### Commercial **Airplanes** 

# 757 Service Bulletin
**Number: 757-28A0079** Original Issue: July 16, 2008 Revision 2: January 11, 2012 ATA System: 2822 **SUBJECT:** FUEL - Engine Fuel Feed System - Fuel Pump Control Ground Fault Interrupter (GFI) Relay Installation Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). 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. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2008 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. Boeing, 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, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery 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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 1 of 50 5.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 2 of 50 **BOEING SERVICE BULLETIN 757-28A0079**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 9 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 A. Effectivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2. Data supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 18 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2. Parts and Materials Supplied by the Operator:. . . . . . . . . . . . . . . . . . . . . . . . 21 3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 4. Parts Removed and Not Replaced:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 22 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 FIGURE 1: P33 PANEL PLATE 'C' - GROUND FAULT INTERRUPTER (GFI) RELAY - REPLACEMENT [Group 1, Configuration 1]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 FIGURE 2: P37 PANEL PLATE 'B' - GROUND FAULT INTERRUPTER (GFI) RELAY - REPLACEMENT [Group 1, Configuration 1]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 FIGURE 3: FUEL BOOST PUMP CONTROL GROUND FAULT INTERRUPTER (GFI) CONTROL RELAY SCHEMATIC REFERENCE [Group 1, Configuration 1]. . . . . . . . . . . . . . . . . . . 46 FIGURE 4: P33 PANEL, PLATE C - GROUND FAULT INTERRUPTER (GFI) RELAY – ELECTRICAL BONDING RESISTANCE MEASUREMENTS . . . . . . . . . . . . . . . . . . . . . . . . 47 FIGURE 5: P37 PANEL, PLATE B - GROUND FAULT INTERRUPTER (GFI) RELAY – ELECTRICAL BONDING RESISTANCE MEASUREMENTS . . . . . . . . . . . . . . . . . . . . . . . . 49

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 3 of 50 **BOEING SERVICE BULLETIN 757-28A0079**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 4 of 50 **BOEING SERVICE BULLETIN 757-28A0079**

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### Commercial **Airplanes** 

# 757 Service Bulletin **Revision Transmittal Sheet Number: 757-28A0079**  Original Issue: July 16, 2008 Revision 2: January 11, 2012 ATA System: 2822 **SUBJECT:** FUEL - Engine Fuel Feed System - Fuel Pump Control Ground Fault Interrupter (GFI) Relay Installation This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** No more work is necessary on the airplane(s) changed in accordance with Revision 1 of this service bulletin. But, more work is necessary on airplanes changed in accordance with the Original Issue of this service bulletin, thus Group 1, Configuration 2 is added to the service bulletin effectivity, for those airplanes. Group 1, Configuration 2 gives instructions to do a General Visual Inspection (GVI) of the Ground Fault Interrupter (GFI) relay installation screw grip lengths, and replace them if necessary, then measure the electrical bonding resistance of the GFI relay and repair the bond if necessary. **REASON FOR REVISION** This revision is sent to correct formatting and typographical errors in the Work Instructions and Figures that were introduced at Revision 1 of this service bulletin. Group 1, Configuration 2 is added to the service bulletin effectivity, and applied to sections, as applicable, to better identify the more work necessary for airplanes changed in accordance with the Original Issue of this service bulletin. The Compliance statement is changed to refer to the original issue date of this service bulletin and future FAA AD statement added. Step table footnotes in Figures 1 and 2 are updated to better describe the re-identification of the P37 Panel. Also, the procedure for screw inspection and replacement is improved. Figures 4 and 5 are updated to give an improved procedure for electrical bonding resistance measurements. The service bulletin format standards have been updated where applicable. These sections are changed: 1. Summary, Reason: More data on Airworthiness Limitation, 28-AWL-21, added. 2. Summary, Action: Applicability and actions for Group 1, Configuration 2 added. 3. Summary, Compliance: Changed to refer to the original issue date of this service bulletin and added future FAA AD release statement. 4. Summary, Manpower: Applicability and Manpower table for Group 1, Configuration 2 added. 5. Summary, Illustration: Applicability and actions for Group 1, Configuration 2 added. 6. Paragraph 1.A., Effectivity: Configurations added to group configuration table. 7. Paragraph 1.C., Reason: Detail regarding Airworthiness Limitation, 28-AWL-21, added.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 5 of 508. Paragraph 1.D., Description: Applicability and actions for Group 1, Configuration 2 added. 9. Paragraph 1.E., Compliance: Changed to refer to the original issue date of this service bulletin and added future FAA AD release statement. 10. Paragraph 1.G., Manpower: Applicability and Manpower table for Group 1, Configuration 2 added. 11. Paragraph 1.H., Weight and Balance Changes: Applicability added. 12. Paragraph 1.H., Electrical Load Data: Applicability added. 13. Paragraph 1.J.1., Existing Data: References updated. 14. Paragraph 1.K., Publications Affected: Added Aircraft Maintenance Manual and Equipment List. Corrected Maintenance Planning Data reference, to Section 9. 15. Paragraph 2.C.2., Parts and Materials Supplied by the Operator: Applicability and parts table for Group 1, Configuration 2 added. Footnote changed. 16. Paragraph 2.C.4., Parts Removed and Not Replaced: Table deleted - not applicable. 17. Paragraph 3.A., General Information: General notes updated. 18. Paragraph 3.B., Work Instructions, Part 1: Applicability and step 5 added. Order changed for Steps 11 and 12. Formatting errors corrected. 19. Paragraph 3.B., Work Instructions, Part 2: Applicability and steps 1 thru 4 added. Added replacement screw, P/N NAS1801-08-7 (or BACS12HN08-7). Corrected steps 5 and 6 and added notes for SRM data. 20. Figure 1: Applicability added. Updated part numbers and added optional replacement screw, P/N BACS12HN08-7. Corrected steps 1 thru 3 and footnotes (a) and (b). Added footnotes (c) and (d). 21. Figure 2: Applicability added. Updated part numbers and added optional replacement screws, P/N BACS12CK08-7 or BACS12HN08-7. Corrected steps 1 thru 3 and footnotes (a) and (b). Added footnotes (c) and (d). 22. Figure 3: Applicability added. 23. Figure 4: Footnotes updated and illustration corrected. 24. Figure 5: Footnotes updated and illustration corrected. The data given in Information Notice 757-28A0079 R01 IN 02 and 757-28A0079 R01 IN 03 is included in this revision. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 6 of 50 **BOEING SERVICE BULLETIN 757-28A0079 REVISION HISTORY**  July 16, 2008 Original Issue: August 24, 2010 Revision 1: January 11, 2012 Revision 2:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 7 of 50 **BOEING SERVICE BULLETIN 757-28A0079**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 8 of 50 **BOEING SERVICE BULLETIN 757-28A0079**

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### Commercial **Airplanes** 

