# Single Engine **Service Bulletin** January 29, 2007 SB07-79-01

**TITLE** ENGINE OIL PR ESSURE SWITCH REPLACEMENT **EFFECTIVITY Model Serial Numbers**  172R 17280001 thru 17281272 172S 172S8001 thru 172S10102 182S 18280001 thru 18280944 182T 18280945 thru 18281741 T182T T18208001 thru T18208480 206H 20608001 thru 20608257 T206H T20608001 thru T20608585

**REASON** Analysis of the wear on the internal parts of the part number 83278 oil pressure switch reveals the need to establish a life limit of 3000 hours of operation for the switch. Too much wear of the internal parts of the switch may lead to oil leakage from the switch. **DESCRIPTION** The time in service of the part number 83278 oil pressure switch shall be determined and the switch shall be replaced when it reaches 3000 hours of operation. **COMPLIANCE** Mandatory: the part number 83278 oil pressure switch shall be replaced every 3000 hours of operation. A one time inspection to determine the time in service of the engine oil pressure switch shall be accomplished at the next oil change or within the next 50 hours of operation, whichever occurs fi rst. Subsequent Inspections: oil pressure switch life limit replacement shall be accomplished in accordance with the Component Time Limits Section of the applicable airplane Maintenance Manual (latest revision). **APPROVAL** FAA approval has been obtained on technical data in this publication that affects airplane type design. Page 1 of 4 To obtain satisfactory results, procedures speci fi ed in this publication must be accomplished in accordance with accepted methods and prevailing government regulations. Cessna Aircraft Company cannot be responsible for the quality of work performed in accomplishing the requirements of this publication. **Cessna Aircraft Company** , Product Support, P.O. Box 7706, Wichita, Kansas 67277, U.S.A. (316) 517-5800, Facsimile (316) 942-9006 COPYRIGHT © 2007**MANPOWER** Approximately 0.5 man-hour when accomplished concurrent with an oil change. **REFERENCES** Model 172 Series 1996 and On Maintenance Manual Model 182/T182 Series 1997 and On Maintenance Manual Model 206/T206 Series 1998 and On Maintenance Manual **NOTE:** Make sure all publications used are complete and current. **NOTE:** This information shall be considered an amendment to the Cessna Manufacturer's Service/Maintenance Manual or Instructions for continued airworthiness and must be accomplished for ongoing airworthiness compliance as required per 14 CFR Part 43.13. **MATERIAL PRICE AND AVAILABILITY** The parts below are available from Cessna Parts Distribution through an appropriate Cessna Service Station for the suggested list price shown.

**P a**  **r t**  **N u**  **m b**  **e r**  **D e**  **s c**  **r i**  **p t**  **i o**  **n Q** **t y**  **/ A**  **i r**  **p l**  **a n**  **e P**  **r i**  **c e**  83278 Switch, Oil Pressure 1 $ 43.30 (PS) ea U544006S Sealant, Thread (Loctite 592, 1.69 fl . oz.) (as required) $ 49.00 (VO) ea

ALL PRICES SUBJECT TO CHANGE WITHOUT NOTICE
**CREDIT INFORMATION** Not applicable **ACCOMPLISHMENT INSTRUCTIONS Weight And Balance Information**  Negligible. **Material Information** The part below may be necessary:

**NEW P/N QUANTITY DESCRIPTION OLD P/N DISPOSITION** 83278 1 Switch, Oil Pressure 83278 Discard

The material that follows, or equivalent, is necessary:

**NAME NUMBER MANUFACTURER USE**  Loctite 592 - Thread Sealant U544006S Cessna Aircraft Company Cessna Parts Distribution 5800 East Pawnee PO Box 1521 Wichita, KS 67218 To apply to the threads of the switch

SB07-79-01 Page 2 January 29, 2007**Instructions** 1. Review applicable airplane paperwork. Find the number of hours of operation of the 83278 Oil Pressure Switch that is installed on your airplane. A. If the 83278 Oil Pressure Switch has 3000 hours or more of operation, you must replace it. Go to Step 2. B. If the 83278 Oil Pressure Switch has less than 3000 hours of operation, it is not necessary to replace it at this time. You must monitor the hours of operation of the switch, and replace it at or before 3000 hours of operation. Go to Step 8. 2. 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 battery. (2) Disconnect external electrical power. C. Attach maintenance warning tags to the battery and external power receptacle that have **"DO NOT CONNECT ELECTRICAL POWER - MAINTENANCE IN PROGRESS"**  wri tten on them. 3. Remove the used 83278 Oil Pressure Switch. (Refer to the applicable Maintenance Manual, Chapter 79, Oil Pressure Indicator - Maintenance Practices.) 4. Install the new 83278 Oil Pressure Switch. (Refer to the applicable Maintenance Manual, Chapter 79, Oil Pressure Indicator - Maintenance Practices.) 5. Remove the maintenance warning tags from battery and external power receptacle. 6. Reconnect the airplane battery. (Refer to the applicable Maintenance Manual, Chapter 24, Electrical Power.) 7. Do an oil pressure switch operational test as follows. A. Turn on the master switch and make sure that the low oil pressure warning annunciator is on. B. Start the engine. (Refer to the applicable Pilot's Operating Handbook, Section 4, Normal Procedures - Starting Engine.) C. Operate the engine until the oil pressure goes into the normal operating range. (1) Make sure that the low oil pressure warning annunciator goes off. D. Make sure that the hour meter operates correctly. E. Stop the engine. (Refer to the applicable Pilot's Operating Handbook, Section 4, Normal Procedures - Securing Engine.) F. Do a check for oil leaks at the oil pressure switch installation. 8. Make an entry in the airplane logbook that states compliance and method of compliance with this Service Bulletin. If you did not replace the oil pressure switch, record the current time in service hours of the installed switch. SB07-79-01 January 29, 2007 Page 3**OWNER NOTIFICA TION**  On January 29, 2007 the following message will be sent to applicable owners of record in SB07-79-01A. Dear Cessna Owner: This Owner Adv isory is to inform you that SB07-79-01 has been issued. Analysis of the wear on the internal parts of the part number 83278 oil pressure switch reveals the need to establish a li fe limit of 3000 hours of operation for the switch. Too much wear of the internal parts of the switch may lead to oil leakage from the switch. The time in service of the part number 83278 oil pressure switch shall be determined and the switch shall be replaced when it reaches 3000 hours of operation. Compliance is mandatory: the part number 83278 oil pressure switch shall be replaced every 3000 hours of operation. A one time ins pection to determine the time in service of the engine oil pressure switch shall be accomplished at the next oil change or within the next 50 hours of operation, whichever occurs fi rst. Subsequent I nspections: oil pressure switch life limit replacement shall be accomplished in accordance with the Component Time Limits Section of the applicable airplane Maintenance Manual (latest revision). The informat ion contained in the referenced Cessna Service Bulletin shall be considered an amendment to the Cessna Manufacturer's Service/Maintenance Manual or Instructions for continued airworthiness, and must be accomplished for ongoing airworthiness compliance as required per 14 CFR Part 43.13. Please contact a Cessna Single Engine Service Station for detailed information and arrange to have Cessna Service Bulletin SB07-79-01 accomplished on your airplane.

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SB07-79-01 Page 4 January 29, 2007