is decreased. Degraded BMS 8-39 urethane foam insulation on the overhead panel support structure can be an unacceptable fuel source for a fire if exposed to an ignition source. If this service bulletin is not done, degraded BMS 8-39 urethane foam insulation could result in an increased risk of a fire. BMS 8-39 flexible urethane foam insulation has self-extinguishing and physical properties that degrade with age and large parts fabricated from this material present an unacceptable fuel source. BMS 8-39 urethane foam insulation fire retardants are mixed into, but are not chemically connected with, the remaining components of the foam insulation. This condition will cause the fire retardant properties to have decreased effectiveness. The concern is hidden areas where fire cannot easily be detected and suppressed. BMS 8-39 urethane foam insulation in the flight compartment and other areas of the airplanes was replaced in production from line number 507 and Boeing Service Bulletin 777-25-0362 was released to instruct foam insulation replacement for in-service airplanes. However, Boeing has recently found some additional BMS 8-39 urethane foam insulation on the overhead panel support structure in the flight compartment, that was not included in Boeing Service Bulletin 777-25-0362. Since the release of the Original Issue of this service bulletin, BMS 8-39 urethane foam insulation was found on the dripshield above the overhead panel. All BMS 8-39 urethane foam insulation on the overhead panel and if installed on the dripshield, must be removed and replaced with BMS 8-371 polyvinylidene fluoride foam insulation. This service bulletin gives instructions to remove BMS 8-39 urethane foam insulation and install BMS 8-371 polyvinylidene fluoride foam insulation on the overhead panel support structure in the flight compartment. BMS 8-371 polyvinylidene fluoride foam insulation has better fire retardant properties that stay effective with age. Boeing Service Related Problem (SRP) 777-SRP-25-0346 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 777 FTD 25-14003 is related to this service bulletin. As a part of a service bulletin validation program, this change was completed on airplane WB509 by Service Bulletin 777-25-0621 Original Issue before the release of Revision 1 of this service bulletin. The change completed on airplane WB509 is equivalent to accomplishing Revision 1 of this service bulletin. Airplane WB509 has the configuration of a Group 1, Configuration 3 airplane. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 15 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 16 Revision 1 was sent to incorporate results from the service bulletin validation. The validation found that foam insulation replacement could not be done without the removal of the overhead panel support structure from the flight compartment ceiling. Removal and installation instructions were added to this service bulletin. This revision also added work instructions which included tests of modules and a General Visual Inspection (GVI) of the dripshield for BMS 8-39 urethane foam insulation. Revision 2 is sent to: 1. Provide alternative materials and quantities. 2. Include instructions to remove ducting to access the BMS 8-39 urethane foam on the overhead panel support structure. 3. Provide additional work requirements for airplanes that have accomplished the Original Issue of this service bulletin and may not have removed BMS 8-39 urethane foam completely from the overhead panel support structure. 4. Provide additional tests necessary to verify the functionality of equipment affected by the removal of the overhead panel support structure. D. Description Group 1, Configuration 1: Remove the overhead panel support structure and replace the BMS 8-39 urethane foam with BMS 8-371 foam. Inspect for BMS 8-39 urethane foam on the dripshield and replace any found with BMS 8-371 foam. Reinstall the overhead panel support structure and do functional tests. Group 1, Configuration 2: Inspect for BMS 8-39 urethane foam on the overhead panel support structure and the dripshield. If any BMS 8-39 urethane foam is found, remove the overhead panel support structure. Replace any BMS 8-39 urethane foam found on the overhead panel support structure or the dripshield with BMS 8-371 foam. Reinstall the overhead panel support structure and do functional tests. Group 1, Configuration 3: Do functional tests. Group 1, Configuration 4: Inspect for BMS 8-39 urethane foam on the overhead panel support structure. If any BMS 8-39 urethane foam is found, remove the overhead panel support structure. Replace any BMS 8-39 urethane foam found on the overhead panel support structure with BMS 8-371 foam. Reinstall the overhead panel support structure and do functional tests. Effects of this Revision on airplanes on which the Original Issue or Revision 1 was previously done: Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 16 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 17 ActionConditionGroup 1. Do a Detailed Inspection for BMS 8-39 urethane foam on the overhead panel support structure. 2. Do a General Visual In- spection (GVI) for BMS 8- 39 urethane foam on the dripshield. 3. Replace any BMS 8-39 urethane foam found with BMS 8-371 foam. 4. Do functional tests. Airplanes that have accomplished the Original Issue of this service bulletin only. 1, Configuration 2 1. None.Airplanes that have accomplished Revision 1 of this service bulletin only. 1, Configuration 3 1. Do a Detailed Inspection for BMS 8-39 urethane foam on the overhead panel support structure. 2. Replace any BMS 8-39 urethane foam found with BMS 8-371 foam. 3. Do functional tests. Airplanes that have accomplished both the Original Issue and Revision 1 of this service bulletin. 1, Configuration 4 The work in this service bulletin is done in the maintenance zone(s) given below. Affected Maintenance Zones ZoneModel 211, 212777-200, 777-200LR, 777-300, 777-300ER E. Compliance Federal Aviation Administration (FAA) Airworthiness Directive AD 2018-14-02 is related to this service bulletin. The effective date of the AD 2018-14-02 is August 13, 2018. Accomplish the required action(s), based on the applicable condition(s) in Table(s) 1-3, in accordance with Paragraph 3. Accomplishment Instructions. A logic diagram showing compliance tasks and compliance times is included as an aid in APPENDIX B, APPENDIX C and APPENDIX E. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 17 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 18 Group 1, Configuration 1: Table 1: OVERHEAD PANEL SUPPORT STRUCTURE BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT AND GENERAL VISUAL INSPECTION OF THE DRIPSHIELD Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 72 months after the effective date of AD 2018- 14-02. Do PART 1: OVERHEAD PANEL SUPPORT STRUCTURE BMS 8-39 URETHANE FOAM INSU- LATION REPLACEMENT All airplanes Do PART 2: GENERAL VISUAL INSPECTION OF THE DRIPSHIELD --No further action re- quired. CONDITION 1: BMS 8-39 URETHANE FOAM INSU- LATION IS NOT FOUND DURING PART 2 INSPEC- TION -Before further flight. Do PART 3: DRIP- SHIELD BMS 8-39 URE- THANE FOAM INSULA- TION REPLACEMENT CONDITION 2: BMS 8-39 URETHANE FOAM INSU- LATION IS FOUND DUR- ING PART 2 INSPECTION Group 1, Configuration 2: Table 2: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE AND GENERAL VISUAL INSPECTION OF THE DRIPSHIELD FOR BMS 8-39 URETHANE FOAM INSULA- TION Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 72 months after the Revision 2 date of this ser- vice bulletin. Do PART 2: GENERAL VISUAL INSPECTION OF THE DRIPSHIELD All airplanes Do PART 5: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE --No further action re- quired. CONDITION 3: BMS 8-39 URETHANE FOAM INSU- LATION IS NOT FOUND DURING PART 2 AND PART 5 INSPECTION Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 18 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 19 Group 1, Configuration 2: Table 2: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE AND GENERAL VISUAL INSPECTION OF THE DRIPSHIELD FOR BMS 8-39 URETHANE FOAM INSULA- TION Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before further flight. Do PART 1: OVERHEAD PANEL SUPPORT STRUCTURE BMS 8-39 URETHANE FOAM INSU- LATION REPLACEMENT CONDITION 4: BMS 8-39 URETHANE FOAM INSU- LATION IS FOUND DUR- ING PART 5 INSPECTION (a) Before further flight. Do PART 3: DRIP- SHIELD BMS 8-39 URE- THANE FOAM INSULA- TION REPLACEMENT CONDITION 5: BMS 8-39 URETHANE FOAM INSU- LATION IS FOUND DUR- ING PART 2 INSPECTION (a) (a) Multiple conditions can apply. Group 1, Configuration 4: Table 3: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE FOR BMS 8-39 URETHANE FOAM INSULATION Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 72 months after the Revision 2 date of this ser- vice bulletin. Do PART 5: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE All airplanes --No further action re- quired. CONDITION 6: BMS 8-39 URETHANE FOAM INSU- LATION IS NOT FOUND DURING PART 5 INSPEC- TION -Before further flight. Do PART 1: OVERHEAD PANEL SUPPORT STRUCTURE BMS 8-39 URETHANE FOAM INSU- LATION REPLACEMENT CONDITION 7: BMS 8-39 URETHANE FOAM INSU- LATION IS FOUND DUR- ING PART 5 INSPECTION 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. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 19 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 20 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. The manager of the FAA Seattle ACO Branch approves the accomplishment of the change defined in this SB revision as an alternative method of compliance (AMOC) to accomplishing SB 777-25-0621, Revision 1, for paragraph (g) of AD 2018-14-02. 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 task 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 inspect the work • Time to cure the materials • Time to make the parts • Time to find the tools. Group 1, Configuration 1: OVERHEAD PANEL SUPPORT STRUCTURE BMS 8-39 URETHANE FOAM INSULATION REPLACE- MENT AND GENERAL VISUAL INSPECTION OF THE DRIPSHIELD Elapsed HoursTask HoursNumber of PersonsTask 1.002.002Open Access 1.853.702FIGURE 1 0.622.504FIGURE 4 3.757.502FIGURE 2 0.250.251FIGURE 7 1.503.002FIGURE 8(a) 0.622.54FIGURE 5 3.156.302FIGURE 3 2.304.602Test (PART 4) 62.65(b)62.651Test (PART 6 and 7)(a) 1.002.002Close Access 14.5531.35TOTAL FOR EACH AIRPLANE (a) Add the hours of this task to the total for each airplane based on the results of inspection for BMS 8-39 urethane foam. (b) Elapsed hours may vary depending on number of persons assigned to do the tests. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 20 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 21 Group 1, Configuration 2: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE AND GENERAL VISUAL INSPECTION OF THE DRIPSHIELD FOR BMS 8-39 URETHANE FOAM INSULATION Elapsed HoursTask HoursNumber of PersonsTask 1.002.002Open Access 1.501.501FIGURE 6 0.250.251FIGURE 7 3.757.502FIGURE 11 1.501.501FIGURE 9(a) 1.853.702FIGURE 10(a) 0.622.504FIGURE 4(a) 3.757.502FIGURE 12(a) 1.503.002FIGURE 8(a) 0.622.504FIGURE 5(a) 3.156.302FIGURE 3(a) 2.304.602Test (PART 4) 62.65(b)62.651Test (PART 6 and 7)(a) 1.002.002Close Access 9.8017.85TOTAL FOR EACH AIRPLANE (a) Add the hours of this task to the total for each airplane based on the results of inspection for BMS 8-39 urethane foam. (b) Elapsed hours may vary depending on number of persons assigned to do the tests. Group 1, Configuration 3: FUNCTIONAL TESTS AFTER RE-INSTALLATION OF OVERHEAD PANEL SUPPORT STRUCTURE Elapsed HoursTask HoursNumber of PersonsTask 62.65(a)62.651Test (PART 6 and 7) 62.6562.65TOTAL FOR EACH AIRPLANE (a) Elapsed hours may vary depending on number of persons assigned to do the tests. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 21 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 22 Group 1, Configuration 4: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE FOR BMS 8-39 URETHANE FOAM INSULATION Elapsed HoursTask HoursNumber of PersonsTask 1.002.002Open Access 1.501.501FIGURE 6 3.757.502FIGURE 11 1.501.501FIGURE 9(a) 1.853.702FIGURE 10(a) 0.622.504FIGURE 4(a) 3.757.502FIGURE 12(a) 0.622.504FIGURE 5(a) 3.156.302FIGURE 3(a) 2.304.602Test (PART 4) 62.65(b)62.651Test (PART 6 and 7)(a) 1.002.002Close Access 9.5517.60TOTAL FOR EACH AIRPLANE (a) Add the hours of this task to the total for each airplane based on the results of inspection for BMS 8-39 urethane foam. (b) Elapsed hours may vary depending on number of persons assigned to do the tests. H. Weight and Balance Changes None. I. Electrical Load Data Not changed. J. References 1. Existing Data: a. Boeing Service Bulletin 777-25-0362 b. Boeing Service Related Problem (SRP) 777-SRP-25-0346 c. Engineering Change Memo PRR 62777-37S d. Engineering Change Memo MRR 725014-013S Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 22 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 23 e. Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2018-14-02 f. Service Bulletin Index D624W001 g. Standard Overhaul Practices Manual (SOPM) 20-11-03, 20-30-03, 20-50-10 h. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-19 i. 777 Aircraft Maintenance Manual (AMM) 21-31-03, 21-44-09, 21-60-01, 21-61-04, 22-11-01, 22-11-02, 22-31-00, 23-11-05, 23-12-01, 23-21-01, 23-24-00, 23-24-03, 23-51-04, 23-71-00, 23-71-02, 23-71-04, 23-93-00, 23-93-01, 23-93-02, 24-09-00, 24-22-00, 24-22-01, 24-30-00, 25-15-06, 26-11-00, 26-16-00, 26-21-00, 26-22-00, 26-22-03, 26-22-04, 26-23-00, 27-02-02, 27-02-03, 27-02-32, 28-22-00, 28-22-17, 29-11-00, 29-11-01, 29-11-02, 29-11-10, 29-11-80, 29-21-00, 30-11-00, 30-21-00, 30-41-00, 30-41-02, 30-41-12, 30-42-00, 31-25-01, 31-51-00, 31-51-02, 32-09-00, 32-31-00, 32-31-01, 32-44-00, 33-11-00, 33-13-00, 33-14-00, 33-16-00, 33-42-00, 33-51-00, 34-13-00, 34-24-01, 34-24-02, 34-43-00, 34-45-00, 34-51-00, 34-53-00, 34-55-00, 34-57-00, 35-22-00, 36-11-10, 36-11-20, 45-10-01, 45-11-05, 46-11-02, 46-11-04, 46-11-07, 46-13-01, 49-11-00, 52-51-00, 71-00-00, 73-00-00, 73-21-00, 76-11-00 j. 777 Fleet Team Digest (FTD) 25-14003 2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: TitleDrawing Number SUPPORT INSTL-OVERHEAD PANEL233W3300 The table above lists applicable drawings used to prepare this service bulletin. The drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. The drawings may not be applicable to all airplane configurations or operators. K. Publications Affected 1. Publications: Chapter-SectionPublication 21-22, 25-10, 33-11777 Illustrated Parts Catalog 53-17777 Aircraft Maintenance Manual - Prac- tices and Procedures 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin does not affect FCS, therefore DTIs are not necessary. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 23 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 24 L. Interchangeability and Intermixability of Parts Refer to Paragraph 2.C., Parts Necessary for Each Airplane, for interchangeability and intermixability information. M. Software Accomplishment Summary Not affected. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 24 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 25 2. MATERIAL INFORMATION A. Material - Price and Availability Boeing can supply the kits/parts shown in Paragraph 2.C., Parts Necessary for Each Airplane. Operators are encouraged to share schedule requirements with Boeing for incorporation of the service bulletin. The kits/parts are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. Prices are in United States Dollars. Terms: Net 30 days. Reference this service bulletin and submit your purchase order by one of these methods: 1. Order on-line via ATA Spec 2000 or The Boeing PART Page 2. Fax to (206) 662-7145 Group 1, Configuration 1: REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION Unit Price as of the Revision 2 date of this Ser- vice Bulletin (US Dollars) ROLT as of the Revision 2 date of this Service Bul- letin (Calendar Days) QTYDateNameKit/Part Num- ber $5,840.001291July 24, 2014TOP KIT, RETROFIT - BMS 8-39 FOAM IN FLIGHT DECK OVER- HEAD - REPLACE- MENT 005W0025-1(b) 25February 17, 2015 24March 17, 2015 25April 14, 2015 $0.43---NUT, SELF-LOCKINGBACN11AG4 (a) (a) It is necessary to remove and replace the self-locking nuts in accordance with FIGURE 4 and FIGURE 5. (b) This kit contains shelf life items. Boeing recommends that operators consider the shelf life of the kit when planning for service bulletin incorporation and kit ordering. Operators are encouraged to complete the survey provided in APPENDIX A of this service bulletin to help Boeing predict the quantity and timing of the Boeing Supplied Kits/Parts. B. Industry Support Information Boeing warranty remedies are not available for the configuration changes given in this service bulletin. C. Parts Necessary for Each Airplane 1. Kits/Parts To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 25 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 26 NOTE: One top kit and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, are necessary for each airplane. The Top Kit is divided into Figure kits for each installation figure shown in the table below. Group 1, Configuration 1: Figure Kit 2Top Kit 1005W0025-1 Group 1, Configuration 1: KIT 005W0025-1 Notes Existing Part NumberName Figure New Part Number 2 Qty (a)(b)233W3307-1INSULATION1233W3307-27 (a)(b)233W3307-2INSULATION1233W3307-28 (a)(b)233W3307-11INSULATION1233W3307-29 (a)(b)233W3307-8INSULATION1233W3307-30 (a)(b)233W3307-4INSULATION1233W3307-31 (a)(b)233W3307-4INSULATION1233W3307-32 (a)(b)233W3307-6INSULATION1233W3307-33 (a)(b)233W3307-6INSULATION1233W3307-34 (a)(b)233W3307-3INSULATION1233W3307-35 (a)(b)233W3307-3INSULATION1233W3307-36 (a)(b)233W3307-5INSULATION1233W3307-37 (a)(b)233W3307-5INSULATION1233W3307-38 (a)(b)233W3307-7INSULATION1233W3307-39 (a)(b)233W3307-7INSULATION1233W3307-40 (a)(b)233W3307-9INSULATION1233W3307-41 (a) Discard the existing part. (b) You cannot use the existing part to replace the new or changed part. Parts NotesExisting Part Number NameQTYNew Part Number (a)BACN11AG4NUT, SELF-LOCKING2BACN11AG4 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 26 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 27 Parts NotesExisting Part Number NameQTYNew Part Number (a) Discard the existing part. 2. Parts and Materials Supplied by the Operator The following parts or materials are necessary to do the change in this service bulletin. Parts and materials in the manuals given in Paragraph 1.J., References, can also be necessary. Examine operator part and material supply to make sure all necessary parts and materials are available. Group 1, Configuration 1-2: NotesNameQTYPart Number / Specification (a)Tape1 RollBMS 5-157, Type I, Class 1, Grade A, Form 1, Composition MPVF (a)(b)(c)Polyvinylidene Fluoride Foam Insulation 1 SheetBMS 8-371, Type 1A, Class 1, Grade 2, 0.25" thick, 36"x36" (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Minimum quantity given. More material may be necessary. (c) BMS 8-371, Type 1, Class 1, Grade 2 Foam Insulation with BMS 5-123 Type 1 or BMS 5-30 Type 1 Adhesive is an acceptable alternative. Group 1, Configuration 2, 4: NotesNameQTYPart Number / Specification (a)(b)(c)Polyvinylidene Fluoride Foam Insulation As requiredBMS 8-371, Type 1A, Class 1, Grade 2, 0.25" thick (a)(b)(c)Polyvinylidene Fluoride Foam Insulation As requiredBMS 8-371, Type 1A, Class 1, Grade 2, 0.125" thick (a) Refer to the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) This material is required if any BMS 8-39 urethane foam is found during PART 5 inspection. The amount of material necessary depends on the amount of BMS 8-39 urethane foam that is found and removed. Refer to Figure 12. (c) BMS 8-371, Type 1, Class 1, Grade 2 Foam Insulation with BMS 5-123 Type 1 or BMS 5-30 Type 1 Adhesive is an acceptable alternative. 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. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 27 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 28 NotesNew Part NumberNameQTYExisting Part Number (a)(b)-OVERHEAD ASSY1233W3311-1, -2, -3, -4, -14, -16 or -17 (a) Make the change in accordance with this service bulletin. (b) There is no equivalent Boeing part number for the changed part. 4. Parts Removed and Not Replaced None. D. Parts Necessary to Change Spares None. 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. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 28 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 29 3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION 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. CAUTION NOTE: 1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 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 – 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 777 Structural Repair Manual, Chapter 51. — Values for airframe maintenance tasks are included in Chapter 20 of 777 Aircraft Maintenance Manual (AMM). — Values for electrical maintenance tasks are included in Chapter 20 of Standard Wiring Practices Manual (SWPM). 4. Use the approved fastener, process and material substitutions in accordance with SRM Chapter 51. 5. Refer to the SWPM 20-10-11 and SWPM 20-10-12 for the wire installation procedures, and SWPM 20-10-19 for the wire separation requirements, as accepted procedures. 6. The necessary conditions for selection of clamp type and size are included in SWPM 20-10-12. If any wire bundle support clamp specified in this service bulletin does not make a correct fit on the wire bundle, refer to SWPM 20-10-12 as an accepted procedure to select a clamp that fits correctly. 7. A General Visual Inspection is defined as: A visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 29 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 30 8. 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. 9. 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. 10. Refer to APPENDIX B, APPENDIX C and APPENDIX E for logic diagram(s). Logic diagrams are provided as an aid only. Information contained in Paragraph 1.E., Compliance is the primary source for compliance times. Information in Paragraph 3.B., Work Instructions is the primary source for tasks required for compliance. 11. 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. 12. 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. 13. Use of colors in Figures is based on guidance from the ATA e-Business Program (ATA) iSpec 2200. 14. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS are in Paragraph 1.E., Compliance. 15. Some steps in the Work Instructions are labeled as Required for Compliance (RC). If this service bulletin is mandated by an Airworthiness Directive (AD), then the steps labeled as "RC", including sub-steps under an RC step and any figures identified in an RC step, must be done to comply with the AD. If a step or sub-step is labeled "RC Exempt" then the RC requirement is removed from that step or sub-step. An Alternative Method of Compliance (AMOC) is required for any deviations to RC steps, including sub-steps and identified figures. Steps not labeled as RC 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 RC steps, including sub-steps and identified figures, can still be done as specified, and the airplane can be put back in an airworthy condition. 16. Use a temporary protective sheet when removing BMS 8-39 urethane foam from the overhead panel support structure to prevent BMS 8-39 urethane foam particles falling into the electrical equipment below. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 30 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 31 B. WORK INSTRUCTIONS Group 1, Configuration 1: OVERHEAD PANEL SUPPORT STRUCTURE BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT AND GENERAL VISUAL INSPECTION OF THE DRIPSHIELD 1. Remove electrical power from the airplane. Refer to 777 AMM 24-22-00 as an acceptable procedure. 2. Get access to the flight compartment. 3. Remove the overhead linings. a. Remove and keep the left and right overhead lining. Refer to 777 AMM 25-15-06 as an accepted procedure. b. Remove and keep the overhead lining panel aft of the overhead panel support structure to get additional access. 