# 757 Service Bulletin **Summary Number: 757-28A0079**  Original Issue: July 16, 2008 Revision 2: January 11, 2012 ATA System: 2822 **SUBJECT:** FUEL - Engine Fuel Feed System - Fuel Pump Control Ground Fault Interrupter (GFI) Relay Installation **CONCURRENT REQUIREMENTS**
None. **BACKGROUND** This service bulletin gives instructions to replace the power control relays for the fuel boost pumps and override pumps. The relays are located in the P33 and P37 equipment panels in the main equipment center. The new relays include a Ground Fault Interrupt (GFI) feature. The GFI feature will protect the fuel pumps from damage caused by electrical arcing. Electrical arcing could create a possible source of ignition of flammable fuel vapors in the fuel tanks. Ignition of flammable fuel vapors could cause a fire or explosion which could put the airplane in an unsafe condition. This service bulletin is the result of the safety assessments conducted by Boeing under SFAR 88, "Fuel Tank System Fault Tolerance Evaluation Requirements". The Airworthiness Limitation (AWL) 28-AWL-21, "Boost Pump Ground Fault Interrupter (GFI)" listed in Maintenance Planning Data (MPD) Document, D622N001 - 757 MPD Section 9 , Airworthiness Limitations (AWL's) and Certification Maintenance Requirements (CMR's) is related to this service bulletin. The Airworthiness Limitation (AWL) 28-AWL-21 requires operators to verify every year the continued functionality of the GFI circuit. The related 757-200 airplane service bulletin number is 757-28A0078. **ACTION (PRR 55000-10RS) Group 1, Configuration 1:**  Get access to the main equipment center. On the P33 and P37 panels, replace the six GFI relays and make sure the grip lengths of the installation screws are correct. Replace the installation screws if too short. Measure the electrical bonding resistance between the GFI relays and the P33 Panel, Plate C, and P37 Panel, Plate B, as applicable. Do an operational test of the fuel boost pumps. **Group 1, Configuration 2:** Get access to the main equipment center. On the P33 and P37 panels, do a General Visual Inspection of the GFI relay installation screws, for correct grip length. Replace the screws if too short. Measure the electrical bonding resistance between the GFI relays and the P33 Panel, Plate C, and P37 Panel, Plate B, as applicable, and repair the bond if necessary.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 9 of 50**EFFECTIVITY** 757-300 Airplane(s). Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplane(s). **COMPLIANCE** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Boeing recommends that operators incorporate the changes shown in this service bulletin within 60 months after the original issue date of this service bulletin. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the configuration changes given in this service bulletin. **MANPOWER Group 1, Configuration 1:**  **Elapsed Hours Total Task Hours**  6.0 8.0 **Group 1, Configuration 2: Elapsed Hours**  **Total Task Hours** 3.0 3.0
**MATERIAL INFORMATION** Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 10 of 50 **BOEING SERVICE BULLETIN 757-28A0079**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 11 of 50 **BOEING SERVICE BULLETIN 757-28A0079**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 12 of 50 **BOEING SERVICE BULLETIN 757-28A0079**

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### Commercial **Airplanes** 

# 757 Service Bulletin
**Number: 757-28A0079** Original Issue: July 16, 2008 Revision 2: January 11, 2012 ATA System: 2822 **SUBJECT:** FUEL - Engine Fuel Feed System - Fuel Pump Control Ground Fault Interrupter (GFI) Relay Installation
**1. PLANNING INFORMATION A. Effectivity**  1. Airplanes Refer to Service Bulletin Index D624N001, Part 3, for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. Refer to PRR55000-10RS for data about this change.
**DESCRIPTION CONFIGURATION**  **GROUP** 757-300 Airplanes

- 1 Airplanes which have not accomplished the Original Issue or Revision 1 of this Service Bulletin. 1
Airplanes which have accomplished the Original Issue of this Service Bulletin. 2

Airplane Models:
757-300 **Group Variable Number**  1 NL001 - NL002 1 NL006 - NL017 1 NL101 - NL109 1 NL141 1 NL601 - NL616 1 NU701 - NU705

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 13 of 50**Group Variable Number**  1 NU721 - NU728 1 NU731 - NU732 2. Spares Affected Examine your spares supply for the parts or components identified in Paragraph 2.C., Parts Necessary for Each Airplane. If any parts or components are found, refer to Paragraph 2.C. for the recommended use. **B. Concurrent Requirements**
None. **C. Reason** This service bulletin gives instructions to replace the power control relays for the fuel boost pumps and override pumps. The relays are located in the P33 and P37 equipment panels in the main equipment center. The new relays include a Ground Fault Interrupt (GFI) feature. The GFI feature will protect the fuel pumps from damage caused by electrical arcing. Electrical arcing could create a possible source of ignition of flammable fuel vapors in the fuel tanks. Ignition of flammable fuel vapors could cause a fire or explosion which could put the airplane in an unsafe condition. This service bulletin is the result of the safety assessments conducted by Boeing under SFAR 88, "Fuel Tank System Fault Tolerance Evaluation Requirements". The Airworthiness Limitation (AWL) 28-AWL-21, "Boost Pump Ground Fault Interrupter (GFI)" listed in Maintenance Planning Data (MPD) Document, D622N001 - 757 MPD Section 9 , Airworthiness Limitations (AWL's) and Certification Maintenance Requirements (CMR's) is related to this service bulletin. The Airworthiness Limitation (AWL) 28-AWL-21 requires operators to verify every year the continued functionality of the GFI circuit. The related 757-200 airplane service bulletin number is 757-28A0078. Revision 01 was sent to tell operators that the screws used to the install the relays in FIGURE 1 have been changed from NAS1801-08-5 to NAS1801-08-7. Substitution information for the installation screws was added to FIGURE 2. This revision also provides a new electrical bonding resistance check of the GFI relays replaced on both the P33 and P37 Panels. These sections were changed: 1. Revised Paragraph 1.C., Reason to add the reason for Revision 01. 2. Revised Paragraph 1.D., Description to add 'More work is necessary' note and the maintenance zones table. 3. Revised Paragraph 1.J., References to add 757-300 SRM 51-40-02, 757-300 SRM 51-40-03, and added a table for installation drawings used... in Paragraph 1.J.3. 4. Revised Paragraph 1.K., Publications Affected to add the Damage Tolerance Inspection note.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 14 of 50 **BOEING SERVICE BULLETIN 757-28A0079**5. Revised Paragraph 3.A., General Information to add general notes for fastener installation and substitution. 6. Revised Paragraph 3.B., Work Instructions to add the existing work instructions to a new PART 1 and new paragraphs 3.B.PART 1.7 and 8. Also added new PART 2. 7. Revised FIGURE 1 step table to add the correct the fasteners for the relay installation. New sub-steps were added. 8. Revised FIGURE 2 step table to add optional fastener information. New sub-steps were added. 9. Added FIGURE 4 to show where to take electrical bonding resistance check readings for the GFI relays K187, K10011, K190, on the P33 Panel, Plate C. 10. Added FIGURE 5 to show where to take electrical bonding resistance check readings for the GFI relays K188, K189, K10012, on the P37 Panel, Plate B. The data given in Information Notice 757-28A0079 IN 01 is included in this revision. Revision 2 is sent to correct formatting and typographical errors in the Work Instructions and Figures that were introduced at Revision 1 of this service bulletin. Group 1, Configuration 2 is added to the service bulletin effectivity, and applied to sections, as applicable, to better identify the more work necessary for airplanes changed in accordance with the Original Issue of this service bulletin. The Compliance statement is changed to refer to the original issue date of this service bulletin and future FAA AD statement added. Step table footnotes in Figures 1 and 2 are updated to better describe the re-identification of the P37 Panel. Also, the procedure for screw inspection and replacement is improved. Figures 4 and 5 are updated to give an improved procedure for electrical bonding resistance measurements. The service bulletin format standards have been updated where applicable. The data given in Information Notice 757-28A0079 R01 IN 02 and 757-28A0079 R01 IN 03 is included in this revision. **D. Description Group 1, Configuration 1:**  Get access to the main equipment center. On the P33 and P37 panels, replace the six GFI relays and make sure the grip lengths of the installation screws are correct. Replace the installation screws if too short. Measure the electrical bonding resistance between the GFI relays and the P33 Panel, Plate C, and P37 Panel, Plate B, as applicable. Do an operational test of the fuel boost pumps. **Group 1, Configuration 2:** Get access to the main equipment center. On the P33 and P37 panels, do a General Visual Inspection of the GFI relay installation screws, for correct grip length. Replace the screws if too short. Measure the electrical bonding resistance between the GFI relays and the P33 Panel, Plate C, and P37 Panel, Plate B, as applicable, and repair the bond if necessary. Revision 1: More work is necessary on airplanes changed in accordance with the original issue of this service bulletin. Do a General Visual Inspection of the installation screws for the GFI relays K187, K10011, K190, on Plate C of the P33 Panel and the installation screws for the GFI relays K188, K189, K10012, on Plate B of the P37 Panel to ensure the necessary grip length screw was used. More work is necessary to measure the electrical bonding resistance between the GFI Relays and the P33 Panel, Plate C and measure the electrical bonding resistance between the GFI Relays and the P37 Panel, Plate B.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 15 of 50 **BOEING SERVICE BULLETIN 757-28A0079**Revision 2 - No more work is necessary on the airplane(s) changed in accordance with Revision 1 of this service bulletin. But, more work is necessary on airplanes changed in accordance with the Original Issue of this service bulletin, thus Group 1, Configuration 2 is added to the service bulletin effectivity, for those airplanes. Group 1, Configuration 2 gives instructions to do a General Visual Inspection (GVI) of the Ground Fault Interrupter (GFI) relay installation screw grip lengths, and replace them if necessary, then measure the electrical bonding resistance of the GFI relay and repair the bond if necessary. The work in this service bulletin is done in the maintenance zone(s) given below.
**Affected Maintenance Zones Zone**  **Model** 119 757-300 **E. Compliance** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Boeing recommends that operators incorporate the changes shown in this service bulletin within 60 months after the original issue date of this service bulletin. **F. Approval** This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. **G. Manpower** The table below shows an estimate of the task-hours necessary to do this change for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator 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 examine the work — Time to cure the materials — Time to make the parts — Time to find the tools.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 16 of 50 **BOEING SERVICE BULLETIN 757-28A0079 Group 1, Configuration 1:**  **Elapsed Hours Task-Hours**  **Number of Per- sons**  **Task**

