Commercial 

Airplanes 757

Service Bulletin

Number: 757-28A0078

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.

ECCN: 9E991

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Unpublished Work - All Rights Reserved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,

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5.0
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BOEING SERVICE BULLETIN 757-28A0078

BLANK PAGE
Table of Contents

Revision Transmittal Sheet ............................................ 5

Summary ...................................................... 9

1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

E. Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2. Data supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . . 21

K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

A. Material - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . . . 23

3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

E. Special Tooling - Price and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . . . 24

3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

FIGURE 1: P33 PANEL, PLATE C - GROUND FAULT INTERRUPTER (GFI) RELAY - REPLACEMENT

[Group 1, Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

FIGURE 2: P37 PANEL, PLATE B - GROUND FAULT INTERRUPTER (GFI) RELAY - REPLACEMENT

[Group 1, Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

FIGURE 3: FUEL BOOST PUMP CONTROL GROUND FAULT INTERRUPTER (GFI) RELAY - SCHEMATIC

REFERENCE [Group 1, Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

FIGURE 4: P33 PANEL, PLATE C - GROUND FAULT INTERRUPTER (GFI) RELAY - ELECTRICAL

BONDING RESISTANCE MEASUREMENTS . . . . . . . . . . . . . . . . . . . . . . . . 49

FIGURE 5: P37 PANEL, PLATE B - GROUND FAULT INTERRUPTER (GFI) RELAY - ELECTRICAL

BONDING RESISTANCE MEASUREMENTS . . . . . . . . . . . . . . . . . . . . . . . . 51

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BOEING SERVICE BULLETIN 757-28A0078

BLANK PAGE
Commercial 

Airplanes 757

Service Bulletin

Revision Transmittal Sheet Number: 757-28A0078

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 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 and to change the reference of

SWPM 20-50-10 to SOPM 20-50-10. Also, the procedure for screw inspection and replacement is improved.

Figures 4 and 5 have been 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.

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8. 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 and added section detail.

15. Paragraph 2.C.2., Parts and Materials Supplied by the Operator: Applicability and parts table for Group 1,

Configuration 2 added. Optional screw, P/N BACS12HN08-7, added. Footnotes 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 missing steps added. Step order and title

changed. 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 757-28A0078 IN 02 and 757-28A0078 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.

REVISION HISTORY

Original Issue: July 16, 2008

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BOEING SERVICE BULLETIN 757-28A0078
Revision 1: August 24, 2010

Revision 2: January 11, 2012

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BLANK PAGE
Commercial 

Airplanes 757

Service Bulletin

Summary Number: 757-28A0078

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 the 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 relay feature will protect the fuel pumps

from damage caused by electrical arcing because the electrical power will be removed from the pump if a ground

fault is detected. 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 757-300 airplane service bulletin number is 757-28A0079.

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.

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EFFECTIVITY

757-200, 757-200CB and 757-200PF 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:

Total Task Hours Elapsed Hours

8.0 6.0

Group 1, Configuration 2:

Total Task Hours Elapsed Hours

3.0 3.0

MATERIAL INFORMATION

Operator Supplied Parts/Materials.

Refer to Paragraph 2.A., Material - Price and Availability.

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Commercial 

Airplanes 757

Service Bulletin

Number: 757-28A0078

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.

GROUP CONFIGURATION DESCRIPTION

1 - All 757-200, 757-200CB, and 757-200PF airplanes.

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:

757-200, 757-200CB, 757-200PF

Variable Number Group

NA001 - NA028 1

NA191 - NA199 1

NA201 - NA239 1

NA301 - NA305 1

NA341 - NA352 1

NA391 - NA399 1

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Variable Number Group

NA401 - NA408 1

NA441 - NA447 1

NA501 - NA586 1

NB001 - NB004 1

NB021 - NB023 1

NB036 - NB041 1

NB051 - NB053 1

NB061 - NB073 1

NB079 1

NB131 - NB148 1

NB161 - NB162 1

NB166 - NB168 1

NB201 - NB204 1

NB221 - NB228 1

NB230 1

NB236 1

NB239 1

NB261 - NB267 1

NB291 - NB299 1

NB301 - NB302 1

NB311 - NB312 1

NB321 - NB331 1

NB421 - NB438 1

NB446 1

NB451 - NB454 1

NB501 - NB523 1

NB561 1

NB571 1

NB581 - NB583 1

NC001 - NC033 1

NC041 - NC042 1

NC051 - NC052 1

NC056 - NC062 1

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BOEING SERVICE BULLETIN 757-28A0078
Variable Number Group