4. Remove and keep modules from the overhead panel to get access to the overhead panel support structure in accordance with FIGURE 1. 5. Remove and keep the overhead panel support structure in accordance with FIGURE 4. a. After removal, remove and keep any ducts on the overhead panel support structure necessary to gain access to the BMS 8-39 urethane foam. 6. RC - Do PART 1: OVERHEAD PANEL SUPPORT STRUCTURE BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT 7. RC - Do PART 2: GENERAL VISUAL INSPECTION OF THE DRIPSHIELD for any BMS 8-39 urethane foam. a. CONDITION 1: BMS 8-39 URETHANE FOAM INSULATION IS NOT FOUND DURING PART 2 INSPECTION (1) No further action required. b. CONDITION 2: BMS 8-39 URETHANE FOAM INSULATION IS FOUND DURING PART 2 INSPECTION (1) Do PART 3: DRIPSHIELD BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT 8. Install the kept overhead panel support structure in accordance with FIGURE 5. a. Before installation, re-install kept ducts on the overhead panel support structure that were removed to gain access to the BMS 8-39 urethane foam. 9. Close access in accordance with FIGURE 3. 10. Install the overhead linings. a. Install the kept left and right overhead lining. Refer to 777 AMM 25-15-06 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 31 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 32 b. Install the kept overhead lining aft of the overhead panel support structure. 11. Supply electrical power to the airplane. Refer to 777 AMM 24-22-00 as an acceptable procedure. 12. Do the tests in accordance with PART 4: OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES. 13. Do the tests in accordance with PART 6: ADDITIONAL OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES. 14. Do the tests in accordance with PART 7: TESTS OF THE EQUIPMENT AFFECTED BY THE REMOVAL OF THE OVERHEAD PANEL SUPPORT STRUCTURE. 15. Put the airplane back to a serviceable condition. Group 1, Configuration 2: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE AND GENERAL VISUAL INSPECTION OF THE DRIPSHIELD FOR BMS 8-39 URETHANE FOAM INSULATION 1. Remove electrical power from the airplane. Refer to 777 AMM 24-22-00 as an acceptable procedure. 2. Get access to the flight compartment. 3. Remove and keep modules from the overhead panel to get access to see the dripshield and the overhead panel support structure in accordance with FIGURE 6. 4. Remove the overhead linings. a. Remove and keep the left and right overhead lining. Refer to 777 AMM 25-15-06 as an accepted procedure. b. Remove and keep the overhead lining panel aft of the overhead panel support structure to get additional access. 5. RC - Do PART 2: GENERAL VISUAL INSPECTION OF THE DRIPSHIELD and do PART 5: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE for any BMS 8-39 urethane foam. a. CONDITION 3: BMS 8-39 URETHANE FOAM INSULATION IS NOT FOUND DURING PART 2 AND PART 5 INSPECTION (1) No further action required. (2) RC Exempt - Close access in accordance with FIGURE 9. (3) RC Exempt - Install the overhead linings. (a) Install the kept left and right overhead lining. Refer to 777 AMM 25-15-06 as an accepted procedure. (b) Install the kept overhead lining aft of the overhead panel support structure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 32 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 33 (4) RC Exempt - Supply electrical power to the airplane. Refer to 777 AMM 24-22-00 as an acceptable procedure. (5) RC Exempt - Do the tests in accordance with PART 4: OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES. b. CONDITION 4: BMS 8-39 URETHANE FOAM INSULATION IS FOUND DURING PART 5 INSPECTION NOTE: Multiple conditions can apply. (1) RC Exempt - Remove and keep modules from the overhead panel to get access to the overhead panel support structure in accordance with FIGURE 10. (2) RC Exempt - Remove and keep the overhead panel support structure in accordance with FIGURE 4. (a) After removal, remove and keep any ducts on the overhead panel support structure necessary to gain access to the BMS 8-39 urethane foam. (3) Do PART 1: OVERHEAD PANEL SUPPORT STRUCTURE BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT (4) RC Exempt - Install the kept overhead panel support structure in accordance with FIGURE 5. (a) Before installation, re-install kept ducts on the overhead panel support structure that were removed to gain access to the BMS 8-39 urethane foam. (5) RC Exempt - Close access in accordance with FIGURE 3. (6) RC Exempt - Install the overhead linings. (a) Install the kept left and right overhead lining. Refer to 777 AMM 25-15-06 as an accepted procedure. (b) Install the kept overhead lining aft of the overhead panel support structure. (7) RC Exempt - Supply electrical power to the airplane. Refer to 777 AMM 24-22-00 as an acceptable procedure. (8) RC Exempt - Do the tests in accordance with PART 4: OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES. (9) RC Exempt - Do the tests in accordance with PART 6: ADDITIONAL OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES. (10) RC Exempt - Do the tests in accordance with PART 7: TESTS OF THE EQUIPMENT AFFECTED BY THE REMOVAL OF THE OVERHEAD PANEL SUPPORT STRUCTURE. c. CONDITION 5: BMS 8-39 URETHANE FOAM INSULATION IS FOUND DURING PART 2 INSPECTION Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 33 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 34 NOTE: Multiple conditions can apply. (1) RC Exempt - Remove and keep modules from the overhead panel to get access to the overhead panel support structure in accordance with FIGURE 10. (2) RC Exempt - Remove and keep the overhead panel support structure in accordance with FIGURE 4. (3) Do PART 3: DRIPSHIELD BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT (4) RC Exempt - Install the kept overhead panel support structure in accordance with FIGURE 5. (5) RC Exempt - Close access in accordance with FIGURE 3. (6) RC Exempt - Install the overhead linings. (a) Install the kept left and right overhead lining. Refer to 777 AMM 25-15-06 as an accepted procedure. (b) Install the kept overhead lining aft of the overhead panel support structure. (7) RC Exempt - Supply electrical power to the airplane. Refer to 777 AMM 24-22-00 as an acceptable procedure. (8) RC Exempt - Do the tests in accordance with PART 4: OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES. (9) RC Exempt - Do the tests in accordance with PART 6: ADDITIONAL OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES. (10) RC Exempt - Do the tests in accordance with PART 7: TESTS OF THE EQUIPMENT AFFECTED BY THE REMOVAL OF THE OVERHEAD PANEL SUPPORT STRUCTURE. 6. Put the airplane back to a serviceable condition. Group 1, Configuration 3: FUNCTIONAL TESTS AFTER RE-INSTALLATION OF OVERHEAD PANEL SUPPORT STRUCTURE 1. Get access to the flight compartment. 2. Supply electrical power to the airplane. Refer to 777 AMM 24-22-00 as an acceptable procedure. 3. Do the tests in accordance with PART 6: ADDITIONAL OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES. 4. Do the tests in accordance with PART 7: TESTS OF THE EQUIPMENT AFFECTED BY THE REMOVAL OF THE OVERHEAD PANEL SUPPORT STRUCTURE. 5. Put the airplane back to a serviceable condition. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 34 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 35 Group 1, Configuration 4: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE FOR BMS 8-39 URETHANE FOAM INSULATION 1. Remove electrical power from the airplane. Refer to 777 AMM 24-22-00 as an acceptable procedure. 2. Get access to the flight compartment. 3. Remove and keep modules from the overhead panel to get access to see the overhead panel support structure in accordance with FIGURE 6. 4. Remove the overhead linings. a. Remove and keep the left and right overhead lining. Refer to 777 AMM 25-15-06 as an accepted procedure. b. Remove and keep the overhead lining panel aft of the overhead panel support structure to get additional access. 