0.75 0.75 1 Open Access 2.5 2.5 1 Change 0.75 0.75 1 Close Access 2.0 4.0 2 Test 6.0 8.0 TOTAL FOR EACH AIRPLANE **Group 1, Configuration 2: Elapsed Hours**  **Task-Hours Number of Per-**  **sons Task** 

0.75 0.75 1 Open Access 1.5 1.5 1 Inspect 0.75 0.75 1 Close Access 3.0 3.0 TOTAL FOR EACH AIRPLANE **H. Weight and Balance Changes Group 1, Configuration 1:**  **Change in Moment (Pound-Inches)**  **Change in Weight (Pounds)**  **Airplane**

+ 380.0 + 1.6 757-300 **Group 1, Configuration 2:** None. **I. Electrical Load Data** 1. Direct Current (DC) Loads
None. 2. Alternating Current (AC) Loads

**Group 1, Configuration 1:**
**Bus Phase**  **Volt-Ampere- Reactive**  **(VARs) Watts**  **Airplanes**

115V AC BUS LEFT - SECTION 1 C 0.52 - 0.53 757-300

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 17 of 50 **BOEING SERVICE BULLETIN 757-28A0079 Group 1, Configuration 1:** 
**Bus Phase**  **Volt-Ampere- Reactive**  **(VARs) Watts**  **Airplanes**

115V AC BUS LEFT - SECTION 3 C 1.04 - 1.06 757-300 115V RIGHT AC TRANSFER BUS C 0.52 - 0.53 757-300 115V AC GROUND SERVICE BUS C 0.52 - 0.53 757-300 115V AC BUS RIGHT - SECTION 3 C 0.52 - 0.53 757-300 **Group 1, Configuration 2:** None. 3. Type Continuous **J. References** 1. Existing Data: a. Engineering Change Memo PRR 55000-10RS. b. Boeing Service Bulletin 757-28A0078. c. Service Bulletin Index D624N001. d. Standard Overhaul Practices Manual (SOPM) 20-11-03, 20-50-01, 20-50-10. e. Standard Wiring Practices Manual (SWPM) 20-10-11, 20-10-12, 20-10-19, 20-20-00. f. 757 Aircraft Maintenance Manual (AMM) 06-44-00, 24-22-00, 24-31-01, 24-31-03, 28-22-03, 28-22-15, 28-26-00. g. 757 Maintenance Planning Data, D622N001, Section 9, Airworthiness Limitations (AWLs)and Certification Maintenance Requirements (CMRs). h. 757-300 Structural Repair Manual (SRM) 51-40-02, 51-40-03, 51-40-04. 2. Data supplied with this Service Bulletin:
None. 3. Installation Drawings Used in the Preparation of this Service Bulletin:
**Title Drawing Number**  SHIELD INSTL-MISC ELEC EQUIP P33 284N1325 SHIELD INSTL-MISC ELEC EQUIP P37 284N1526

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 18 of 50 **BOEING SERVICE BULLETIN 757-28A0079 Title**  **Drawing Number** SHIELD ASSY-MISC ELEC EQUIP P33 284N1318 PANEL ASSY-RIGHT MISC. RELAY, P37 284N1127 These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators. **K. Publications Affected** 1. Publications: **Chapter-Section Publication**  28-22 757 Aircraft Maintenance Manual 28-22 757 Wiring Diagram Manual 28-22 757 Fault Isolation Manual 28-22 757 Illustrated Parts Catalog 28-22 757 System Schematic Manual N/A Equipment List Section 9: Airworthiness Limitations(AWLs) and Certification Maintenance Requirements (CMRs). 757 Maintenance Planning Data

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. **L. Interchangeability and Intermixability of Parts** Refer to Paragraph 2.C., Parts Necessary for Each Airplane, for interchangeability and intermixability information.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 19 of 50 **BOEING SERVICE BULLETIN 757-28A0079**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 20 of 50 **BOEING SERVICE BULLETIN 757-28A0079**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  The operator can supply the parts and materials shown in Paragraph 2.C., Parts Necessary for Each Airplane and Paragraph 2.D., Parts Necessary to Change Spares. As an alternative, operators can purchase the parts from Boeing Spares. This service bulletin does not show the Boeing price and supply data. **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:
None. 2. Parts and Materials Supplied by the Operator: **Group 1, Configuration 1:**
**Notes Existing Part Number**  **Name QTY**  **Part Number / Specification**  (a) MS27418-2A RELAY 6 9324G-10676 (b) N/A SCREW 24 NAS1801-08-7 (BACS12HN08-7 optional) (a) Leach International North America (V58657) 6900 Orangethorpe Avenue, P.O. Box 5032, Buena Park, CA 90622-5032 Phone: (714) 739-0770 Fax: (714) 670-1145. (b) Replacement screws, of correct grip length, as necessary. **Group 1, Configuration 2:**
**Notes Existing Part Number**  **Name QTY**  **Part Number / Specification**  (a) N/A SCREW