NC066 - NC084 1

NC091 - NC094 1

NC151 1

NC161 1

NC901 - NC951 1

NC971 - NC974 1

ND001 - ND007 1

ND011 - ND059 1

ND111 - ND113 1

ND161 - ND199 1

ND201 - ND203 1

ND221 - ND225 1

ND241 - ND248 1

ND301 - ND322 1

ND401 1

ND891 1

ND895 1

NE001 - NE008 1

NE011 - NE088 1

NE091 - NE094 1

NE141 - NE150 1

NE161 - NE177 1

NE201 - NE204 1

NE301 - NE302 1

NE311 - NE325 1

NJ001 - NJ004 1

NJ031 - NJ032 1

NJ551 - NJ555 1

NN001 - NN002 1

NN051 - NN052 1

NP901 - NP904 1

NS601 - NS616 1

NT001 - NT009 1

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BOEING SERVICE BULLETIN 757-28A0078
Variable Number Group

NT201 - NT202 1

NT231 - NT234 1

NT237 - NT240 1

NT242 1

NT245 - NT248 1

NT281 - NT289 1

NT341 - NT347 1

NT351 - NT360 1

NT371 - NT373 1

NT375 - NT379 1

NT381 - NT386 1

NT401 - NT409 1

NT411 - NT412 1

NT426 - NT427 1

NT431 - NT432 1

NT436 - NT438 1

NT441 - NT442 1

NT446 1

NT701 - NT769 1

NT791 - NT796 1

NT861 - NT862 1

NT881 - NT885 1

NT901 - NT916 1

NT971 - NT985 1

NU031 - NU038 1

2. Spares Affected

None.

B. Concurrent Requirements

None.

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BOEING SERVICE BULLETIN 757-28A0078
C. Reason

This service bulletin gives the 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 relay feature will protect

the fuel pumps from damage caused by electrical arcing because the electrical power will be removed

from the pump if a ground fault is detected. 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 757-300 airplane service bulletin number is 757-28A0079.

Revision 1 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 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 757-200 SRM 51-40-02, 757-200CB SRM 51-40-02,

757-200PF SRM 51-40-02, 757-200CB SRM 51-40-03, 757-200PF, SRM 51-40-03 and 757-200

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.

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 steps 3.B.1.PART 1.7 and 8. Also added new PART 2.

7. Revised FIGURE 1 step table to add new sub-steps.

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BOEING SERVICE BULLETIN 757-28A0078
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 757-28A0078 IN 01 was included in Revision 1.

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 and to change the reference of SWPM 20-50-10 to SOPM 20-50-10.

Also, the procedure for screw inspection and replacement is improved. Figures 4 and 5 have been

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 757-28A0078 IN 02 and 757-28A0078 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 the sure 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.

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 if necessary,

then measure the electrical bonding resistance of the GFI relay and repair the bond if necessary.

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BOEING SERVICE BULLETIN 757-28A0078
The work in this service bulletin is done in the maintenance zone(s) given below.

Affected Maintenance Zones

Model Zone

757-200, 757-200CB, 757- 119

200PF

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.

Group 1, Configuration 1:

Number of Per- Task-Hours Elapsed Hours

sons

Task

Open Access 1 0.75 0.75

Change 1 2.5 2.5

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Group 1, Configuration 1:

Number of Per- Task-Hours Elapsed Hours

sons

Task

Close Access 1 0.75 0.75

Test 2 4.0 2.0

TOTAL FOR EACH AIRPLANE 8.0 6.0

Group 1, Configuration 2:

Number of Per- Task-Hours Elapsed Hours

sons

Task

Open Access 1 0.75 0.75

Inspect 1 1.5 1.5

Close Access 1 0.75 0.75

TOTAL FOR EACH AIRPLANE 3.0 3.0

H. Weight and Balance Changes

Group 1, Configuration 1:

Change in Moment

(Pound-Inches)

Change in Weight

(Pounds)

Airplane

757-200 + 1.6 + 640.0

Group 1, Configuration 2:

None.

