# Citation 

# SERVICE BULLET**IN REVISION**  **Revision 1 SB680-24-11**



# TRANSMITTAL SHEET

This sheet transmits Revision 1 to SB680-24-11 which: (1) Changes Step 13 to add clarity. **NOTE:** This revision replaces the original issue of SB680-24-11 in its entirety. **NOTE:** Change bars and pointing hands are not used in this publication to denote revised material. This transmittal sheet provides a complete description of the changes made by this revision, except for editorial changes.

**REVISION COMPLIANCE** MANDATORY. Airplanes previously modified by this service bulletin need to do Step 13 of this revision.

**SUMMARY OF REVISIONS** Original Issue Dec 16/2010 Revision 1 Nov 15/2011

# Citation 

# SERVICE BULLETIN **SB680-24-11 TITLE**  ELECTRICAL POWER - FUEL CROSSFEED IMPROVEMENT

**EFFECTIVITY MODEL SERIAL NUMBERS**  680 (Citation Sovereign) -0001 thru -0289, -0291 thru -0296

**REASON** The crossfeed valve can open uncommanded and a boost pump activated during a one side electrical emergency situation. **DESCRIPTION** This service bulletin contains parts and instructions to add diodes to the fuel crossfeed wiring. **COMPLIANCE** MANDATORY. This service bulletin must be accomplished within 400 flight hours or one year from the date of receipt, whichever occurs first. A service bulletin published by Cessna Aircraft Company may be recorded as "completed" in an aircraft log only when the following requirements are satisfied: 1) The mechanic must complete all of the instructions in the service bulletin, including the intent therein. 2) The mechanic must correctly use and install all applicable parts supplied with the service bulletin kit. Only with written authorization from Cessna Aircraft Company can substitute parts or rebuilt parts be used to replace new parts. 3) The mechanic or airplane owner must use the technical data in the service bulletin only as approved and published. 4) The mechanic or airplane owner must apply the information in the service bulletin only to aircraft serial numbers identified in the “Effectivity” section of the bulletin. 5) The mechanic or airplane owner must use maintenance practices that are identified as acceptable standard practices in the aviation industry and governmental regulations. No individual or corporate organization other than Cessna Aircraft Company is authorized to make or apply any changes to a Cessna-issued service bulletin, service letter, or flight manual supplement without prior written consent from Cessna Aircraft Company. Cessna Aircraft Company is not responsible for the quality of maintenance performed to comply with this document, unless the maintenance is accomplished at a Cessna-owned Citation Service Center. **FLIGHT CREW OPERATIONS** No Changes

Dec 16/2010 680-24-11 Revision 1 - Nov 15/2011 Page 1 of 9

Cessna Aircraft Company, Citation Marketing Division, P.O. Box 7706, Wichita, KS 67277, U.S.A. 1-316-517-6000, Fax 1-316-517-8500 COPYRIGHT © 2010Dec 16/2010 680-24-11 Revision 1 - Nov 15/2011 Page 2 

# Citation 

# SERVICE BULLETIN **SB680-24-11 APPROVAL**  Cessna received FAA approval for the technical data in this publication that changes the airplane type design. The accomplishment instructions in the service bulletin are an amendment to the applicable maintenance manual or Instructions for Continued Airworthiness (ICA), and you must complete them for ongoing airworthiness compliance as required per 14 CFR, Part 43.13. **MANPOWER WORK PHASE MAN-HOURS**  Modification * **MATERIAL - Cost and Availability PART NUMBER AVAILABILITY**  **COST**

SB680-24-11 * * * Refer to the Manpower, Material - Cost and Availability, and Warranty sections in the attached Service Bulletin Supplemental Data sheet.

**CHANGE IN WEIGHT AND BALANCE** Negligible **REFERENCES** Cessna Model 680 Maintenance manual **PUBLICATIONS AFFECTED** Cessna Model 680 Wiring Diagram Manual Cessna Model 680 FAA Approved Airplane Flight Manual (68FM-09) Cessna Model 680 FAA Approved Airplane Flight Manual (68FM-10) **ACCOMPLISHMENT INSTRUCTIONS** 1. Prepare the airplane for maintenance. A. Make sure that all switches are in the OFF/NORM position. B. Disconnect electrical power from the airplane. (1) Disconnect the airplane batteries. (2) Disconnect external electrical power. C. Attach maintenance warning tags to the batteries and external power receptacle that have **"DO NOT CONNECT ELECTRICAL POWER - MAINTENANCE IN PROGRESS"**  written on them. 2. Get access to the aft J-Box. A. Remove the access panels 311ABC. (Refer to the Model 680 Maintenance Manual, Chapter 6, Access Plates And Panels Identification - Description And Operation.) B. Remove the covers from the left and right J-Box.