- NAS1801-08-7 (BACS12HN08-7 optional) (a) Replacement screws, of correct grip length, as necessary.
3. Parts Modified and Reidentified: None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 21 of 50 **BOEING SERVICE BULLETIN 757-28A0079**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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 22 of 50 **BOEING SERVICE BULLETIN 757-28A0079 3. ACCOMPLISHMENT INSTRUCTIONS**  **A. GENERAL INFORMATION CAUTION:**  KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:** 1. The instructions identified in Paragraph 3.B., Work Instructions and the Figure(s) give the recommended sequence of steps. The sequence of steps to do this service bulletin can be changed. 2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 3. Obey all of the warnings and cautions given in the specified manual sections. 4. Use the approved fastener and process 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. If the length of any fastener specified in this service bulletin does not meet installation standards given in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards given in SRM Chapter 51 may be used. In addition, washers may be installed for fastener grip length in accordance with SRM Chapter 51. 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. 8. 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. 9. 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. 10. This service bulletin includes functional test procedures for the systems changed by this service bulletin. More functional tests can possibly be necessary in accordance with standard maintenance practices because of interruption to other airplane systems.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 23 of 50 **BOEING SERVICE BULLETIN 757-28A0079 B. WORK INSTRUCTIONS**  **Group 1, Configuration 1: PART 1 -** **GFI RELAY REPLACEMENT AND FUEL BOOST PUMP CONTROL RELAY OPERATIONAL TEST** **- FOR AIRPLANES THAT HAVE NOT INCORPORATED THE ORIGINAL ISSUE OR REVISION**  **1 OF THIS SERVICE BULLETIN.**  **WARNING:** DO THE DEACTIVATION PROCEDURE FOR THE SPOILERS OR MOVE ALL PERSONS AND EQUIPMENT AWAY FROM THE SPOILERS. THE SPOILERS CAN RETRACT QUICKLY AND CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT. **WARNING:** IF THE EXTERNAL POWER SUPPLY HAS AN EARTH GROUNDED NEUTRAL, THERE MUST NOT BE AN OPEN OR FLOATING GROUND IN THE NEUTRAL CIRCUIT WIRING OF THE SUPPLY OR THE AIRPLANE. IF AN OPEN OR FLOATING GROUND IS PRESENT, THE AIRPLANE CAN BE PUT AT AN ELECTRICAL POTENTIAL ABOVE EARTH GROUND. THIS ELECTRICAL POTENTIAL CAN RESULT IN ELECTRIC SHOCK WITH POSSIBLE SEVERE INJURY TO PERSONNEL WHO TOUCH THE AIRPLANE **WARNING:** REMOVE THE ELECTRICAL POWER FROM THE EXTERNAL POWER CABLE BEFORE YOU CONNECT THE CABLE TO THE AIRPLANE. INJURY TO PERSONS CAN BE CAUSED BY AN ELECTRICAL SHOCK. 1. Remove electrical power from the airplane. Refer to 757 AMM 24-22-00 as an accepted procedure. 2. Disconnect the battery connectors from the batteries. Refer to 757 AMM 24-31-01 (for the main battery) and 757 AMM 24-31-03 (for the Auxiliary Power Unit battery) as accepted procedures. 3. Put each of the following fuel pump and valve control switches in the position shown below:
**Position Location**  **Switch** OFF P5 Panel L FWD PUMP OFF P5 Panel LEFT C PUMP OFF P5 Panel R AFT PUMP OFF P5 Panel RIGHT C PUMP OFF P5 Panel R FWD PUMP OFF P5 Panel L AFT PUMP CUTOFF P10 Stand L FUEL CONTROL CUTOFF P10 Stand R FUEL CONTROL NORMAL P8 Stand L FIRE HANDLE NORMAL P8 Stand R FIRE HANDLE NORMAL P8 Stand APU FIRE SWITCH 4. Open these circuit breakers. Attach a DO-NOT-CLOSE tag to each opened circuit breaker:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 24 of 50 **BOEING SERVICE BULLETIN 757-28A0079 Circuit Breaker**  **Name Panel / Location**  C369 L FUEL OVRD PUMP P6-3 / F14 C370 R FUEL OVRD PUMP P6-4 / F20 C366 L AFT FUEL BOOST PUMP P6-3 / H14 C368 R FWD FUEL BOOST PUMP P6-3 / H17 C371 R AFT FUEL BOOST PUMP P6-4 / H20 C372 L FWD FUEL BOOST PUMP P6-4 / H23 5. Get access to the Main equipment Center (MEC). 6. Replace the three GFI relays in the P33 panel, for the fuel boost pumps, in accordance with FIGURE 1 and FIGURE 3. 7. Replace the three GFI relays in the P37 panel, for the fuel boost pumps, in accordance with FIGURE 2 and FIGURE 3. 8. Measure the electrical bonding resistance between each GFI Relay K187, K10011, K190 and the P33 Panel, Plate C, in accordance with FIGURE 4. 9. Measure the electrical bonding resistance between each GFI Relay K188, K189, K10012 and the P37 Panel, Plate B, in accordance with FIGURE 5. 10. Remove the DO-NOT-CLOSE tags and close these circuit breakers:
**Circuit Breaker Name**  **Panel / Location** C369 L FUEL OVRD PUMP P6-3 / F14 C370 R FUEL OVRD PUMP P6-4 / F20 C366 L AFT FUEL BOOST PUMP P6-3 / H14 C368 R FWD FUEL BOOST PUMP P6-3 / H17 C371 R AFT FUEL BOOST PUMP P6-4 / H20 C372 L FWD FUEL BOOST PUMP P6-4 / H23 11. Connect the battery connectors to the batteries. Refer to 757 AMM 24-31-01 (for the main battery) and 757 AMM 24-31-03 (for the auxiliary power unit (APU) battery) as accepted procedures. 12. Restore electrical power to the airplane. Refer to 757 AMM 24-22-00 as an accepted procedure. 13. Prepare to do the following operational test of the GFI relay installation:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 25 of 50 **BOEING SERVICE BULLETIN 757-28A0079**a. Make sure that the center fuel tank contains a fuel quantity between 7,000 and 15,000 pounds (3,200 and 6,800 kilograms). b. Make sure that the left main fuel tank contains a fuel quantity between 3,000 and 5,000 pounds (1,400 and 2,300 kilograms). c. Make sure that the right main fuel tank contains a fuel quantity between 3,000 and 5,000 pounds (1,400 and 2,300 kilograms). d. Make sure that the valves that follow are closed. Refer to 757 AMM 28-22-03 as an accepted procedure.
**Location Valve**  Rear Spar at LH IRSS 264.50 Engine Fuel Shutoff Valve (Spar Valve) for the No. 1 Tank Rear Spar at RH IRSS 264.50 Engine Fuel Shutoff Valve (Spar Valve) for the No. 2 Tank Rear Spar at LBL 13.70, WL 184.35 The Crossfeed Valve(s) LH and RH Rear Spars at IRSS 206.75 The Defuel Valve
**WARNING:** DO NOT OPERATE A FUEL PUMP IF THE LOW PRESSURE LIGHT COMES ON AND STAYS ON. FUEL VAPORS IN THE TANK MAY IGNITE AND CAUSE A FIRE OR EXPLOSION. e. To operate any of the fuel pumps, personnel must be in the flight compartment to monitor the fuel quantity and the low pressure indication in the fuel tank. Immediately set the applicable fuel pump switch to OFF if the PRESS light comes on and stays on. f. Open the fueling station door, 621GB. Refer to 757 AMM 06-44-00 as an accepted procedure. g. Do a test of the left aft fuel boost pump control relay (K187) located in the P33 panel as shown below. **Left Aft Fuel Boost Pump Control Relay - Operation** (1) Push the left aft fuel boost pump (L AFT PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (2) Listen and make sure the left aft fuel boost pump operates. (3) Make sure the left aft fuel boost pump PRESS light on the P5-2 fuel management control panel goes off.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 26 of 50 **BOEING SERVICE BULLETIN 757-28A0079 CAUTION:**  IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE LEFT AFT FUEL BOOST PUMP (L AFT PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push the left aft fuel boost pump (L AFT PUMP) switch-light to the OFF position. (5) Listen and make sure the left aft fuel boost pump does not operate. (6) Make sure the left aft fuel boost pump PRESS light comes on. **Left Aft Fuel Boost Pump - Ground Fault Interruption Function** (1) Push the left aft fuel boost pump (L AFT PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (2) Listen and make sure the left aft fuel boost pump operates. (3) Make sure the left aft fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE LEFT AFT FUEL BOOST PUMP (L AFT PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push the left aft fuel boost pump GFI control relay K187 TEST button. (5) Listen and make sure the left aft fuel boost pump does not operate. (6) Make sure the left aft fuel boost pump PRESS light comes on. (7) Make sure the left aft fuel boost pump GFI control relay K187 RESET button has moved up so that a white band is visible. **NOTE:** The RESET button located at the top edge of GFI relay (K187) moves up, to expose a narrow, white band when the GFI circuit turns off the K187 relay due to a ground fault, or results when you push the TEST button located on the top surface of the K187 relay. (8) Push the left aft fuel boost pump (L AFT PUMP) switch-light to the OFF position. (9) Push in the left aft fuel boost pump GFI control relay K187 RESET button. Make sure the RESET button does not move up and the white band is not visible. (10) Push the left aft fuel boost pump (L AFT PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (11) Listen and make sure the left aft fuel boost pump operates. (12) Make sure the left aft fuel boost pump PRESS light on the P5-2 fuel management control panel goes off.