I. Electrical Load Data

1. Direct Current (DC) Loads:

None.

2. Alternating Current (AC) Loads

Group 1, Configuration 1:

Volt-Ampere- Phase Bus

Reactive

(VARs)

Airplanes Watts

757-200 - 0.53 0.52 C 115V AC BUS LEFT - SECTION 1

757-200 - 1.06 1.04 C 115V AC BUS LEFT - SECTION 3

757-200 - 0.53 0.52 C 115V RIGHT AC TRANSFER BUS

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Group 1, Configuration 1:

Volt-Ampere- Phase Bus

Reactive

(VARs)

Airplanes Watts

757-200 - 0.53 0.52 C 115V AC GROUND SERVICE BUS

757-200 - 0.53 0.52 C 115V AC BUS RIGHT - SECTION 3

Group 1, Configuration 2:

None.

3. Type

Continuous.

J. References

1. Existing Data:

a. Engineering Change Memo PRR 55000-10RS.

b. Boeing Service Bulletin 757-28A0079.

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. 757-200 Structural Repair Manual (SRM) 51-40-02, 51-40-03, 51-40-04.

i. 757-200CB Structural Repair Manual (SRM) 51-40-02, 51-40-03, 51-40-04.

j. 757-200PF 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:

Drawing Number Title

284N1325 SHIELD INSTL-MISC ELEC EQUIP P33

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Drawing Number Title

284N1526 SHIELD INSTL-MISC ELEC EQUIP P37

284N1318 SHIELD ASSY-MISC ELEC EQUIP P33

284N1127 PANEL ASSY-RIGHT MISC. RELAY, P37

K. Publications Affected

1. Publications:

Publication Chapter-Section

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 28-22

Equipment List N/A

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.

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BOEING SERVICE BULLETIN 757-28A0078
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:

Part Number / QTY Name Existing Part Number Notes

Specification

9324G-10676 6 Relay MS27418-2A (a)

NAS1801-08-7 24 Screw n/a (b)

(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:

Part Number / QTY Name Existing Part Number Notes

Specification

NAS1801-08-7 - Screw n/a (a)

(BACS12HN08-7

optional)

(a) Replacement screws of correct grip length, as necessary.

3. Parts Modified and Reidentified:

None.

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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.

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BOEING SERVICE BULLETIN 757-28A0078
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

757-200 SRM 51-40-02, 757-200CB SRM 51-40-02 and 757-200PF SRM 51-40-02.

Alternate fasteners are listed in 757-200 SRM 51-40-03, 757-200CB SRM 51-40-03

and 757-200PF SRM 51-40-03.

5. Refer to 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. 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.

7. 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.

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8. The instructions in Paragraph 3.B., Work Instructions and the figures can include

operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated

Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing

Index contain data on versions of the tools or test equipment that you can use. It is

permitted to use replaced tools. It is not permitted to use superseded tools.

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.

The removed part can be discarded if a new or serviceable part is installed.

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.

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.

Switch Location Position

L FWD PUMP P5 Panel OFF

LEFT C PUMP P5 Panel OFF

R AFT PUMP P5 Panel OFF

RIGHT C PUMP P5 Panel OFF

R FWD PUMP P5 Panel OFF

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BOEING SERVICE BULLETIN 757-28A0078
Switch Location Position

L AFT PUMP P5 Panel OFF

L FUEL CONTROL P10 Stand CUTOFF

R FUEL CONTROL P10 Stand CUTOFF

L FIRE HANDLE P8 Stand NORMAL

R FIRE HANDLE P8 Stand NORMAL

APU FIRE SWITCH P8 Stand NORMAL

4. Open these circuit breakers. Attach a DO-NOT-CLOSE tag to each opened circuit breaker:

Panel / Location Name Circuit Breaker

P6-3 / F14 L FUEL OVRD PUMP C369

P6-4 / F20 R FUEL OVRD PUMP C370

P6-3 / H14 L AFT FUEL BOOST PUMP C366

P6-3 / H17 R FWD FUEL BOOST PUMP C368

P6-4 / H20 R AFT FUEL BOOST PUMP C371

P6-4 / H23 L FWD FUEL BOOST PUMP C372

5. Get access to the Main Equipment Center.

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 P33

Panel, Plate C, in accordance with FIGURE 4.

