# Boeing Service Bulletin 747-28-2340: No revision named - Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2016-6145; AD 2020-18-02 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Boeing Service Bulletin 747-28-2340](https://openairdocs.org/service-documents/boeing/sb-747-28-2340.md) - Title as filed: SB 747-28-2340 - Pages: 21 - PDF: https://openairdocs.org/files/sha256/ae/69/ae69ef14aa17600a90484c6b30a824c86083765db513d2ffabe0edb9cb489c3f - Page: https://openairdocs.org/service-documents/boeing/sb-747-28-2340/file/ae69ef14aa17 ## Text Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 Commercial Airplanes 747 Service Bulletin Number: 747-28-2340 Original Issue: June 06, 2014 ATA System: 2841 SUBJECT: FUEL - Fuel Quantity Indicating System (FQIS) - FQIS Ground Test and Corrective Action Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 300-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991ECCN: BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET Copyright © 2014 Boeing. Unpublished Work. All Rights Reserved. Treatment of this document and its content is governed by contract with Boeing. Rights to use this document are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The Boeing Company. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing. Original Issue: June 06, 2014 747-28-2340 1 of 21 3.0 ### Page 2 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 2 of 21 BOEING SERVICE BULLETIN 747-28-2340 BLANK PAGE ### Page 3 Table of Contents Summary ...................................................... 5 1. PLANNING INFORMATION ........................................ 7 A. Effectivity ................................................ 7 1. Airplanes ............................................. 7 2. Spares Affected ......................................... 9 B. Concurrent Requirements ....................................... 9 C. Reason ................................................. 9 D. Description .............................................. 1 0 E. Compliance .............................................. 1 0 F. Approval ............................................... 1 1 G. Manpower .............................................. 1 1 H. Weight and Balance Changes .................................... 1 2 I. Electrical Load Data ......................................... 1 2 J. References .............................................. 1 2 1. Existing Data: ......................................... 1 2 2. Data Supplied with this Service Bulletin: ........................... 1 2 3. Installation Drawings Used in the Preparation of this Service Bulletin: ........... 1 2 K. Publications Affected ........................................ 1 2 L. Interchangeability and Intermixability of Parts ........................... 1 3 M. Software Accomplishment Summary ................................ 1 3 2. MATERIAL INFORMATION ........................................ 1 5 A. Material - Price and Availability ................................... 1 5 B. Industry Support Information .................................... 1 5 C. Parts Necessary for Each Airplane ................................. 1 5 1. Kits/Parts ............................................ 1 5 2. Parts and Materials Supplied by the Operator ........................ 1 5 3. Parts Modified and Reidentified ................................ 1 5 4. Parts Removed and Not Replaced .............................. 1 5 D. Parts Necessary to Change Spares ................................. 1 5 E. Special Tooling - Price and Availability ............................... 1 5 F. Special Tooling Necessary to do this Service Bulletin ....................... 1 5 3. ACCOMPLISHMENT INSTRUCTIONS .................................. 1 7 A. GENERAL INFORMATION ..................................... 1 7 B. WORK INSTRUCTIONS ....................................... 1 8 APPENDIX A: LOGIC DIAGRAM ....................................... 