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 27 of 50 **BOEING SERVICE BULLETIN 757-28A0079 CAUTION:**  IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE LEFT AFT FUEL BOOST PUMP (L AFT PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (13) Push the left aft fuel boost pump (L AFT PUMP) switch-light to the OFF position. (14) Listen and make sure the left aft fuel boost pump does not operate. (15) Make sure the left aft fuel boost pump PRESS light on the P5-2 fuel management control panel comes on. h. Do a test of the left forward fuel boost pump control relay (K188) located in the P37 panel as shown below. **Left Forward Fuel Boost Pump Control Relay - Operation** (1) Push the left forward fuel boost pump (L FWD PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (2) Listen and make sure the left forward fuel boost pump operates. (3) Make sure the left forward fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE LEFT FORWARD FUEL BOOST PUMP (L FWD PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push the left forward fuel boost pump (L FWD PUMP) switch-light to the OFF position. (5) Listen and make sure the left forward fuel boost pump does not operate. (6) Make sure the left forward fuel boost pump PRESS light comes on. **Left Forward Fuel Boost Pump - Ground Fault Interruption Function** (1) Push the left forward fuel boost pump (L FWD PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (2) Listen and make sure the left forward fuel boost pump operates. (3) Make sure the left forward fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE LEFT FORWARD FUEL BOOST PUMP (L FWD PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push in the left forward fuel boost pump GFI control relay K188 TEST button.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 28 of 50 **BOEING SERVICE BULLETIN 757-28A0079**(5) Listen and make sure the left forward fuel boost pump does not operate. (6) Make sure the left forward fuel boost pump PRESS light comes on. (7) Make sure the left forward fuel boost pump GFI control relay K188 RESET button has moved up so that a white band is visible. **NOTE:** The RESET button located at the top edge of GFI relay (K188) moves up, to expose a narrow, white band when the GFI circuit turns off the K188 relay due to a ground fault, or results when you push the TEST button located on the top surface of the K188 relay. (8) Push the left forward fuel boost pump (L FWD PUMP) switch-light to the OFF position. (9) Push in the left forward fuel boost pump GFI control relay K188 RESET button. Make sure the RESET button does not move up and the white band is not visible. (10) Push the left forward fuel boost pump (L FWD PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (11) Listen and make sure the left forward fuel boost pump operates. (12) Make sure the left forward fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE LEFT FORWARD FUEL BOOST PUMP (L FWD PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (13) Push the left forward fuel boost pump (L FWD PUMP) switch-light to the OFF position. (14) Listen and make sure the left forward fuel boost pump does not operate. (15) Make sure the left forward fuel boost pump PRESS light on the P5-2 fuel management control panel comes on. i. Do a test of the left override fuel boost pump control relay (K10011) located in the P33 panel as shown below. **Left Override Fuel Boost Pump Control Relay - Operation** (1) Push the left override fuel boost pump (LEFT C PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (2) Listen and make sure the left override fuel boost pump operates. (3) Make sure the left override fuel boost pump PRESS light on the P5-2 fuel management control panel goes off.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 29 of 50 **BOEING SERVICE BULLETIN 757-28A0079 NOTE:**  Low pressure (PRESS) light comes on momentarily after the pump switch is set to the ON position. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE LEFT OVERRIDE FUEL BOOST PUMP (LEFT C PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push the left override fuel boost pump (LEFT C PUMP) switch-light to the OFF position. (5) Listen and make sure the left override fuel boost pump does not operate. **NOTE:** The left override fuel boost pump PRESS light stays off when the pump switch is turned to OFF. **Left Override Fuel Boost Pump - Ground Fault Interruption Function** (1) Push the left override fuel boost pump (LEFT C PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (2) Listen and make sure the left override fuel boost pump operates. (3) Make sure the left override fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **NOTE:** Low pressure (PRESS) light comes on momentarily after the pump switch is set to the ON position. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE LEFT OVERRIDE FUEL BOOST PUMP (LEFT C PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push the left override fuel boost pump GFI control relay K10011 TEST button. (5) Listen and make sure the left override fuel boost pump does not operate. (6) Make sure the left override fuel boost pump PRESS light comes on. (7) Make sure the left override fuel boost pump GFI control relay K10011 RESET button has moved up so that a white band is visible. **NOTE:** The RESET button located at the top edge of GFI relay (K10011) moves up, to expose a narrow, white band when the GFI circuit turns off the K10011 relay due to a ground fault, or results when you push the TEST button located on the top surface of the K10011 relay. (8) Push the left override fuel boost pump (LEFT C PUMP) switch-light to the OFF position. (9) Make sure the left override fuel boost pump PRESS light goes OFF. (10) Push in the left override fuel boost pump GFI control relay K10011 RESET button. Make sure the RESET button does not move up and the white band is not visible.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 30 of 50 **BOEING SERVICE BULLETIN 757-28A0079**(11) Push the left override fuel boost pump (LEFT C PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (12) Listen and make sure the left override fuel boost pump operates. (13) Make sure the left override fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE LEFT OVERRIDE FUEL BOOST PUMP (LEFT C PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (14) Push the left override fuel boost pump switch-light to the OFF position. (15) Listen and make sure the left override fuel boost pump does not operate. **NOTE:** The left override fuel boost pump PRESS light stays off when the pump switch is turned to OFF. j. Do a test of the right aft fuel boost pump control relay (K189) located in the P37 panel as shown below. **Right Aft Fuel Boost Pump Control Relay - Operation** (1) Push the right aft fuel boost pump (R AFT PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (2) Listen and make sure the right aft fuel boost pump operates. (3) Make sure the right aft fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE RIGHT AFT FUEL BOOST PUMP (R AFT PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push the right aft fuel boost pump (R AFT PUMP) switch-light to the OFF position. (5) Listen and make sure the right aft fuel boost pump does not operate. (6) Make sure the right aft fuel boost pump PRESS light comes on. **Right Aft Fuel Boost Pump - Ground Fault Interruption Function** (1) Push the right aft fuel boost pump (R AFT PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (2) Listen and make sure the right aft fuel boost pump operates. (3) Make sure the right aft fuel boost pump PRESS light on the P5-2 fuel management control panel goes off.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 31 of 50 **BOEING SERVICE BULLETIN 757-28A0079 CAUTION:**  IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE RIGHT AFT FUEL BOOST PUMP (R AFT PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push the right aft fuel boost pump GFI control relay K189 TEST button. (5) Listen and make sure the right aft fuel boost pump does not operate. (6) Make sure the right aft fuel boost pump PRESS light comes on. (7) Make sure the right aft fuel boost pump GFI control relay K189 RESET button has moved up so that a white band is visible. **NOTE:** The RESET button located at the top edge of GFI relay (K189) moves up, to expose a narrow, white band when the GFI circuit turns off the K189 relay due to a ground fault, or results when you push the TEST button located on the top surface of the K189 relay. (8) Push the right aft fuel boost pump (R AFT PUMP) switch-light to the OFF position. (9) Push in the right aft fuel boost pump GFI control relay K189 RESET button. Make sure the RESET button does not move up and the white band is not visible. (10) Push the right aft fuel boost pump (R AFT PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (11) Listen and make sure the right aft fuel boost pump operates. (12) Make sure the right aft fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE RIGHT AFT FUEL BOOST PUMP (R AFT PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (13) Push the right aft fuel boost pump (R AFT PUMP) switch-light to the OFF position. (14) Listen and make sure the right fuel boost pump does not operate. (15) Make sure the right aft fuel boost pump PRESS light on the P5-2 fuel management control panel comes on. k. Do a test of the right forward fuel boost pump control relay (K190) located in the P33 panel as shown below.