5. RC - Do PART 5: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE for any BMS 8-39 urethane foam. a. CONDITION 6: BMS 8-39 URETHANE FOAM INSULATION IS NOT FOUND DURING PART 5 INSPECTION (1) No further action required. (2) RC Exempt - Close access in accordance with FIGURE 9. (3) RC Exempt - Install the overhead linings. (a) Install the kept left and right overhead lining. Refer to 777 AMM 25-15-06 as an accepted procedure. (b) Install the kept overhead lining aft of the overhead panel support structure. (4) RC Exempt - Supply electrical power to the airplane. Refer to 777 AMM 24-22-00 as an acceptable procedure. (5) RC Exempt - Do the tests in accordance with PART 4: OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES. b. CONDITION 7: BMS 8-39 URETHANE FOAM INSULATION IS FOUND DURING PART 5 INSPECTION (1) RC Exempt - Remove and keep modules from the overhead panel to get access to the overhead panel support structure in accordance with FIGURE 10. (2) RC Exempt - Remove and keep the overhead panel support structure in accordance with FIGURE 4. (a) After removal, remove and keep any ducts on the overhead panel support structure necessary to gain access to the BMS 8-39 urethane foam. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 35 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 36 (3) Do PART 1: OVERHEAD PANEL SUPPORT STRUCTURE BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT (4) RC Exempt - Install the kept overhead panel support structure in accordance with FIGURE 5. (a) Before installation, re-install kept ducts on the overhead panel support structure that were removed to gain access to the BMS 8-39 urethane foam. (5) RC Exempt - Close access in accordance with FIGURE 3. (6) RC Exempt - Install the overhead linings. (a) Install the kept left and right overhead lining. Refer to 777 AMM 25-15-06 as an accepted procedure. (b) Install the kept overhead lining aft of the overhead panel support structure. (7) RC Exempt - Supply electrical power to the airplane. Refer to 777 AMM 24-22-00 as an acceptable procedure. (8) RC Exempt - Do the tests in accordance with PART 4: OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES. (9) RC Exempt - Do the tests in accordance with PART 6: ADDITIONAL OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES. (10) RC Exempt - Do the tests in accordance with PART 7: TESTS OF THE EQUIPMENT AFFECTED BY THE REMOVAL OF THE OVERHEAD PANEL SUPPORT STRUCTURE. 6. Put the airplane back to a serviceable condition. Group 1, Configuration 1-2, 4: PART 1: OVERHEAD PANEL SUPPORT STRUCTURE BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT 1. Group 1, Configuration 1: Replace BMS 8-39 urethane foam on the overhead panel support structure in accordance with FIGURE 2. 2. Group 1, Configuration 2, 4: Replace any BMS 8-39 urethane foam found on the overhead panel support structure in accordance with FIGURE 12. Group 1, Configuration 1-2: PART 2: GENERAL VISUAL INSPECTION OF THE DRIPSHIELD 1. Do a General Visual Inspection of the dripshield, above the overhead panel support structure, for BMS 8-39 urethane foam insulation in accordance with FIGURE 7. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 36 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 37 Group 1, Configuration 1-2: PART 3: DRIPSHIELD BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT 1. Replace all BMS 8-39 urethane foam insulation found on the dripshield in accordance with FIGURE 8. Group 1, Configuration 1-2, 4: PART 4: OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES 1. Do a related test of the modules that were removed and installed in the overhead panel support structure. If a test fails, do the corrective action and repeat the test until the test is passed. a. Flight Control Hydraulic Valve Power Module: (1) Do the Hydraulic Shutoff Valves Test. Refer to 777 AMM 27-02-32 as an accepted procedure. b. Auxiliary Power Unit (APU) Maintenance / Electronic Engine Control (EEC) Maintenance Module: (1) Do the APU Bite Test. Refer to 777 AMM 49-11-00 as an accepted procedures. (2) For airplanes with PW 4000 series engines, do the Electronic Engine Control (EEC) System Static Test. Refer to 777 AMM 73-21-00 as an accepted procedure. (3) For airplanes with Trent 800 series engines, do the Electronic Engine Control (EEC) NORM/ALTN Mode Lights Inoperative test. Refer to 777 AMM 73-00-00 as an accepted procedure. (4) For airplanes with GE90 series engines, do the Engine Electronic Engine Control (EEC) Test (MAT Initiated Test). Refer to 777 AMM 71-00-00 as an accepted procedure. c. Ground Test Module: (1) Do the Lower Cargo Compartment Smoke Detection MAT Test. Refer to 777 AMM 26-16-00 as an accepted procedure. d. Left and Right Wiper Modules: (1) Do the Windshield Wiper System - Operation Test. Refer to 777 AMM 30-42-00 as an accepted procedure. e. Pass Signs Module: (1) Do the Cockpit Voice Recorder Microphone Installation Test. Refer to 777 AMM 23-71-04 as an accepted procedure. (2) Do the Flight Compartment Illumination - Operational Test. Refer to 777 AMM 33-11-00 as an accepted procedure. (3) Do the Landing, Runway Turnoff and Taxi Lights - Operational Test. Refer to 777 AMM 33-42-00 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 37 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 38 f. Anti-Ice Module: (1) Do the Wing Anti-Ice - System Test. Refer to 777 AMM 30-11-00 as an accepted procedure. (2) Do the Engine Anti-Ice - System Test. Refer to 777 AMM 30-21-00 as an accepted procedure. g. APU Fire Switch Panel: (1) Do the APU Fire Switch Installation Test. Refer to 777 AMM 26-22-03 as an accepted procedure. Group 1, Configuration 2, 4: PART 5: DETAILED INSPECTION OF THE OVERHEAD PANEL SUPPORT STRUCTURE 1. Do a Detailed Inspection of the overhead panel support structure, for BMS 8-39 urethane foam in accordance with FIGURE 11. PART 6: ADDITIONAL OPERATIONAL TESTS OF THE OVERHEAD PANEL MODULES 1. Do related tests of the additional modules that were removed and installed in the overhead panel support structure. If a test fails, do the corrective action and repeat the test until the test is passed. a. Cargo Temp Select Module: (1) Do the Cargo Temp Select Module Installation Test. Refer to 777 AMM 21-44-09 as an accepted procedure. b. A/C Module: (1) Do the Air Conditioning Module Installation Test. Refer to 777 AMM 21-60-01 as an accepted procedure. c. Emergency Locator Transmitter (ELT) Module: (1) Do the Emergency Locator Transmitter (ELT) System - System Test. Refer to 777 AMM 23-24-00 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. d. Cockpit Voice Recorder Module: (1) Do the Cockpit Voice Recorder System - Operational Test. Refer to 777 AMM 23-71-00 as an accepted procedure. e. Overhead Panel Card File (OPCF): (1) Do the Overhead Panel Card File (OPCF) Installation Test. Refer to 777 AMM 23-93-02 as an accepted procedure. f. Electrical Syst Control Module: Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 38 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 39 (1) Do the AC Generation and Bus Control - Operational Test. Refer to 777 AMM 24-22-00 as an accepted procedure. g. Cargo Fire/Engine Control Module: (1) Do the Cargo Fire/Engine Control Module Installation Test. Refer to 777 AMM 26-22-04 as an accepted procedure. h. Primary Flight Computers/ADIRU Module: (1) Do the Primary Flight Computers/ADIRU Module Operational Test. Refer to 777 AMM 27-02-03 as an accepted procedure. i. Fuel System Module: (1) Do the Fuel System Module Assembly Installation Test. Refer to 777 AMM 28-22-17 as an accepted procedure. j. Hydraulic/Ram Air Turbine Module: (1) Do the Hydraulic/Ram Air Turbine Module - Operational Test. Refer to 777 AMM 29-11-80 as an accepted procedure. k. Window Heat Backup Module: (1) Do the Window Heat Control System - Operational Test. Refer to 777 AMM 30-41-00 as an accepted procedure. l. Window Heat/Emergency Lights Module: (1) Do the Emergency