2 1 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 3 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 4 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 4 of 21 BOEING SERVICE BULLETIN 747-28-2340 BLANK PAGE ### Page 5 Commercial Airplanes 747 Service Bulletin SummaryNumber: 747-28-2340Original Issue: June 06, 2014 ATA System: 2841 SUBJECT: FUEL - Fuel Quantity Indicating System (FQIS) - FQIS Ground Test and Corrective Action CONCURRENT REQUIREMENTS None. BACKGROUND This service bulletin gives instructions to do the Fuel Quantity Indicating System (FQIS) ground test every 750 flight hours on 747-400 freighters that do not have the Nitrogen Generating System (NGS) installed. This service bulletin also gives instructions for corrective action before further flight if one or more specified center wing tank (CWT) FQIS faults are found. If this service bulletin is not done, one or more of these FQIS faults could go undetected, which along with a second fault could result in a potential source of ignition in the CWT and consequent fire or explosion. An FAA review of the Boeing safety assessment required by Special Federal Aviation Regulation (SFAR) 88 identified an unsafe condition on delivered and modified freighter airplanes that do not have NGS installed to reduce flammability in the CWT. For freighters without NGS, one or more of the specified FQIS faults inside the CWT, in combination with an electrical hot short to the CWT FQIS wiring outside the tank, can possibly create an ignition source in the CWT. The FQIS ground test uses the Built-In Test Equipment (BITE) function of the Fuel Quantity Processor Unit (FQPU) to check for fifteen (15) specified CWT FQIS faults, each of which could result in an ignition source if not found and corrected. Boeing Service Related Problem (SRP) 747-SRP-28-0149 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 747 FTD 28-13004 is related to this service bulletin. This table is provided to operators for planning purposes only. Refer to the applicable sections for more information. ReferenceAffectedPlanning Data Paragraph 1.A.2., Spares AffectedNoSpares Affected Paragraph 1.E., Compliance and Paragraph 1.F., Approval YesAD Related Paragraph 1.H., Weight and Balance ChangesNoWeight and Balance Change Paragraph 1.I., Electrical Load DataNoElectrical Load Changed Paragraph 1.K., Publications AffectedNoPublications Affected Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 5 of 21 ### Page 6 ReferenceAffectedPlanning Data Paragraph 1.K., Publications AffectedNoAirplane Flight Operations Affected (Flight Crew Operations Manual and/or FAA Approved Air- plane Flight Manual) Paragraph 2.C.1., Kits/PartsNoKits/Parts Required Paragraph 2.C.2., Parts and Materials Supplied by the Operator NoOperator Supplied Parts/Material Paragraph 2.F., Special Tooling Necessary to do this Service Bulletin NoSpecial Tooling Required ACTION Group 1, Configuration 1: No action required. Group 1, Configuration 2: Open access to the flight deck. Do the FQIS Ground Test. For each maintenance message related to a specified CWT FQIS fault, do the corrective action given in the Fault Isolation Manual (FIM). Close access. EFFECTIVITY 747-400F Airplanes, 747-400 Boeing Converted Freighters (BCF), and 747-400 Large Cargo Freighters (LCF). Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. COMPLIANCE The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Refer to Paragraph 1.E., Compliance. INDUSTRY SUPPORT INFORMATION Boeing warranty remedies are not available for the test and corrective action procedures given in this service bulletin. MANPOWER Elapsed HoursTotal Task HoursAirplanes 1.001.00Group 1, Configuration 2 MATERIAL INFORMATION None. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 6 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 7 Commercial Airplanes 747 Service Bulletin Number: 747-28-2340 Original Issue: June 06, 2014 ATA System: 2841 SUBJECT: FUEL - Fuel Quantity Indicating System (FQIS) - FQIS Ground Test and Corrective Action 1. PLANNING INFORMATION A. Effectivity 1. Airplanes This service bulletin is applicable to 747-400F airplanes, 747-400 Boeing Converted Freighters (BCF), and 747-400 Large Cargo Freighters (LCF), line numbers 1-1419, in 1 Group. The Variable Numbers and Group Information for the applicable airplanes is given below. Refer to Service Bulletin Index D6-30300 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. DESCRIPTIONCONFIGURATIONGROUP All affected airplanes-1 Airplanes with Boeing Service Bulletin (SB) 747-47-2006 incorporated. SB 747-47-2006 installs the Nitrogen Generation System (NGS). 