# MODIFICATION KIT

# ~ CesSna ATextroneom;nv 

# Single Engine

MK172-28-01

TITLE ENGINE FUEL RETURN SYSTEM INSTALLATION
EFFECTIVITY

DESCRIPTION Model 172R 172S Serial Numbers 17280001 thru 17281187 172S8001 thru 172S9490

To provide parts and instructionsto installthefuel return system modification.
APPROVAL FAA approval has been obtained on technical data in this publication that affects airplane type design.
REFERENCE SB04-28-03 CHANGE IN WEIGHT AND BALANCE

Model

............................. . Weight Change

...................... . ARM

............................. . Resultant Moment

. . . . . . . . . . . . . . . . . . . . . Moment/1000

August 30, 2004 172R/172S +1.0 Pound 

### 0 0 0

Page 1 of 9 To obtain satisfactory results, procedures specified in this publication must be accomplished in accordance with accepted methods and prevailing government regulations. CessnaAircraft Company cannot be responsible for the qualityofwork performed in accomplishing the requirements ofthis publication. Cessna AircraftCompany, Product Support, P.O. Box 7706, Wichita, Kansas 67277, U.S.A. (316) 517-5800, Facsimile (316) 942-9006 COPYRIGHT© 2004MATERIAL INFORMATION 

### The following parts will be necessary:

NEW P/N QUANTITY DESCRIPTION OLD P/N DISPOSITION 

### MK172-28-01 1 Kit, 

### consisting of the following parts: AE3663163E0240 1 Hose Assembly None None AN832-4 Union None None AN924-4 1 Nut None None MS21062L3 1 Nut None None MS2191WDG5 1 Clamp None None MS21929WDG10 1 Clamp None None MS35207-264 Screw None None NAS1149F0332P 1 Washer None None MS29512-04 1 0-Ring MS29512-04 Discard S2218-4 1 Check Valve None None 02G22973 1 Orificed Fitting Existing Plug Discard 0500118-49 Line Assembly None None 0500118-53 Line Assembly None None 0516009-24 1 Fuel ReservoirAssembly 0516009-18 Discard MK172-28-01 Instructions In addition tothe MK172-28-01 Kit, thefollowing (or later revision) will be necessary.

Part Number Description 

### 172RPHUSR09 Revision 9, Modei172R (See Note) Pilot's Operating Handbook 172SPHUSR05 Revision 5, Modei172S (See Note) Pilot's Operating Handbook 172R180PHUSR03 Revision 3, Model 172R 180HP (See Note) Pilot's Operating Handbook NOTE: 

### This revision has been sentto applicable airplane owners of record. Referto SB04-11-02for detailed information. ACCOMPLISHMENT INSTRUCTIONS 

### 1 . Electricallygroundthe airplane and turn all switchesto the "OFF" position. If external power is connected to the airplane, disconnect external powerfrom receptacle. 2. Disconnectthe airplane battery. (Referto the Model 172 Series 1996and On Maintenance Manual, Chapter24, Electrical Power.) 3. Attach maintenance warning tags to the battery and external power receptacle with the following instruction: DO NOT CONNECT ELECTRICAL POWER - MAINTENANCE IN PROGRESS. 

### 4. Remove the upperand lower engine cowls. (Referto the Model 172 Series 1996 and On Maintenance Manual, Chapter 71, Powerplant.) MK172-28-01 Page2

### WARNING: DURING ALL FUEL SYSTEM SERVICING PROCEDURES, FIRE FIGHTING EQUIPMENT MUST BE AVAILABLE. TWO GROUND WIRES FROM TIE DOWN RINGS ON THE AIRPLANE TO APPROVED GROUND STAKES SHALL BE USED IN CASE OF ACCIDENTAL DISCONNECTION OF ONE GROUND WIRE. 5. Defuel the airplane. (Refertothe Model 172 Series 1996and On Maintenance Manual, Fuel
- Servicing.) 6. Remove the copilotseatand carpet. (Referto Chapter25, Front Seatsand Rails
- Maintenance Practices and Chapter25, Interior Upholstery- Maintenance Practices.) A. Remove the copilot side 0515075-40 Panel to getto the fuel reservoir assembly. B. Remove the copilot side 0513512-9 Forward Floorboard and the access panel behind the rudder pedalsto get to the fuel reservoir. 7. (Referto Figure 1.) Remove the safetywire and plug in the forward top side ofthe fuel servo and install a 02G22973 Orificed Fitting with a MS29512-04 0-Ring. 