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 32 of 50 **BOEING SERVICE BULLETIN 757-28A0079 Right Forward Fuel Boost Pump Control Relay - Operation**  (1) Push the right forward fuel boost pump (R FWD PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (2) Listen and make sure the right forward fuel boost pump operates. (3) Make sure the right forward fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE RIGHT FORWARD FUEL BOOST PUMP (R FWD PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push the right forward fuel boost pump (R FWD PUMP) switch-light to the OFF position. (5) Listen and make sure the right forward fuel boost pump does not operate. (6) Make sure the right forward fuel boost pump PRESS light comes on. **Right Forward Fuel Boost Pump - Ground Fault Interruption Function** (1) Push the right forward fuel boost pump (R FWD PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (2) Listen and make sure the right forward fuel boost pump operates. (3) Make sure the right forward fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE RIGHT FORWARD FUEL BOOST PUMP (R FWD PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push the right forward fuel boost pump GFI control relay K190 TEST button. (5) Listen and make sure the right forward fuel boost pump does not operate. (6) Make sure the right forward fuel boost pump PRESS light comes on. (7) Make sure the right forward fuel boost pump GFI control relay K190 RESET button has moved up so that a white band is visible. **NOTE:** The RESET button located at the top edge of GFI relay (K190) moves up, to expose a narrow, white band when the GFI circuit turns off the K190 relay due to a ground fault, or results when you push the TEST button located on the top surface of the K190 relay. (8) Push the right forward fuel boost pump (R FWD PUMP) switch-light to the OFF position.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 33 of 50 **BOEING SERVICE BULLETIN 757-28A0079**(9) Push in the right forward fuel boost pump GFI control relay K190 RESET button. Make sure the RESET button does not move up and the white band is not visible. (10) Push the right forward fuel boost pump (R FWD PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (11) Listen and make sure the right forward fuel boost pump operates. (12) Make sure the right forward fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE RIGHT FORWARD FUEL BOOST PUMP (R FWD PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (13) Push the right forward fuel boost pump (R FWD PUMP) switch-light to the OFF position. (14) Listen and make sure the right forward fuel boost pump does not operate. (15) Make sure the right forward fuel boost pump PRESS light on the P5-2 fuel management control panel comes on. l. Do a test of the right override fuel boost pump control relay (K10012) located in the P37 panel as shown below. **Right Override Fuel Boost Pump Control Relay - Operation** (1) Push the right override fuel boost pump (RIGHT C PUMP) switch-light on the P5-2 fuel management control panel at the P5 overhead panel to the ON position. (2) Listen and make sure the right override fuel boost pump operates. (3) Make sure the right override fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **NOTE:** Low pressure (PRESS) light comes on momentarily after the pump switch is set to the ON position. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE RIGHT OVERRIDE FUEL BOOST PUMP (RIGHT C PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push the right override fuel boost pump (RIGHT C PUMP) switch-light to the OFF position. (5) Listen and make sure the right override fuel boost pump does not operate. **NOTE:** The right override fuel boost pump PRESS light stays off when the pump switch is turned to OFF.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 34 of 50 **BOEING SERVICE BULLETIN 757-28A0079 Right Override Fuel Boost Pump - Ground Fault Interruption Function**  (1) Push the right override fuel boost pump (RIGHT C PUMP) switch-light on the P5-2 fuel management control panel to the ON position. (2) Listen and make sure the right override fuel boost pump operates. (3) Make sure the right override fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **NOTE:** Low pressure (PRESS) light comes on momentarily after the pump switch is set to the ON position. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE RIGHT OVERRIDE FUEL BOOST PUMP (RIGHT C PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (4) Push the right override fuel boost pump control GFI relay K10012 TEST button. (5) Listen and make sure the right override fuel boost pump does not operate. (6) Make sure the right override fuel boost pump PRESS light comes on. (7) Make sure the right override fuel boost pump GFI control relay K10012 RESET button has moved up so that a white band is visible. **NOTE:** The RESET button located at the top edge of GFI relay (K10012) moves up, to expose a narrow, white band when the GFI circuit turns off the K10012 relay due to a ground fault, or results when you push the TEST button located on the top surface of the K10012 relay. (8) Push the right override fuel boost pump switch-light to the OFF position. (9) Make sure the right override fuel boost pump PRESS light goes OFF. (10) Push the right override fuel boost pump GFI control relay K10012 RESET button in. Make sure the RESET button does not move up and the white band is not visible. (11) Push the right override fuel boost pump (RIGHT C PUMP) switch-light on the P5-2 fuel management control panel to the ON position, (12) Listen and make sure the right override fuel boost pump operates.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 35 of 50 **BOEING SERVICE BULLETIN 757-28A0079**(13) Make sure the right override fuel boost pump PRESS light on the P5-2 fuel management control panel goes off. **CAUTION:** IF THE AMBER LOW PRESSURE (PRESS) LIGHT STAYS ON, SET THE RIGHT OVERRIDE FUEL BOOST PUMP (RIGHT C PUMP) SWITCH-LIGHT TO THE OFF POSITION. FIND THE CAUSE, THEN RESTART TEST FROM STEP (1) ABOVE. (14) Push theright override fuel boost pump (RIGHT C PUMP) switch-light to the OFF position. (15) Listen and make sure the right override fuel boost pump does not operate. **NOTE:** The right override fuel boost pump PRESS light stays off when the pump switch is turned to OFF. m. Do the following tests of the fuel boost pumps to make sure there is sufficient fuel pump pressure. **NOTE:** If the relay installation was not correct, the pumps operate but may not give sufficient pressure. The test steps below make sure that the operation of the pumps is correct. **Operation of the Left Fuel Override Pump - Transfer Fuel from Center Tank to Left Main Tank**  (1) Record the fuel quantity for the left, center, and right tanks. (Quantity 1) (2) Do the setup to transfer fuel from the center tank to the left main tank with the left fuel override pump. Refer to 757 AMM 28-26-00 as an accepted procedure. (3) Turn the left fuel override pump (LEFT C PUMP) switch on the P5-2 fuel management control panel to ON for a period of two minutes. (4) Turn the left fuel override pump (LEFT C PUMP) switch on the P5-2 fuel management control panel to OFF after two minutes. (5) Record the fuel quantity for the left, center, and right tanks. (Quantity 2) (6) Calculate the amount of fuel that was transferred from the center tank to the left main tank: Left Tank Quantity 2 - Left Tank Quantity 1 = Fuel Transferred Left. Center Tank Quantity 1 - Center Tank Quantity 2 = Fuel Transferred Center. (7) Make sure Fuel Transferred Left is more than or equal to 400 pounds (200 kilograms). If the Fuel Transferred Left is less than 400 pounds, check the phase relationship of the wiring at the K10011 relay. (8) Make sure Fuel Transferred Center is more than 400 pounds. If the Fuel Transferred Center is less than 400 pounds (200 kilograms), check the phase relationship of the wiring at the K10011 relay.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 36 of 50 **BOEING SERVICE BULLETIN 757-28A0079 Operation of the Left Aft Fuel Boost Pump - Transfer Fuel from the Left Main (Aft) Tank**  **to Center Tank** (1) Do the setup to transfer fuel from the left main tank to the center tank with the left aft fuel boost pump. Refer to 757 AMM 28-26-00 as an accepted procedure. (2) Turn the left aft fuel boost pump (L AFT PUMP) switch on the P5-2 fuel management control panel to ON for a period of two minutes. (3) Turn the left aft fuel boost pump (L AFT PUMP) switch on the P5-2 fuel management control panel to OFF after two minutes. (4) Record the fuel quantity for the left, center, and right tanks. (Quantity 3) (5) Calculate the amount of fuel that was transferred from the left main tank to the center tank: Center Tank Quantity 3 - Center Tank Quantity 2 = Fuel Transferred Center. Left Tank Quantity 2 - Left Tank Quantity 3 = Fuel Transferred Left. (6) Make sure Fuel Transferred Center is more than or equal to 200 pounds (100 kilograms). If the Fuel Transferred Center is less than 200 pounds (100 kilograms), check the phase relationship of the wiring at the K187 relay. (7) Make sure Fuel Transferred Left is more than or equal to 200 pounds (100 kilograms). If the Fuel Transferred Left is less than 200 pounds (100 kilograms), check the phase relationship of the wiring at the K187 relay. **Operation of the Left Forward Fuel Boost Pump - Left Main (Forward) Tank to Center Tank**  (1) Do the setup to transfer fuel from the left main tank to the center tank with the left forward fuel boost pump. Refer to 757 AMM 28-26-00 as an accepted procedure. (2) Turn the left forward fuel boost pump (L FWD PUMP) on the P5-2 fuel management control panel to ON for a period of two minutes. (3) Turn the left forward fuel boost pump (L FWD PUMP) on the P5-2 fuel management control panel to OFF after two minutes. (4) Record the fuel quantity for the left, center, and right tanks. (Quantity 4)

