TITLE LANDING GEAR - NOSE LANDING GEAR STRUT SEAL IMPROVEMENT EFFECTIVITY MODEL SERIAL NUMBERS 680 ( Sovereign) -0001 thru -0265, -0267 thru -0271, -0273 thru -0290 REASON The equivalent of this service letter has been incorporated on production airplanes -0266, -0272, -0287, -0291 and On. To inform operators of a Nose Landing Gear Strut Seal improvement and describe the subsequent part-marking, part numbering and record keeping requirements. DESCRIPTION This document contains instructions and illustrations required to install improved seal assemblies in the Nose Landing Gear Strut. It also provides instructions for the subsequent part marking, part numbering and record keeping requirements. The parts required to be removed and installed for this improvement are based on the part number configuration of the NLG Assembly prior to modification as follows: 6742160-4 NLG Assembly and the 6742160-7 NLG Assembly will use parts contained in the 6742160-210 Seal Modification kit. 6742160-8 NLG Assembly will use parts contained in the 6742160-200 Seal Modification kit. COMPLIANCE INFORMATIONAL. This service letter is for informational purposes only. MANPOWER WORK PHASE Modification MAN-HOURS As Necessary REFERENCES Cessna Model 680 Component Maintenance Manual PUBLICATIONS AFFECTED Cessna Model 680 Component Maintenance Manual Page 1 of 5 Cessna Aircraft Company, Marketing Division, P.O. Box 7706, Wichita, KS 67277, U.S.A. 1-316-517-6000, Fax 1-316-517-8500 COPYRIGHT 2009
ACCOMPLISHMENT INSTRUCTIONS CAUTION: Remove and discard the original parts before unwrapping any new parts. Old and new parts will look identical. 1. Do an inspection of the serial number on the Nose Landing Gear components. A. If the upper and/or lower barrel serial numbers have an M suffix, go to Step 7. B. If the upper and/or lower barrel serial numbers do not have an M suffix, go to Step 2, 3, or 4, as necessary for your NLG assembly part number. 2. (Refer to Figure 1, Detail A) For the 6742160-4 NLG Assemblies, order the 6742160-210 Special Spare Seal Modification Kit that contain the following detail parts: A. 6742184-2 Isolation Piston B. 6742172-6 Retainer Nut C. 6742172-5 Retainer Spacer D. 7332MRE964P20 Isolation Piston Seal E. 7337FRE964P20 Retainer Nut Seal 3. (Refer to Figure 2, Detail A) For the 6742160-7 NLG Assemblies, order the 6742160-210 Special Spare Seal Modification Kit that contain the following detail parts: A. 6742184-2 Isolation Piston B. 6742172-6 Retainer Nut C. 6742172-5 Retainer Spacer D. 7332MRE964P20 Isolation Piston Seal E. 7337FRE964P20 Retainer Nut Seal 4. (Refer to Figure 3, Detail A) For the 6742160-8 NLG Assemblies, order the 6742160-200 Special Spare Seal Modification Kit that contain the following detail parts: A. 6742184-2 Isolation Piston B. 6742172-6 Retainer Nut C. 7332MRE964P20 Isolation Piston Seal D. 7337FRE964P20 Retainer Nut Seal 5. Use the steps in the Model 680 Component Maintenance Manual, Nose Landing Gear Assembly section, for instructions to remove and install NLG strut and seal components. 6. Add an M as a suffix on the individual gear component placards to reflect that the 6742160-200 or the 6742160-210 NLG Special Spare Seal modification has been incorporated. NOTE: Do not change the 6742160-4, 6742160-7 and 6742160-8, NLG Assembly part number after the spare solution is accomplished. 7. Record that this service letter has been completed. A. Complete a Maintenance Transaction Report. B. Put a copy of the completed Maintenance Transaction Report in the airplane logbook. C. Send a copy of the completed Maintenance Transaction Report to: CESCOM, P.O. Box 7706, Wichita, KS 67277. Page 2
Figure 1. Nose Landing Gear Strut Seal Improvement - 6742160-4 NLG Assemby (Sheet 1) Page 3
Figure 2. Nose Landing Gear Strut Seal Improvement - 6742160-7 NLG Assembly (Sheet 1) Page 4
Figure 3. Nose Landing Gear Strut Seal Improvement - 6742160-8 NLG Assembly (Sheet 1) Page 5