# Citation 

# SERVICE BULLETIN **SB680-24-11** 3. Get access to the left and right relay rack. A. (Refer to Figure 1, Views D-D and E-E.) Remove and keep the two inboard retaining screws from the left and right circuit breaker panel to access the relay racks. B. Remove the left relay rack and keep the screws. C. Remove the right relay rack and keep the screws. 4. (Refer to Figure 2, Sheet 1 and Sheet 2.) Install the diodes to the left and right motive flow relays. (Refer to the Model 680 Wiring Diagram Manual, Chapter 20, Wiring - Maintenance Practices.) **NOTE:** The 1N4006 Diodes must be installed properly or the operational check will fail. 5. Install the left and right relay rack with the kept screws. 6. Install the inboard retaining screws that were kept in the left and right circuit breaker panels. 7. Prepare the airplane for power. A. Remove maintenance warning tags from the batteries and external power receptacle. B. Make sure that all switches are in the OFF/NORM position. C. Connect electrical power to the airplane. (1) Connect the airplane batteries. (2) Connect external electrical power. 8. Do an operational check of the fuel cross feed. A. Power the airplane on. B. Place the Left electrical bus in EMER. C. Cyan FUEL CROSS FEED & FUEL BOOST PUMP ON R CAS messages should not appear. D. Return the Left electrical bus to normal. E. Place the Right electrical bus in EMER. F. Amber FUEL CROSS FEED TRANSIT & Cyan FUEL BOOST PUMP ON L CAS messages should not appear. G. Return the Right electrical bus to normal. H. Turn the CROSSFEED switch to R TANK to L ENG. I. A Cyan or Amber CAS message for FUEL CROSS FEED and FUEL BOOST PUMP ON R should appear. **NOTE:** An Amber CAS message will only be present if cross feeding from the tank with less fuel. J. An amber FUEL MOTIVE VLV FAIL L Fail message should not appear. K. Turn the CROSSFEED switch to off. L. Turn the CROSSFEED switch to L TANK to R ENG. M. A Cyan or Amber CAS message for FUEL CROSS FEED and FUEL BOOST PUMP ON L should appear. **NOTE:** An Amber CAS message will only be present if cross feeding from the tank with less fuel. N. An amber FUEL MOTIVE VLV FAIL R CAS message should not appear. O. Turn the CROSSFEED switch to off. P. Turn airplane power off. 9. Disconnect external electrical power. Dec 16/2010 680-24-11 Revision 1 - Nov 15/2011 Page 3Dec 16/2010 680-24-11 Revision 1 - Nov 15/2011 Page 4 

# Citation 

# SERVICE BULLETIN **SB680-24-11** 10. Disconnect the airplane batteries. 11. Install the J-Box covers. 12. Install the access panels that were removed. (Refer to the Model 680 Maintenance Manual, Chapter 6, Access Plates And Panels Identification - Description And Operation.) 13. Update the 680 FAA Approved Airplane Flight Manual (68FM). A. For Airplanes that use the 680 FAA Approved Airplane Flight Manual (68FM-09) (1) Make sure that Temporary Changes 68FM TC-R09-09, 68FM TC-R09-10, 68FM TC-R09-11, and 68FM TC-R09-12 are removed from the 680 FAA Approved Airplane Flight Manual (68FM-09). (2) Make sure that Temporary Change 68FM TC-R09-13 is inserted into the 680 FAA Approved Airplane Flight Manual (68FM-09). B. For Airplanes that use the 680 FAA Approved Airplane Flight Manual (68FM-10) (1) Make sure that Temporary Changes 68FM TC-R10-01, 68FM TC-R10-02, and 68FM TC-R10-03 are removed from the 680 FAA Approved Airplane Flight Manual (68FM-10). **NOTE:** The intent of 68FM TC-R09-13 has been incorporated in 68FM-10. 14. Record that this service bulletin has been completed. A. Complete a Maintenance Transaction Report. B. Put a copy of th e completed Maintenance Transaction Report in the airplane logbook. C. Send a copy of the completed Maintenance Transaction Report to: CESCOM C/O Camp Systems International, 8200 East 34th Street North, Building 1600 Suite 1607 Wichita, KS 67226.

**MATERIAL INFO RMATION**  Order the kit below to install this modification.

**NEW P/N QUAN TITY**  **KEY WORD OLD P/N INSTRUCTIONS/ DISPOSITION**  **SB680-24-11** 1 **Kit,** consisting of the following parts: D436-0098 2 Sleeve D609-04 4 Splice 1N4006 2 Diode SB680-24-11 1 Instructions

# Citation 

# SERVICE BULLETIN **SB680-24-11**

Figure 1. Fuel Crossfeed Improvement (Sheet 1)

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# Citation 

# SERVICE BULLETIN **SB680-24-11**

Figure 1. Fuel Crossfeed Improvement (Sheet 2)

# Citation 

# SERVICE BULLETIN **SB680-24-11**

Figure 1. Fuel Crossfeed Improvement (Sheet 3)

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# Citation 

# SERVICE BULLETIN **SB680-24-11**

Figure 2. Fuel Crossfeed Improvement (Sheet 1)

# Citation 

# SERVICE BULLETIN **SB680-24-11**

Figure 2. Fuel Crossfeed Improvement (Sheet 2)

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