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 37 of 50 **BOEING SERVICE BULLETIN 757-28A0079**(5) Calculate the amount of fuel that was transferred from the left main tank to the center tank: Center Tank Quantity 4 - Center Tank Quantity 3 = Fuel Transferred Center. Left Tank Quantity 3 - Left Tank Quantity 4 = Fuel Transferred Left. (6) Make sure Fuel Transferred Center is more than or equal to 200 pounds (100 kilograms). If the Fuel Transferred Center is less than 200 pounds (100 kilograms) check the phase relationship of the wiring at the K188 relay. (7) Make sure Fuel Transferred Left is more than 200 pounds (100 kilograms). If the Fuel Transferred Left is less than 200 pounds, check the phase relationship of the wiring at the K188 relay. **Operation of the Right Override Fuel Boost Pump - Center Tank to Right Main Tank** (1) Do the setup to transfer fuel from the center tank to the right main tank with the right override fuel boost pump. Refer to 757 AMM 28-26-00 as an accepted procedure. (2) Turn the right override fuel boost pump (RIGHT C PUMP) switch on the P5-2 fuel management control panel to ON for a period of two minutes. (3) Turn the right override fuel boost pump (RIGHT C PUMP) switch on the P5-2 fuel management control panel to OFF after two minutes. (4) Record the fuel quantity for the left, center, and right tanks. (Quantity 5) (5) Calculate the amount of fuel that was transferred from the center tank to the right main tank: Right Tank Quantity 5 - Right Tank Quantity 4 = Fuel Transferred Right. Center Tank Quantity 4 - Center Tank Quantity 5 = Fuel Transferred Center. (6) Make sure Fuel Transferred Right is more than or equal to 400 pounds (200 kilograms). If the Fuel Transferred Right is less than 400 pounds (200 kilograms), check the phase relationship of the wiring at the K10012 relay. (7) Make sure Fuel Transferred Center is more than or equal to 400 pounds (200 kilograms). If the Fuel Transferred Center is less than 400 pounds (200 kilograms), check the phase relationship of the wiring at the K10012 relay. **Operation of the Right Aft Fuel Boost Pump - Right Main (Aft) Tank to Center Tank** (1) Do the setup to transfer fuel from the right main tank to the center tank with the right aft fuel boost pump. (2) Turn the right aft fuel boost pump (R AFT PUMP) switch on the P5-2 fuel management control panel to ON for a period of two minutes. (3) Turn the right aft fuel boost pump (R AFT PUMP) switch on the P5-2 fuel management control panel to OFF after two minutes.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 38 of 50 **BOEING SERVICE BULLETIN 757-28A0079**(4) Record the fuel quantity for the left, center, and right tanks. (Quantity 6) (5) Calculate the amount of fuel that was transferred from the right main tank to the center tank: Center Tank Quantity 6 - Center Tank Quantity 5 = Fuel Transferred Center. Right Tank Quantity 5 - Right Tank Quantity 6 = Fuel Transferred Right. (6) Make sure Fuel Transferred Center is more than or equal to 200 pounds (100 kilograms). If the Fuel Transferred Center is less than 200 pounds (100 kilograms), check the phase relationship of the wiring at the K189 relay. (7) Make sure Fuel Transferred Right is more than 200 pounds (100 kilograms). If the Fuel Transferred Right is less than 200 pounds (100 kilograms), check the phase relationship of the wiring at the K189 relay. **Operation of the Right Forward Fuel Boost Pump - Right Main (Forward) Tank to Center Tank**  (1) Do the setup to transfer fuel from the right main tank to the center tank with the right forward fuel boost pump. Refer to 757 AMM 28-26-00 as an accepted procedure. (2) Turn the right forward fuel boost pump (R FWD PUMP) switch on the P5-2 fuel management control panel to ON for a period of two minutes. (3) Turn the right forward fuel boost pump (R FWD PUMP) switch on the P5-2 fuel management control panel to OFF after two minutes. (4) Record the fuel quantity for the left, center, and right tanks. (Quantity 7) (5) Calculate the amount of fuel that was transferred from the right main tank to the center tank: Center Tank Quantity 7 - Center Tank Quantity 6 = Fuel Transferred Center. Right Tank Quantity 6 - Right Tank Quantity 7 = Fuel Transferred Right. (6) Make sure Fuel Transferred Center is more than or equal to 200 pounds (100 kilograms). If the Fuel Transferred Center is less than 200 pounds (100 kilograms), check the phase relationship of the wiring at the K190 relay. (7) Make sure Fuel Transferred Right is more than 200 pounds or equal to (100 kilograms). If the Fuel Transferred Right is less than 200 pounds (100 kilograms), check the phase relationship of the wiring at the K190 relay. 14. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 39 of 50 **BOEING SERVICE BULLETIN 757-28A0079 Group 1, Configuration 2:**  **PART 2 - GFI RELAY INSTALLATION SCREW INSPECTION AND RELAY ELECTRICAL BONDING**  **CHECK - FOR AIRPLANES THAT HAVE PREVIOUSLY INCORPORATED THE ORIGINAL ISSUE**  **OF THIS SERVICE BULLETIN.** 1. Remove electrical power from the airplane. Refer to 757 AMM 24-22-00 as an accepted procedure. 2. Disconnect the battery connectors from the batteries. Refer to 757 AMM 24-31-01 (for the main battery) and 757 AMM 24-31-03 (for the Auxiliary Power Unit battery) as accepted procedures. 3. Open these circuit breakers. Attach a DO-NOT-CLOSE tag to each opened circuit breaker:
**Circuit Breaker Name**  **Panel / Location** C369 L FUEL OVRD PUMP P6-3 / F14 C370 R FUEL OVRD PUMP P6-4 / F20 C366 L AFT FUEL BOOST PUMP P6-3 / H14 C368 R FWD FUEL BOOST PUMP P6-3 / H17 C371 R AFT FUEL BOOST PUMP P6-4 / H20 C372 L FWD FUEL BOOST PUMP P6-4 / H23 4. Get access to the Main Equipment Center (MEC). 5. On the P33 Panel, Plate C, do a General Visual Inspection (GVI), for correct grip length, on the installation screws for GFI relays K187, K10011 and K190. Refer to SOPM 20-50-01 for more data on correct grip lengths. Make sure the chamfer on the shaft of each installation screw can be seen above the nut plate. Also, make sure that not more than three full threads of each installation screw can be seen above the nut plate. The P33 Panel, Plate C, has four screws, one at each corner, remove these screws to get access. If any of the GFI relay installation screws do not have the correct grip length, replace them with new screws, P/N NAS1801-08-7 (BACS12HN08-7 optional). **NOTE:** Refer to 757-300 SRM 51-40-02 for more data on the installation and removal of screws. Refer to 757-300 SRM 51-40-03 for more data on the substitution of screws. Refer to 757-300 SRM 51-40-04 for torque values. 6. On the P37 Panel, Plate B, do a General Visual Inspection (GVI), for correct grip length, on the installation screws for GFI relays K188, K189 and K10012. Refer to SOPM 20-50-01 for more data on correct grip lengths. Make sure the chamfer on the shaft of each installation screw can be seen above the nut plate. Also, make sure that not more than three full threads of each installation screw can be seen above the nut plate. The P37 Panel, Plate B, has two screws on top and a hinge on the bottom. The screws can be removed and the plate lowered to get access. If any of the GFI relay installation screws do not have the correct grip length, replace them with new screws, P/N BACS12HN08-7. **NOTE:** Refer to 757-300 SRM 51-40-02 for more data on the installation and removal of screws. Refer to 757-300 SRM 51-40-03 for more data on the substitution of screws. Refer to 757-300 SRM 51-40-04 for torque values.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 40 of 50 **BOEING SERVICE BULLETIN 757-28A0079**7. Measure the electrical bonding resistance between each GFI Relay K187, K10011, K190 and P33 Panel, Plate C in accordance with FIGURE 4. 8. Measure the electrical bonding resistance between each GFI Relay K188, K189, K10012 and P37 Panel, Plate B in accordance with FIGURE 5. 9. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2: January 11, 2012 41 of 50 **BOEING SERVICE BULLETIN 757-28A0079 This Figure applies only to: Group 1, Configuration 1.** 