9. Measure the electrical bonding resistance between each GFI Relay K188, K189, K10012 and P37

Panel, Plate B, in accordance with FIGURE 5.

10. Remove the DO-NOT-CLOSE tags and close these circuit breakers:

Panel / Location Name Circuit Breaker

P6-3 / F14 L FUEL OVRD PUMP C369

P6-4 / F20 R FUEL OVRD PUMP C370

P6-3 / H14 L AFT FUEL BOOST PUMP C366

P6-3 / H17 R FWD FUEL BOOST PUMP C368

P6-4 / H20 R AFT FUEL BOOST PUMP C371

P6-4 / H23 L FWD FUEL BOOST PUMP C372

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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 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:

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:

Valve Location

Engine Fuel Shutoff Valve (Spar Rear Spar at LH IRSS 264.50

Valve) for the No. 1 Tank

Engine Fuel Shutoff Valve (Spar Rear Spar at RH IRSS 264.50

Valve) for the No. 2 Tank

The Crossfeed Valve(s) Rear Spar at LBL 13.70, WL 184.35

The Defuel Valve LH and RH Rear Spars at IRSS 206.75

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.

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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.

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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.

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(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.

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BOEING SERVICE BULLETIN 757-28A0078
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.

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BOEING SERVICE BULLETIN 757-28A0078
(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.

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BOEING SERVICE BULLETIN 757-28A0078
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.

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BOEING SERVICE BULLETIN 757-28A0078
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.

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BOEING SERVICE BULLETIN 757-28A0078
(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.

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BOEING SERVICE BULLETIN 757-28A0078
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.

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BOEING SERVICE BULLETIN 757-28A0078
(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 the right 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.

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BOEING SERVICE BULLETIN 757-28A0078
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)

(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.

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BOEING SERVICE BULLETIN 757-28A0078
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.

(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:

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BOEING SERVICE BULLETIN 757-28A0078
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.

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BOEING SERVICE BULLETIN 757-28A0078
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:

Panel / Location Name Circuit Breaker

P6-3 / F14 L FUEL OVRD PUMP C369

P6-4 / F20 R FUEL OVRD PUMP C370

P6-3 / H14 L AFT FUEL BOOST PUMP C366

P6-3 / H17 R FWD FUEL BOOST PUMP C368

P6-4 / H20 R AFT FUEL BOOST PUMP C371

P6-4 / H23 L FWD FUEL BOOST PUMP C372

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 757-200 SRM 51-40-02, 757-200CB SRM 51-40-02 or 757-200PF SRM 51-40-02

for more data on the installation and removal of screws. Refer to 757-200 SRM 51-40-03,

757-200CB SRM 51-40-03 or 757-200PF SRM 51-40-03 for more data on the substitution

of screws. Refer to 757-200 SRM 51-40-04, 757-200CB SRM 51-40-04 or 757-200PF

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. 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.

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BOEING SERVICE BULLETIN 757-28A0078
NOTE: Refer to 757-200 SRM 51-40-02, 757-200CB SRM 51-40-02 or 757-200PF SRM 51-40-02

for more data on the installation and removal of screws. Refer to 757-200 SRM 51-40-03,

757-200CB SRM 51-40-03 or 757-200PF SRM 51-40-03 for more data on the substitution

of screws. Refer to 757-200 SRM 51-40-04, 757-200CB SRM 51-40-04 or 757-200PF

SRM 51-40-04 for torque values.

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.

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BOEING SERVICE BULLETIN 757-28A0078
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)

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BOEING SERVICE BULLETIN 757-28A0078
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.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

If the removed

screws are not damaged and are length

-7 they can be kept

and re-installed. Replace any removed

screw that is not a -

7 grip length. (c)

NAS1801-08-( ) 12

(BACS12HN08-( ) optional)

1 Remove / Keep Screw

Remove Relay MS27418-2A 3

2 Install (New) Relay 9324G-10676 3 (b)

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)

NAS1801-08-7 12

(BACS12HN08-7 optional)

Install (Kept) Screw

On the P33 Panel.