### CAUTION: INSTALLA PROTECTIVE CAP ON THE ORIFICED FITTING UNTILTHE HOSE IS INSTALLED TO THE FITTING. 

### CAUTION: BEFORE YOU DRILL INTOTHE FIREWALL, MAKE SURE THATTHE AREA BEHIND THE FIREWALL, WHERE THE NEW HOLE WILL BE DRILLED, IS CLEAR OF ANY AIRPLANE STRUCTURE OR ANY OTHER ITEMS THAT MAY PREVENTTHE INSTALLATION OFTHE NEW FUEL LINE AND FITTINGS. 8. (Referto Figure 2, Sheet 1 and 2.) Drill 0.438 inch diameterfuel return hole in thefirewall as shown. 9. (Referto Figure 3, Sheet2.) Install a AN832-4 Union, NAS1149F0932P Washer, and AN924-4 Nut in the firewall fuel return hole as shown. 10. (Referto Figure 1, View A-A.) Install a AE3663163E0240 HoseAssembly betweenthe fuel servo orificed fitting and the firewall AN832-4 Union. A. Remove the protective cap on the 02G22973 Orificed Fitting installed in Step 7 and install the AE3663163E0240 HoseAssembly nuttothe orificedfitting. Leave the nut loose until the hose is positioned and clamped to the brace as shown. NOTE: The AE3663163E0240 HoseAssembly must be in a relaxed and smooth position before the nuts are tightened. B. Install the other end ofthe AE3663163E0240 Hose Assembly nutto the firewall AN832-4 Union. Leave the nut loose until the hose is positioned and clamped tothe brace as shown. C. Attach theAE3663163E0240 Hose Assemblyto the 0750625-4 Bracewith clamps and hardware as shown. D. Tighten the AE3663163E0240 HoseAssembly nuts but make sure it is in a relaxed and smooth condition afterthe nuts are tightened. 11. (Referto Figure 3, Sheet 1.) Install the 0500118-49 Line Assembly from the aft side of the firewall AN832-4 Union to the S2218-4 Check Valve. Install the S2218-4 Check Valve and make sure the check valve flow arrow points to the reservoir. 

### WARNING: BEFORE THE FUEL RESERVOIR IS REMOVED, MAKE SURE TO DRAIN THE FUEL FROM THE SUMP DRAIN ON THE RESERVOIR TO KEEP FUEL SPILLAGE TO A MINIMUM. 12. Remove the 0516009-18 Fuel Reservoir Assemblythat is installed in the airplane, keep all hardware. (Refertothe Model 172Series 1996and On Maintenance Manual, Chapter28, Storage and DistributionMaintenance Practices.) 13. Install a new 0516009-24 Fuel ReservoirAssembly into the airplanewith the kept hardware. MK172-28-01 Page3**-----~-~-----------------------** -**--------------------~-------------- ------~--**  ---

14. Install a new0500118-53 Line Assemblyfrom the aft end of the S2218-4 Check Valve to the new 0516009-24 Fuel ReservoirAssembly. (Refertothe Model172 Series 1996and On Maintenance Manual, Chapter28, Storage and Distribution- Maintenance Practices.) 15. Fuel the airplane and do a fuel leak inspection. 16. Install the floorboards and the side panels removed in Step 6. 