1 Airplanes without SB 747-47-2006 incorporated.2 Airplane Models: 747-400, 747-400F GroupVariable Number 1RL401 - RL403 1RL411 - RL436 1RL451 - RL456 1RL461 - RL462 1RL471 - RL481 1RL491 - RL492 1RL501 - RL502 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 7 of 21 ### Page 8 GroupVariable Number 1RL511 - RL516 1RL521 - RL522 1RL531 - RL534 1RL551 1RL561 1RL563 - RL568 1RL571 - RL572 1RL576 - RL577 1RL579 1RL581 - RL586 1RL651 - RL655 1RL671 - RL675 1RL681 - RL684 1RL751 - RL752 1RM128 1RM851 - RM859 1RM861 - RM862 1RM871 - RM899 1RM901 - RM906 1RM911 1RR701 1RR721 - RR724 1RR746 - RR748 1RR851 - RR856 1RR861 - RR862 1RR951 - RR952 1RT021 - RT022 1RT031 - RT033 1RT061 1RT071 - RT072 1RT161 1RT164 1RT456 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 8 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 9 GroupVariable Number 1RT501 1RT506 - RT510 1RT513 1RT516 1RT518 - RT520 1RT524 1RT526 1RT528 1RT530 1RT572 - RT579 1RT631 - RT632 1RT642 1RT654 - RT657 1RT691 - RT692 1RT743 1RT751 - RT752 1RT781 - RT782 1RT837 1RT876 1RT967 2. Spares Affected None. B. Concurrent Requirements None. C. Reason This service bulletin gives instructions to do the Fuel Quantity Indicating System (FQIS) ground test every 750 flight hours on 747-400 freighters that do not have the Nitrogen Generating System (NGS) installed. This service bulletin also gives instructions for corrective action before further flight if one or more specified center wing tank (CWT) FQIS faults are found. If this service bulletin is not done, one or more of these FQIS faults could go undetected, which along with a second fault could result in a potential source of ignition in the CWT and consequent fire or explosion. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 9 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 10 An FAA review of the Boeing safety assessment required by Special Federal Aviation Regulation (SFAR) 88 identified an unsafe condition on delivered and modified freighter airplanes that do not have NGS installed to reduce flammability in the CWT. For freighters without NGS, one or more of the specified FQIS faults inside the CWT, in combination with an electrical hot short to the CWT FQIS wiring outside the tank, can possibly create an ignition source in the CWT. The FQIS ground test uses the Built-In Test Equipment (BITE) function of the Fuel Quantity Processor Unit (FQPU) to check for fifteen (15) specified CWT FQIS faults, each of which could result in an ignition source if not found and corrected. Boeing Service Related Problem (SRP) 747-SRP-28-0149 is related to this service bulletin. Boeing Fleet Team Digest (FTD) 747 FTD 28-13004 is related to this service bulletin. D. Description Group 1, Configuration 1: No action required. Group 1, Configuration 2: Open access to the flight deck. Do the FQIS Ground Test. For each maintenance message related to a specified CWT FQIS fault, do the corrective action given in the Fault Isolation Manual (FIM). Close access. The work in this service bulletin is done in the maintenance zone(s) given below. Affected Maintenance Zones ZoneModel 221, 222747-400, 747-400F 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. Group 1, Configuration 1: No compliance time is given. Group 1, Configuration 2: Do the required actions in accordance with Paragraph 3., Accomplishment Instructions. Group 1, Configuration 2: Table 1: FQIS Ground Test and Corrective Action Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Within 6 months after the original issue date of this service bulletin. Do PART 1: FQIS GROUND TEST. All Airplanes Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 10 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 11 Group 1, Configuration 2: Table 1: FQIS Ground Test and Corrective Action Repeat Interval (Not to Exceed) Compliance TimeActionCondition -Before further flight.CONDITION 1 (ACTION 1): Do PART 2: CORRECTIVE ACTION. CONDITION 1: CENTER WING TANK FQIS FAULT FOUND 750 flight hours (a)-CONDITION 1 (ACTION 2): Repeat PART 1: FQIS GROUND TEST. 750 flight hours (a)-CONDITION 2 (ACTION 1): Repeat PART 1: FQIS GROUND TEST. CONDITION 2: CENTER WING TANK FQIS FAULT NOT FOUND (a) Incorporation of Boeing Service Bulletin 747-47-2006, INERT GAS SYSTEM - Nitrogen Generation System - Installation, is the terminating action for the repeat tests. Group 1, Configuration 2: A logic diagram showing compliance tasks and compliance times is included as an aid in APPENDIX A. 