**FIGURE 1: P33 PANEL PLATE 'C' - GROUND FAULT INTERRUPTER (GFI) RELAY - REPLACEMENT (SHEET 1 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2 January 11, 2012 42 of 50 **BOEING SERVICE BULLETIN 757-28A0079**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  If the removedscrews are not damaged and are length -7 they can be keptand re-installed. Replace any removed screw that is not a - 7 grip length. (c) 12 NAS1801-08-( )(BACS12HN08-( ) optional) Screw Remove / Keep 1

3 MS27418-2A Relay Remove (b) 3 9324G-10676 Relay Install (New) 2 Make sure the installed screws have the correct grip length. Refer to SOPM 20-50-01 for more data on correct grip lengths. (c) (d) 12 NAS1801-08-7(BACS12HN08-7 optional) Screw Install (Kept)

On the P33 Panel. (a) - - Service Bulletin Num- ber Apply 3 (a) Apply on the P33 Panel "SB 757-28A0079 R02 Incorporated", and the incorporation date. Refer to SOPM 20-50-10 as an accepted procedure. (b) Refer to 757 AMM 28-22-15 as an accepted procedure. Solvent clean the GFI Relay mounting flanges and the Plate C, P33 Panel. Refer to SOPM 20-11-03, CM3, as an accepted procedure. (c) Refer to 757-300 SRM 51-40-02 for more data on the installation and removal of screws. Refer to 757- 300 SRM 51-40-03 for more data on the substitution of screws. (d) Refer to 757-300 SRM 51-40-04 for torque values.

**FIGURE 1: P33 PANEL PLATE 'C' - GROUND FAULT INTERRUPTER (GFI) RELAY - REPLACEMENT (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2 January 11, 2012 43 of 50 **BOEING SERVICE BULLETIN 757-28A0079 This Figure applies only to: Group 1, Configuration 1.** 

**FIGURE 2: P37 PANEL PLATE 'B' - GROUND FAULT INTERRUPTER (GFI) RELAY - REPLACEMENT (SHEET 1 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2 January 11, 2012 44 of 50 **BOEING SERVICE BULLETIN 757-28A0079**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  If the removedscrews are not damaged and are length -7 they can be keptand re-installed. Replace any removed screw that is not a - 7 grip length. (c) 12 NAS602-( )(BACS12CK08-( ) optional) Screw Remove / Keep 1

3 MS27418-2A Relay Remove (b) 3 9324G-10676 Relay Install (New) 2 Make sure the installed screws have the correct grip length. Refer to SOPM 20-50-01 for more data on correct grip lengths. 12 NAS602-7P (BACS12CK08-7 orBACS12HN08-7 optional) Screw Install (Kept)

On the P37 Panel. (a) - - Service Bulletin Num- ber Apply 3 (a) Apply on the P37 Panel "SB 757-28A0079 R02 Incorporated", and the incorporation date. Refer to SOPM 20-50-10 as an accepted procedure. (b) Refer to 757 AMM 28-22-15 as an accepted procedure. Solvent clean the GFI Relay mounting flanges and the Plate B, P37 Panel. Refer to SOPM 20-11-03, CM3 as an accepted procedure. (c) Refer to 757-300 SRM 51-40-02 for more data on the installation and removal of screws. Refer to 757- 300 SRM 51-40-03 for more data on the substitution of screws. (d) Refer to 757-300 SRM 51-40-04 for torque values.

**FIGURE 2: P37 PANEL PLATE 'B' - GROUND FAULT INTERRUPTER (GFI) RELAY - REPLACEMENT (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2 January 11, 2012 45 of 50 **BOEING SERVICE BULLETIN 757-28A0079 This Figure applies only to: Group 1, Configuration 1.** 

**FIGURE 3: FUEL BOOST PUMP CONTROL GROUND FAULT INTERRUPTER (GFI) CONTROL RELAY SCHEMATIC REFERENCE**  **(SHEET 1 OF 1)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2 January 11, 2012 46 of 50 **BOEING SERVICE BULLETIN 757-28A0079**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a)

- K187 GFI RELAY Measure 1 (a)

- K10011 GFI RELAY Measure 2 (a)

- K190 GFI RELAY Measure 3 (a) Make sure the electrical bonding resistance between the GFI Relay mounting flange and P33 Panel, Plate C, is less than or equal to 0.0025 Ohms (2.5 milliohms). If the electrical bonding resistance is more than 0.0025 Ohms (2.5 milliohms) between the GFI Relay mounting flange and P33 Panel, Plate C, repair the

**FIGURE 4: P33 PANEL, PLATE C - GROUND FAULT INTERRUPTER (GFI) RELAY – ELECTRICAL BONDING RESISTANCE MEASUREMENTS**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2 January 11, 2012 47 of 50 **BOEING SERVICE BULLETIN 757-28A0079 MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** bond between the GFI Relay mounting flange and P33 Panel, Plate C. Refer to SWPM 20-20-00 and SOPM 20-11-03, CM3, as accepted procedures.

**FIGURE 4: P33 PANEL, PLATE C - GROUND FAULT INTERRUPTER (GFI) RELAY – ELECTRICAL BONDING RESISTANCE MEASUREMENTS**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2 January 11, 2012 48 of 50 **BOEING SERVICE BULLETIN 757-28A0079**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a)

- K188 GFI RELAY Measure 1 (a)

- K189 GFI RELAY Measure 2 (a)

- K10012 GFI RELAY Measure 3 (a) Make sure the electrical bonding resistance between the GFI Relay mounting flange and P37 Panel, Plate B, is less than or equal to 0.0025 Ohms (2.5 milliohms). If the electrical bonding resistance is more than 0.0025 Ohms (2.5 milliohms) between the GFI Relay mounting flange and P37 Panel, Plate B, repair the

**FIGURE 5: P37 PANEL, PLATE B - GROUND FAULT INTERRUPTER (GFI) RELAY – ELECTRICAL BONDING RESISTANCE MEASUREMENTS**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2 January 11, 2012 49 of 50 **BOEING SERVICE BULLETIN 757-28A0079 MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** bond between the GFI Relay mounting flange and P37 Panel, Plate B. Refer to SWPM 20-20-00 and SOPM 20-11-03, CM3, as accepted procedures.

**FIGURE 5: P37 PANEL, PLATE B - GROUND FAULT INTERRUPTER (GFI) RELAY – ELECTRICAL BONDING RESISTANCE MEASUREMENTS**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2008 757-28A0079 Revision 2 January 11, 2012 50 of 50 **BOEING SERVICE BULLETIN 757-28A0079**