### CAUTION: MAKE SURETHE ATTACH SCREWS DO NOTTOUCH THE NEW INSTALLED FUEL LINE WHEN THE FLOORBOARDS AND ACCESS PANELS ARE INSTALLED. 17. Install the copilot's seat and carpet. (Referto Chapter25, Front Seats and Rails
- Maintenance Practices and Chapter25, Interior Upholstery- Maintenance Practices.) 18. Reconnect the airplane battery. (Referto the Model 172 Series 1996and On Maintenance Manual, Chapter24, Electrical Power.) 19. Install the upperand lowerengine cowls. (Refertothe Model 172 Series 1996 and On Maintenance Manual, Chapter71, Powerplant.) 20. Remove maintenance warning tags from battery and external power receptacle. 21. (Refertothe Pilot's Operating Handbook) Do a "beforetakeoff engine operation check". 22. Putthe applicable revision intothe Pilot's Operating Handbook if it has not previously been incorporated. 

### NOTE: Model 172R Pilot's Operating Handbookand FAA Approved Airplane Flight Manual, Revision 9, or latest revision. Model 172S Pilot's Operating Handbook and FAAApproved Airplane Flight Manual, Revision 5, or latest revision. Model 172R 180HP Pilot's Operating Handbook and FAA Approved Airplane Flight Manual, Revision 3, or latest revision. 23. Make an entry in the airplane logbookthat statesthis Modification Kit has been installed.

MK172-28-01 Page4MK172-28-01 02G22973 ORIFICED FITTING (1 REQUIRED) FUEL SERVO (REFERENCE) FIRE WALL (REFERENCE) 

### I 

# -------i

-- I

BRACE (REFERENCE)
VIEW 

# A-A MS21919WDG5 CLAMP MS21919WDG10 CLAMP MS35207-264 SCREW I MS2102L3

NUT NAS1149F0332P WASHER (1 EACH REQUIRED)

AN832-4 UNION (REFERENCE)

AE3663163E0240 HOSE ASSEMBLY (1 REQUIRED)
0510T1007 AA0550T359 Figure 1

. Fuel Return System Installation (Sheet 1)

Page5FIREWALL (REFERENCE)



### Page6 

### DETAIL 

# A Figure 2. Fuel Return Firewall Hole Installation (Sheet 1) 0510T1007 A0511T1008



### MK172-28-0183770



### FUEL STRAINER BRACKETS (REFERENCE) 0.438 INCH DIAMETER FUEL RETURN HOLE (NOTE) 

# +

/ / 

### CENTER LINE 

# +

®·---®


# +

NOTE: 

### LOWER FIREWALL;/' VIEW 

## A-A 

# j.-- 4.28 INCHES

# -----.J

DOUBLER FLANGE LOOKING AFT (REFERENCE) LOWER FIREWALLASSEMBLY

DRILL A 0.438 INCH DIAMETER HOLE IN THE LOCATION SHOWN AND MAKE SURE YOU DO NOT DRILL INTOANY OBSTRUCTIONS OR STRUCTURE ON THE AFT SIDE OF FIREWALL. 0553T031 

### Figure 2. Fuel Return Firewall Hole Installation (Sheet 2)

MK172-28-01 Page?

# ( A

PageS 

# A

FUEL RESERVOIR (REFERENCE) 

# /f A

DETAIL 

# A BEFORE FUEL RETURN MODIFICATION


### Figure 3. Fuel Return to Reservoir Installation (Sheet 1) 0510T1007 A0516T1007



### MK172-28-0183772

FUEL STRAINER (REFERENCE)

AE3663163E0240 HOSEASSEMBLY (REFERENCE)

AN832-4 UNION FIREWALL (REFERENCE)FUEL SHUTOFF VALVE (REFERENCE) ELECTRICAL FUEL PUMP (REFERENCE)

AN924-4 0500118-49 NUT LINE 0516009-24 FUEL RESERVOIR ASSEMBLY (1 REQUIRED)

(1 REQUIRED) AN960-916L ASSEMBLY S2218-4 CHECKVALVE (1 REQUIRED)

MK172-28-01 WASHER 

### (1 REQUIRED) (1 EACH REQUIRED)

# ~FWD VIEW 

# A-A LOOKING DOWN AFTER FUEL RETURN MODIFICATION

Figure 3. Fuel Return to Reservoir Installation (Sheet 2) 050018-53 LINE ASSEMBLY (1 REQUIRED

0516T015DCN0498

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