Lights - Functional Test. Refer to 777 AMM 33-51-00 as an accepted procedure. m. Bleed Air/Pressurization Module: (1) Do the Bleed Air/Pressurization Module Installation Test. Refer to 777 AMM 36-11-10 as an accepted procedure. PART 7: TESTS OF THE EQUIPMENT AFFECTED BY THE REMOVAL OF THE OVERHEAD PANEL SUPPORT STRUCTURE 1. Do related tests of the equipment affected by the removal of the overhead panel support structure. If a test fails, do the corrective action and repeat the test until the test is passed. a. Do the Outflow Valve Assembly Installation Test. Refer to 777 AMM 21-31-03 as an accepted procedure. b. Do the Zone Air Temperature Sensor Installation Test. Refer to 777 AMM 21-61-04 as an accepted procedure. c. Do the Autopilot Flight Director Computer Installation Test. Refer to 777 AMM 22-11-01 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 39 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 40 d. Do the Mode Control Panel Installation Test. Refer to 777 AMM 22-11-02 as an accepted procedure. e. Do the Left TMCF - Autothrottle Servo Loop - System Test. Refer to 777 AMM 22-31-00 as an accepted procedure. f. Do the Right TMCF - Autothrottle Servo Loop - System Test. Refer to 777 AMM 22-31-00 as an accepted procedure. g. Do the HF Communication Transceiver Installation Test. Refer to 777 AMM 23-11-05 as an accepted procedure. h. Do the VHF Communication Transceiver Installation Test. Refer to 777 AMM 23-12-01 as an accepted procedure. i. Do the SELCAL Decoder Installation Test. Refer to 777 AMM 23-21-01 as an accepted procedure. j. Do the Audio Management Unit (AMU) Installation Test. Refer to 777 AMM 23-51-04 as an accepted procedure. k. Do the Panel Data Concentrator Unit - System Test. Refer to 777 AMM 23-93-00 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. l. Do the Overhead Panel ARINC 629 System - Operational Test. Refer to 777 AMM 23-93-00 as an accepted procedure. m. Do the Left Overhead Panel Bus Controller (OPBC) Installation test. Refer to 777 AMM 23-93-01 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. n. Do the Right Overhead Panel Bus Controller (OPBC) Installation Test. Refer to 777 AMM 23-93-01 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. o. Do the Signal Interface Unit - Exchange Check. Refer to 777 AMM 24-09-00 as an accepted procedure. p. Do the DC/Standby Power System - Operational Test. Refer to 777 AMM 24-30-00 as an accepted procedure. q. Do the Engine Fire Detection Operational Test. Refer to 777 AMM 26-11-00 as an accepted procedure. r. Do the Engine Fire Switch Test. Refer to 777 AMM 26-21-00 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 40 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 41 s. Do the EDP Depressurization Valve Check. Refer to 777 AMM 26-21-00 as an accepted procedure. t. Do the APU Generator Field Trip Check. Refer to 777 AMM 26-22-00 as an accepted procedure. u. Do the APU Fire Extinguishing Bottle Squib MAT Test. Refer to 777 AMM 26-22-00 as an accepted procedure. v. Do the Lower Cargo Fire Extinguishing Electrical System Test. Refer to 777 AMM 26-23-00 as an accepted procedure. w. Do the Nozzle Distribution Tubing Pressure Test. Refer to 777 AMM 26-23-00 as an accepted procedure. x. Do the Actuator Control Electronics (ACE) Monitor Test. Refer to 777 AMM 27-02-02 as an accepted procedure. y. Do the Engine Fuel Spar Valve - Electrical Control and Indication Test. Refer to 777 AMM 28-22-00 as an accepted procedure. z. Do the Fuel Shutoff Valve Battery - Test. Refer to 777 AMM 28-22-00 as an accepted procedure. aa. Do the Engine-Driven Pump (EDP) Supply Shutoff Valve - System Test. Refer to 777 AMM 29-11-00 as an accepted procedure. ab. Do the Left and Right System Alternating Current Motor Pump (ACMP) Installation Test. Refer to 777 AMM 29-11-01 as an accepted procedure. ac. Do the Center System Alternating Current Motor Pump (ACMP) Installation Test. Refer to 777 AMM 29-11-02 as an accepted procedure. ad. Do the Air-Driven Pump (ADP) Assembly Installation Test. Refer to 777 AMM 29-11-10 as an accepted procedure. ae. Do the Ram Air Turbine (RAT) Manual Deployment System - System Test. Refer to 777 AMM 29-21-00 as an accepted procedure. af. Do the Clock Installation Test. Refer to 777 AMM 31-25-01 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. ag. Do the Warning Electronic System - System Test. Refer to 777 AMM 31-51-00 as an accepted procedure. ah. Do the Warning speaker Installation Test. Refer to 777 AMM 31-51-02 as an accepted procedure. ai. Do the Air/Ground Mode Simulation. Refer to 777 AMM 32-09-00 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 41 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 42 aj. Do the Landing Gear Control System - Functional Test (Airplane on the Ground). Refer to 777 AMM 32-31-00 as an accepted procedure. ak. Do the Landing Gear Control Lever Module Installation Test. Refer to 777 AMM 32-31-01 as an accepted procedure. al. Do the Parking Brake System - Operational Test. Refer to 777 AMM 32-44-00 as an accepted procedure. am. Do the Integral Panel Lights - Operational Test. Refer to 777 AMM 33-13-00 as an accepted procedure. an. Do the Flight Compartment Miscellaneous Lights - Operational Test. Refer to 777 AMM 33-14-00 as an accepted procedure. ao. Do the Master Dim and Test - Operational Test. Refer to 777 AMM 33-16-00 as an accepted procedure. ap. Do the Air Data Standby Instruments - System Test. Refer to 777 AMM 34-13-00 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. aq. Do the Standby Attitude Display Installation Test. Refer to 777 AMM 34-24-01 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. ar. Do the Integrated Standby Flight Display - Operational Test. Refer to 777 AMM 34-24-02 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. as. Do the Weather Radar System - Operational Test. Refer to 777 AMM 34-43-00 as an accepted procedure. at. Do the Traffic Alert and Collision Avoidance System - Operational Test. Refer to 777 AMM 34-45-00 as an accepted procedure. au. Do the Ground Proximity Warning System - Operational Test. Refer to 777 AMM 34-46-00 as an accepted procedure. av. Do the VOR System - Operational Test. Refer to 777 AMM 34-51-00 as an accepted procedure. aw. Do the Air Traffic Control/Mode S Transponder System - Operational Test. Refer to 777 AMM 34-53-00 as an accepted procedure. ax. Do the Distance Measuring Equipment System - Operational Test. Refer to 777 AMM 34-55-00 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 42 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 43 ay. Do the Automatic Direction Finder System - Operational Test. Refer to 777 AMM 34-57-00 as an accepted procedure. az. Do the Passenger Therapeutic Oxygen Operational Test. Refer to 777 AMM 35-22-00 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. ba. Do the ASCPC Installation Test. Refer to 777 AMM 36-11-20 as an accepted procedure. bb. Do the Ground Test Switch Module Installation Test. Refer to 777 AMM 45-10-01 as an accepted procedure. bc. Do the MAT Installation Test. Refer to 777 AMM 45-11-05 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. bd. Do the Display Unit Installation Tests. Refer to 777 AMM 46-11-02 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. be. Do the Terminal Wireless LAN Unit (TWLU) Installation Test. Refer to 777 AMM 46-11-04 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. bf. Do the Wireless WAN Unit - Installation test. Refer to 777 AMM 46-11-07 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. bg. Do the Network File Server Operational Test. Refer to 777 AMM 46-13-01 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. bh. Do the Flight Compartment Security Door Access System Test. Refer to 777 AMM 52-51-00 as an accepted procedure. NOTE: This test may or may not be required and is dependent on airplane delivery configuration. bi. For airplanes with PW 4000 series engines, do the Test No. 20 - MAT Initiated Reverse Thrust Lever Interlock Actuator Test. Refer to 777 AMM 71-00-00 as an accepted procedure. bj. For airplanes with GE90 series engines, do the Test No. 17 - Engine Ignition System Test (MAT Initiated Test). Refer to 777 AMM 71-00-00 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 43 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 44 bk. For airplanes with Trent 800 series engines, do the Test No. 23 - Engine Reverse Thrust Lever Interlock Test (MAT Initiated Test). Refer to 777 AMM 71-00-00 as an accepted procedure. bl. For airplanes with GE90 series engines, do the Fuel Control Switches (in the Fuel Control Module) Test Step D. Refer to 777 AMM 76-11-00 as an accepted procedure. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2: February 28, 2020 44 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 45 (OCR) BOEING SERVICE BULLETIN 777-25-0621 This Figure applies only to: Group 1, Configuration 1. FLIGHT COMPARTMENT (18 OVERHEAD PANEL (TYPICAL) FIGURE 1: FLIGHT COMPARTMENT - OVERHEAD PANEL - OPEN ACCESS (SHEET 1 OF 5) Original Issue: December 10, 2014 Revision 2 February 28, 2020 PROPRIETARY - Copyright © Unpublished Export Controlled ECCN: 9E991 - BOEING 777-25-0621 Work - See page 1 for details. 45 of 88 ### Page 46 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 one airplane. More DataQtyIdentificationNameTaskStep Disengage the quar- ter-turn fasteners to remove the blank panels. 2-BLANK PANELRemove / Keep1 Refer to 777 AMM 30-41-12 as an ac- cepted procedure. 1-WINDOW HEAT BACKUP MODULE Remove / Keep2 Disengage the quar- ter-turn fasteners to pull out the module, then disconnect the electrical connectors at the back of the module. 1-FLT CONTROL HYD VALVE POWER MOD- ULE Remove / Keep Disengage the quar- ter-turn fasteners to remove the blank panels. 1-BLANK PANELRemove / Keep Disengage the quar- ter-turn fasteners to pull out the module, then disconnect the electrical connectors at the back of the module. 1-APU MAINT / EEC MAINT MODULE Remove / Keep3 Disengage the quar- ter-turn fasteners to pull out the module, then disconnect the electrical connectors at the back of the module. 1-GND TEST MODULERemove / Keep Refer to 777 AMM 21-44-09 as an ac- cepted procedure. 1-CARGO TEMP SE- LECT MODULE Remove / Keep Refer to 777 AMM 23-71-02 as an ac- cepted procedure. 1-COCKPIT VOICE RECORDER MODULE Remove / Keep FIGURE 1: FLIGHT COMPARTMENT - OVERHEAD PANEL - OPEN ACCESS (SHEET 2 OF 5) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2 February 28, 2020 46 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 47 More DataQtyIdentificationNameTaskStep Refer to 777 AMM 23-93-02 as an ac- cepted procedure. 2-OVERHEAD PANEL CARD FILE Remove / Keep4 -2-P11 CIRCUIT BREAK- ER PANEL Open5 Disconnect electrical connectors from dis- connect panels AF0201 and AF0202. --ELECTRICAL CON- NECTORS Disconnect Disconnect wiring from terminal block(s). Identify the location of wire to help put them back in the same location during installation. --WIRINGDisconnect Refer to 777 AMM 23-24-03 as an ac- cepted procedure. (a) 1-ELT MODULERemove / Keep6 Disengage the quar- ter-turn fasteners to remove the blank panels. (b) 1-BLANK PANELRemove / Keep7 Refer to 777 AMM 30-41-02 as an ac- cepted procedure. 1-WINDOW HEAT/EMER LIGHTS MODULE Remove / Keep8 Refer to 777 AMM 27-02-03 as an ac- cepted procedure. 1-PRIMARY FLIGHT COMPUTER/ADIRU MODULE Remove / Keep9 Refer to 777 AMM 29-11-80 as an ac- cepted procedure. 1-HYDRAULIC/RAM AIR TURBINE MODULE Remove / Keep10 Refer to 777 AMM 24-22-01 as an ac- cepted procedure. 1-ELECTRICAL SYST CONTROL PANEL Remove / Keep11 FIGURE 1: FLIGHT COMPARTMENT - OVERHEAD PANEL - OPEN ACCESS (SHEET 3 OF 5) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2 February 28, 2020 47 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 48 More DataQtyIdentificationNameTaskStep Disengage the quar- ter-turn fasteners to pull out the module, then disconnect the electrical connectors at the back of the module. 1-L WIPER MODULERemove / Keep12 Disengage the quar- ter-turn fasteners to pull out the module, then disconnect the electrical connectors at the back of the module. 1-R WIPER MODULERemove / Keep Disengage the quar- ter-turn fasteners to pull out the module, then disconnect the electrical connectors at the back of the module. 1-PASS SIGNS MODULERemove / Keep13 Disengage the quar- ter-turn fasteners to pull out the module, then disconnect the electrical connectors at the back of the module. 1-ANTI-ICE MODULERemove / Keep14 Refer to 777 AMM 36-11-10 as an ac- cepted procedure. 1-BLEED AIR/PRESSUR- IZATION MODULE Remove / Keep15 Refer to 777 AMM 28-22-17 as an ac- cepted procedure. 1-FUEL SYST MODULERemove / Keep16 Disengage the quar- ter-turn fasteners to remove the blank panels. 1-BLANK PANELRemove / Keep17 Refer to 777 AMM 21-60-01 as an ac- cepted procedure. 1-A/C MODULERemove / Keep FIGURE 1: FLIGHT COMPARTMENT - OVERHEAD PANEL - OPEN ACCESS (SHEET 4 OF 5) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2 February 28, 2020 48 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 49 More DataQtyIdentificationNameTaskStep Refer to 777 AMM 26-22-04 as an ac- cepted procedure. 1-CARGO FIRE/ENGINE CONTROL MODULE Remove / Keep18 Disengage the quar- ter-turn fasteners to pull out the module, then disconnect the electrical connectors at the back of the panel. 1-APU FIRE SWITCH PANEL Remove / Keep (a) Some airplanes have a blank panel on the upper half and an Emergency Locator Transmitter (ELT) Module on the lower half of this location. Both the blank panel and ELT Module can be removed and kept for these airplanes. (b) Some airplanes have a blank panel on the upper half and a Broadband System Module on the lower half of this location. Both the blank panel and Broadband System Module can be removed and kept for these airplanes. FIGURE 1: FLIGHT COMPARTMENT - OVERHEAD PANEL - OPEN ACCESS (SHEET 5 OF 5) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2 February 28, 2020 49 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 50 This Figure applies only to: Group 1, Configuration 1. FIGURE 2: FLIGHT COMPARTMENT - OVERHEAD PANEL SUPPORT STRUCTURE, BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT (SHEET 1 OF 3) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2 February 28, 2020 50 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 51 (OCR) BOEING SERVICE BULLETIN 777-25-0621 (10 26) A-A 10 26 025 B-B 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 one airplane. Step Task Name Identification Qty More Data 1 Remove INSULATION 233W3307-5 2 2 Remove INSULATION 233W3307-9 1 Remove INSULATION 233W3307-8 1 4 Remove INSULATION 233W3307-7 2 5 Remove INSULATION 233W3307-4 2 6 Remove INSULATION 233W3307-3 2 7 Remove INSULATION 233W3307-6 2 8 Remove INSULATION 233W3307-1 1 9 Remove INSULATION 233W3307-2 1 10 Remove INSULATION 233W3307-11 11| Clean PANEL SUPPORT (a) STRUCTURE 12 Install (New) INSULATION 233W3307-37 1 (b) FIGURE 2: FLIGHT COMPARTMENT - OVERHEAD PANEL SUPPORT STRUCTURE, BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT (SHEET 2 OF 3) Original Issue: December 10, 2014 Revision 2 February 28, 2020 Export Controlled ECCN: 9E991 - BOEING 777-25-0621 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 51 of 88 ### Page 52 More DataQtyIdentificationNameTaskStep (b)1233W3307-38INSULATIONInstall (New)13 (b)1233W3307-41INSULATIONInstall (New)14 (b)1233W3307-30INSULATIONInstall (New)15 (b)1233W3307-39INSULATIONInstall (New)16 (b)1233W3307-40INSULATIONInstall (New)17 (b)1233W3307-31INSULATIONInstall (New)18 (b)1233W3307-32INSULATIONInstall (New)19 (b)1233W3307-35INSULATIONInstall (New)20 (b)1233W3307-36INSULATIONInstall (New)21 (b)1233W3307-33INSULATIONInstall (New)22 (b)1233W3307-34INSULATIONInstall (New)23 (b)1233W3307-27INSULATIONInstall (New)24 (b)1233W3307-28INSULATIONInstall (New)25 (b)1233W3307-29INSULATIONInstall (New)26 (c)--SERVICE BULLETIN NUMBER Apply27 (a) Clean to prepare the surfaces for bonding BMS 8-371 foam insulation. Remove debris after cleaning and do a general clean again. Refer to SOPM 20-30-03 