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 Group 1, Configuration 1: No action required. Group 1, Configuration 2: The table below shows an estimate of the task hours necessary to do this test for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time:  Time to adjust to the workplace  Time to schedule the work  Time to inspect the work  Time to cure the materials  Time to make the parts  Time to find the tools. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 11 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 12 Group 1, Configuration 2: Elapsed HoursTask HoursNumber of PersonsTask 0.250.251Open Access 0.500.501Test (a) 0.250.251Close Access 1.001.00TOTAL FOR EACH AIRPLANE (a) This estimate does not include time necessary for corrective action. H. Weight and Balance Changes None. I. Electrical Load Data Not changed. J. References 1. Existing Data: a. Boeing Service Bulletin 747-47-2006 b. Boeing Service Related Problem (SRP) 747-SRP-28-0149 c. Service Bulletin Index D6-30300 d. 747 Fleet Team Digest (FTD) 28-13004 e. 747-400 Fault Isolation Manual (FIM) 28-41 2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: None. K. Publications Affected 1. Publications: None. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 12 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 13 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 Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. M. Software Accomplishment Summary Not affected. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 13 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 14 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 14 of 21 BOEING SERVICE BULLETIN 747-28-2340 BLANK PAGE ### Page 15 2. MATERIAL INFORMATION A. Material - Price and Availability None. B. Industry Support Information Boeing warranty remedies are not available for the test and corrective action procedures given in this service bulletin. C. Parts Necessary for Each Airplane 1. Kits/Parts None. 2. Parts and Materials Supplied by the Operator None. 3. Parts Modified and Reidentified None. 4. Parts Removed and Not Replaced None. D. Parts Necessary to Change Spares None. E. Special Tooling - Price and Availability None. F. Special Tooling Necessary to do this Service Bulletin No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 15 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 16 Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 16 of 21 BOEING SERVICE BULLETIN 747-28-2340 BLANK PAGE ### Page 17 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. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch – Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch – Angular tolerance is plus or minus 2 degrees – Hole dimensions for standard solid rivets and fasteners are in Structural Repair Manual (SRM) Chapter 51 – Torque Values: — Values for structural fasteners are given in 747-400 Structural Repair Manual, Chapter 51. — Values for airframe maintenance tasks are included in Chapter 20 of 747-400 Airplane Maintenance Manual (AMM). — Values for electrical maintenance tasks are included in Chapter 20 of Standard Wiring Practices Manual (SWPM). — Values for engine maintenance tasks are included in Chapter 70 of 747-400 Airplane Maintenance Manual (AMM). — Non-standard torque values for maintenance tasks are included in the applicable installation step. 4. 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. 5. Refer to APPENDIX A for logic diagram(s). Logic diagrams are provided as an aid only. Information contained in Paragraph 1.E., Compliance is the primary source for compliance times. Information in Paragraph 3.B., Work Instructions is the primary source for tasks required for compliance. 6. If it is necessary to remove more parts for access, you can remove those parts. If you can get access without removing identified parts, it is not necessary to remove all of the identified parts. Jacking and shoring limitations must be observed. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 17 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 18 7. When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When more than one ACTION is given for a CONDITION number or an OPTION number, do all of the ACTION numbers for that CONDITION number or OPTION number. 8. The compliance times for the actions in Paragraph 3.B., WORK INSTRUCTIONS are in Paragraph 1.E., Compliance. 