(a)

Service Bulletin Num- - -

ber

3 Apply

(a) Apply on the P33 Panel "SB 757-28A0078 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 757-200 SRM 51-40-02, 757-200CB SRM 51-40-02 or 757-200PF SRM 51-40-02 for more data

on the installation and removal of screws. Refer to 757-200 SRM 51-40-03, 757-200CB SRM 51-40-03

or 757-200PF SRM 51-40-03 for more data on the substitution of screws.

(d) Refer to 757-200 SRM 51-40-04, 757-200CB SRM 51-40-04 or 757-200PF SRM 51-40-04 for torque

values.

FIGURE 1: P33 PANEL, PLATE C - GROUND FAULT INTERRUPTER (GFI) RELAY - REPLACEMENT

(SHEET 2 OF 2)

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BOEING SERVICE BULLETIN 757-28A0078
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)

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46 of 52

BOEING SERVICE BULLETIN 757-28A0078
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.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

If the removed

screws are not damaged and are length

-7 they can be kept

and re-installed. Replace any removed

screw that is not a -

7 grip length. (c)

NAS602-( ) 12

(BACS12CK08-( ) optional)

1 Remove / Keep Screw

Remove Relay MS27418-2A 3

2 Install (New) Relay 9324G-10676 3 (b)

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)

NAS602-7P 12

(BACS12CK08-7 or

BACS12HN08-7 optional)

Install (Kept) Screw

On the P37 Panel.

(a)

Service Bulletin Num- - -

ber

3 Apply

(a) Apply on the P37 Panel "SB 757-28A0078 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 757-200 SRM 51-40-02, 757-200CB SRM 51-40-02 or 757-200PF SRM 51-40-02 for more data

on the installation and removal of screws. Refer to 757-200 SRM 51-40-03, 757-200CB SRM 51-40-03

or 757-200PF SRM 51-40-03 for more data on the substitution of screws.

(d) Refer to 757-200 SRM 51-40-04, 757-200CB SRM 51-40-04 or 757-200PF SRM 51-40-04 for torque

values.

FIGURE 2: P37 PANEL, PLATE B - GROUND FAULT INTERRUPTER (GFI) RELAY - REPLACEMENT

(SHEET 2 OF 2)

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Original Issue: July 16, 2008

Revision 2 January 11, 2012 757-28A0078

47 of 52

BOEING SERVICE BULLETIN 757-28A0078
This Figure applies only to: Group 1, Configuration 1.

FIGURE 3: FUEL BOOST PUMP CONTROL GROUND FAULT INTERRUPTER (GFI) RELAY - SCHEMATIC

REFERENCE

(SHEET 1 OF 1)

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Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 16, 2008

Revision 2 January 11, 2012 757-28A0078

48 of 52

BOEING SERVICE BULLETIN 757-28A0078
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.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Measure GFI RELAY K187 - (a)

2 Measure GFI RELAY K10011 - (a)

3 Measure GFI RELAY K190 - (a)

(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)

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Copyright © Unpublished Work - See page 1 for details.

Original Issue: July 16, 2008

Revision 2 January 11, 2012 757-28A0078

49 of 52

BOEING SERVICE BULLETIN 757-28A0078
STEP TASK NAME IDENTIFICATION QTY MORE DATA

bond between the GFI Relay mounting flange and P33 panel, Plate C. Refer to SWPM 20-20-00 and

SOPM 20-11-03 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

Revision 2 January 11, 2012 757-28A0078

50 of 52

BOEING SERVICE BULLETIN 757-28A0078
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.

STEP TASK NAME IDENTIFICATION QTY MORE DATA

1 Measure GFI RELAY K188 - (a)

2 Measure GFI RELAY K189 - (a)

3 Measure GFI RELAY K10012 - (a)

(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

Revision 2 January 11, 2012 757-28A0078

51 of 52

BOEING SERVICE BULLETIN 757-28A0078
STEP TASK NAME IDENTIFICATION QTY MORE DATA

bond between the GFI Relay mounting flange and P37 panel, Plate B. Refer to SWPM 20-20-00 and

SOPM 20-11-03 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

Revision 2 January 11, 2012 757-28A0078

52 of 52

BOEING SERVICE BULLETIN 757-28A0078