as an accepted procedure. (b) To bond foam insulation on the structure, make sure the side of the foam insulation that has the adhesive faces the structure. To bond foam insulation in position, it is acceptable to use BMS 5-157, Type I, Class 1, Grade A, Form 1, Composition MPVF tape. Align holes in the foam insulation and structure. Cut foam insulation to let it fit around ducts and brackets. (c) Identify the overhead panel support structure with this service bulletin number to show that it is changed. Refer to SOPM 20-50-10 as an accepted procedure. FIGURE 2: FLIGHT COMPARTMENT - OVERHEAD PANEL SUPPORT STRUCTURE, BMS 8-39 URETHANE FOAM INSULATION REPLACEMENT (SHEET 3 OF 3) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2 February 28, 2020 52 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 53 (OCR) BOEING SERVICE BULLETIN 777-25-0621 This Figure applies only to: Group 1, Configuration 1-2, 4. FLIGHT COMPARTMENT 13) OVERHEAD PANEL (TYPICAL) FIGURE 3: FLIGHT COMPARTMENT - OVERHEAD PANEL - CLOSE ACCESS (SHEET 1 OF 5) Original Issue: December 10, 2014 Revision 2 February 28, 2020 PROPRIETARY - Copyright © Unpublished Export Controlled ECCN: 9E991 - BOEING 777-25-0621 Work - See page 1 for details. 53 of 88 ### 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 one airplane. More DataQtyIdentificationNameTaskStep With the blank panel in its position, en- gage the quarter- turn fasteners at all fastener locations. 2-BLANK PANELInstall (Kept)1 Refer to 777 AMM 30-41-12 as an ac- cepted procedure. 1-WINDOW HEAT BACKUP MODULE Install (Kept)2 Connect the electri- cal connectors, then with the module in its position, engage the quarter-turn fas- teners at all fastener locations. 1-FLT CONTROL HYD VALVE POWER MOD- ULE Install (Kept) With the blank panel in its position, en- gage the quarter- turn fasteners at all fastener locations. 1-BLANK PANELInstall (Kept) Connect the electri- cal connectors, then with the module in its position, engage the quarter-turn fas- teners at all fastener locations. 1-APU MAINT / EEC MAINT MODULE Install (Kept)3 Connect the electri- cal connectors, then with the module in its position, engage the quarter-turn fas- teners at all fastener locations. 1-GND TEST MODULEInstall (Kept) Refer to 777 AMM 21-44-09 as an ac- cepted procedure. 1-CARGO TEMP SE- LECT MODULE Install (Kept) Refer to 777 AMM 23-71-02 as an ac- cepted procedure. 1-COCKPIT VOICE RECORDER MODULE Install (Kept) FIGURE 3: FLIGHT COMPARTMENT - OVERHEAD PANEL - CLOSE ACCESS (SHEET 2 OF 5) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2 February 28, 2020 54 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 55 More DataQtyIdentificationNameTaskStep Refer to 777 AMM 23-93-02 as an ac- cepted procedure. 2-OVERHEAD PANEL CARD FILE Install (Kept)4 Connect wiring back in to terminal block(s), in the same locations they were removed from. --WIRINGConnect5 Connect electrical connector back on to disconnect panels AF0201 and AF0202. --ELECTRICAL CON- NECTORS Connect -2-P11 CIRCUIT BREAK- ER PANEL Close Refer to 777 AMM 23-24-03 as an ac- cepted procedure. (a) 1-ELT MODULEInstall (Kept)6 With the blank panel in its position, en- gage the quarter- turn fasteners at all fastener locations. (b) 1-BLANK PANELInstall (Kept)7 Refer to 777 AMM 30-41-02 as an ac- cepted procedure. 1-WINDOW HEAT/EMER LIGHTS MODULE Install (Kept)8 Refer to 777 AMM 27-02-03 as an ac- cepted procedure. 1-PRIMARY FLIGHT COMPUTER/ADIRU MODULE Install (Kept)9 Refer to 777 AMM 29-11-80 as an ac- cepted procedure. 1-HYDRAULIC/RAM AIR TURBINE MODULE Install (Kept)10 Refer to 777 AMM 24-22-01 as an ac- cepted procedure. 1-ELECTRICAL SYST CONTROL PANEL Install (Kept)11 FIGURE 3: FLIGHT COMPARTMENT - OVERHEAD PANEL - CLOSE ACCESS (SHEET 3 OF 5) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2 February 28, 2020 55 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 56 More DataQtyIdentificationNameTaskStep Connect the electri- cal connectors, then with the module in its position, engage the quarter-turn fas- teners at all fastener locations. 1-L WIPER MODULEInstall (Kept)12 Connect the electri- cal connectors, then with the module in its position, engage the quarter-turn fas- teners at all fastener locations. 1-R WIPER MODULEInstall (Kept) Connect the electri- cal connectors, then with the module in its position, engage the quarter-turn fas- teners at all fastener locations. 1-PASS SIGNS MODULEInstall (Kept)13 Connect the electri- cal connectors, then with the module in its position, engage the quarter-turn fas- teners at all fastener locations. 1-ANTI-ICE MODULEInstall (Kept)14 Refer to 777 AMM 36-11-10 as an ac- cepted procedure. 1-BLEED AIR/PRESSUR- IZATION MODULE Install (Kept)15 Refer to 777 AMM 28-22-17 as an ac- cepted procedure. 1-FUEL SYST MODULEInstall (Kept)16 With the blank panel in its position, en- gage the quarter- turn fasteners at all fastener locations. 1-BLANK PANELInstall (Kept)17 Refer to 777 AMM 21-60-01 as an ac- cepted procedure. 1-A/C MODULEInstall (Kept) FIGURE 3: FLIGHT COMPARTMENT - OVERHEAD PANEL - CLOSE ACCESS (SHEET 4 OF 5) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2 February 28, 2020 56 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 57 More DataQtyIdentificationNameTaskStep Refer to 777 AMM 26-22-04 as an ac- cepted procedure. 1-CARGO FIRE/ENGINE CONTROL MODULE Install (Kept)18 Connect the electri- cal connectors, then with the panel in its position, engage the quarter-turn fasten- ers at all fastener lo- cations. 1-APU FIRE SWITCH PANEL Install (Kept) (a) If a blank panel was also removed at this location, install it by positioning the blank panel in its original location then engaging the quarter-turn fasteners at all fastener locations. (b) If a Broadband System Module was also removed at this location, connect the electrical connectors, then with the module in its position, engage the quarter-turn fasteners at all fastener locations. FIGURE 3: FLIGHT COMPARTMENT - OVERHEAD PANEL - CLOSE ACCESS (SHEET 5 OF 5) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2 February 28, 2020 57 of 88 BOEING SERVICE BULLETIN 777-25-0621 ### Page 58 (OCR) BOEING SERVICE BULLETIN 777-25-0621 This Figure applies only to: Group 1, Configuration 1-2, 4. STA 228.44 FWD STA 166.53 2489045 FIGURE 4: FLIGHT COMPARTMENT - OVERHEAD PANEL SUPPORT STRUCTURE - REMOVAL (SHEET 1 OF 3) Original Issue: December 10, 2014 Revision 2 February 28, 2020 Export Controlled ECCN: 9E991 - BOEING 777-25-0621 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 58 of 88 ### Page 59 (OCR) BOEING SERVICE BULLETIN 777-25-0621 (4 4 LOCATIONS (2) 4 LOCATIONS FWD TYPICAL TYPICAL (2 LOCATIONS) (2 LOCATIONS) LBL 1.39 RBL (3) 4 LOCATIONS 1.63 5) 4 LOCATIONS FWD TYPICAL (2 LOCATIONS) A-A 2489053 FIGURE 4: FLIGHT COMPARTMENT - OVERHEAD PANEL SUPPORT STRUCTURE - REMOVAL (SHEET 2 OF 3) Original Issue: December 10, 2014 Revision 2 February 28, 2020 PROPRIETARY - Copyright © Unpublished Export Controlled ECCN: 9E991 - BOEING 777-25-0621 Work - See page 1 for details. 59 of 88 ### 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 each airplane. More DataQtyIdentificationNameTaskStep 2BACN11AG4NUT, SELF-LOCKINGRemove1 2NAS1149D0416HWASHERRemove / Keep 2BACJ40K7A7A22BONDING JUMPERDisconnect 8BACB30LT4-9BOLTRemove / Keep2 8NAS1149F0432PWASHERRemove / Keep 8BACB30LT3-9BOLTRemove / Keep3 8NAS1149F0332PWASHERRemove / Keep 8BACB30LT4-9BOLTRemove / Keep4 8NAS1149F0432PWASHERRemove / Keep 4BACB30LT3-9BOLTRemove / Keep5 4NAS1149F0332PWASHERRemove / Keep Disconnect ducts as necessary. --DUCT ASSEMBLIESDisconnect6 1233W3311-( )OVERHEAD ASSYRemove / Keep FIGURE 4: FLIGHT COMPARTMENT - OVERHEAD PANEL SUPPORT STRUCTURE - REMOVAL (SHEET 3 OF 3) Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: December 10, 2014 777-25-0621Revision 2 February 28, 2020 60 of 88 BOEING SERVICE BULLETIN 777-25-0621 The text continues at https://openairdocs.org/service-documents/boeing/sb-777-25-0621/file/2ba58f20cc9e.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.