9. Some steps in the Work Instructions are identified as Required for Compliance (RC). If this service bulletin is mandated by an Airworthiness Directive (AD), then the steps identified as RC must be done to comply with the AD. Alternative procedures for steps not identified with RC can be used if the RC steps can still be done as specified, and the airplane can be put back in a serviceable condition. An Alternative Method of Compliance (AMOC) is not necessary for deviations to steps that are not identified as RC. B. WORK INSTRUCTIONS Group 1, Configuration 1: No action required. Group 1, Configuration 2: 1. Make sure that these circuit breakers are closed and DO-NOT-CLOSE safety tags are removed: NameNumberColumnRowPanel FUEL QTY 1C101235DP6, Main Power Distribution Panel FUEL QTY 2C101246D FUEL LTS-HOT orC011439MP180, DC Power Distribution Panel FUEL PWR-HOT BAT FUELING LTS orC0114222FP414, Power Distribution Center - Left Panel FUELING PWR 2. On the flight deck, open access to the Control Display Unit (CDU) on the P9 panel. 3. Prepare the CDU for the Fuel Quantity Indicating System (FQIS) Ground Test: a. Push the MENU key on the CDU to show the MENU. b. Push the line select key (LSK) that is adjacent to . NOTE: IN PROGRESS shows during the test. 3. When IN PROGRESS goes out of view, look for PASS or FAIL> adjacent to shows: (1) RC - Push the LSK that is adjacent to FAIL> to see the GROUND TEST MSG pages for all of the faults. (2) RC - Push the NEXT PAGE key until you find all the GROUND MSG pages. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 19 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 20 (3) Make a list of all maintenance messages that show on the GROUND TEST MSG pages. (4) RC - Use Table 1 below to find if each maintenance message is related to a specified center wing tank FQIS fault. Table 1: Maintenance Messages Related to Center Wing Tank FQIS Faults Fault Isolation Manual Task (reference only) Message TextMaintenance Message 28-41 TASK 856TANK WIRING-CENTER HI-Z OPEN AT PROCESSOR28058 28-41 TASK 874TANK WIRING-CENTER HI-Z LOW RESISTANCE CENTER TO SHIELD 28078 28-41 TASK 891TANK WIRING-CENTER HI-Z SHORT SHIELD TO GROUND28097 28-41 TASK 900TANK WIRING-CENTER COMPENSATOR OPEN LO-Z28107 28-41 TASK 919TANK WIRING-CENTER COMPENSATOR SHORT LO-Z TO GROUND 28127 28-41 TASK 960TANK WIRING-CENTER PROBE 1 OPEN LO-Z28171 28-41 TASK 961TANK WIRING-CENTER PROBE 2 OPEN LO-Z28172 28-41 TASK 962TANK WIRING-CENTER PROBE 3 OPEN LO-Z28173 28-41 TASK 963TANK WIRING-CENTER PROBE 4 OPEN LO-Z28174 28-41 TASK 964TANK WIRING-CENTER PROBE 5 OPEN LO-Z28175 28-41 TASK 970TANK WIRING-CENTER PROBE 1 SHORT LO-Z TO GROUND28182 28-41 TASK 971TANK WIRING-CENTER PROBE 2 SHORT LO-Z TO GROUND28183 28-41 TASK 972TANK WIRING-CENTER PROBE 3 SHORT LO-Z TO GROUND28184 28-41 TASK 973TANK WIRING-CENTER PROBE 4 SHORT LO-Z TO GROUND28185 28-41 TASK 974TANK WIRING-CENTER PROBE 5 SHORT LO-Z TO GROUND28186 PART 2: CORRECTIVE ACTION 1. RC - For each maintenance message related to a center wing tank FQIS fault listed in Table 1, do corrective action to clear the fault. Corrective action is identified in the 28 - Maintenance Message Index of the Fault Isolation Manual. Refer to 747-400 FIM 28-41 as an accepted procedure. 2. RC - Do PART 1: FQIS GROUND TEST and do corrective action until all of the maintenance messages listed in Table 1 are cleared. Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: June 06, 2014 747-28-2340 20 of 21 BOEING SERVICE BULLETIN 747-28-2340 ### Page 21 (OCR) BOEING SERVICE BULLETIN 747-28-2340 DO PART 1: FQIS GROUND TEST WITHIN 6 MONTHS AFTER THE ORIGINAL ISSUE DATE OF THIS SERVICE BULLETIN CONDITION 1: CONDITION 2: CENTER WING TANK FQIS CENTER WING TANK FQIS FAULT FOUND FAULT NOT FOUND CONDITION 1 (ACTION 1) CONDITION 2 (ACTION 1): DO PART 2: CORRECTIVE REPEAT PART 1: FQIS ACTION BEFORE FURTHER GROUND TEST AT AN FLIGHT INTERVAL NOT TO EXCEED 750 FLIGHT HOURS CONDITION 1 (ACTION 2): REPEAT PART 1: FQIS GROUND TEST AT AN INTERVAL NOT TO EXCEED 750 FLIGHT HOURS 2340232 APPENDIX A: LOGIC DIAGRAM (SHEET 1 OF 1) Original Issue: June 06, 2014 Export Controlled ECCN: 9E991 - BOEING 747-28-2340 PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 21 of 21 --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. 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