I NOTE I I NOTE 1. g. Touch up housing surfaces (HMI Appendix D), as requjred, to prevent corrosion. Models 269A, TH-55A, A-1, B & C - Basic HMI

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1 Section 10 Models 269A, TH-55A, A-1, B & C - Basic HM MANTENANCE OF MAN TRANSMSSON. Maintenance of the main transmission and components thereof must be accomplished in accordance HM Appendix C, Part NSTALLATON OF MAN TRANSMSSON. Refer to Figures 10-1 and 10-6 for torque specifications of main transmission attach hardware. a. b. C. d. e. f. NOTE 1 Lubricate tachometer cable with grease (Table 2-2, tem 39) before attaching to main transmission. nstall main transmission, reversing the order (and logic) of procedure outlined for removal (Pa ragrap h 10-16). Fill transmission with approved lubricant in accordance with Section 2. Pressurize lubrication system by turning main rotor 10 or more times, and inspect for oil leakage at seals. Verify proper installation of gasket between transmission and mast by removing jet from main rotor mast and pressurize lubrication system by rotating main rotor blades. Observe the open port as the blades are rotated. (Oil should flow out of port as blades are rotated.) Lack of oil flow through the open port indicates that the gasket between the upper housing and the main rotor mast has been incorrectly installed and is blocking oil flow to the upper bearing. After attachment of tachometer cable, rotate transmission and check for binding of cable. nspect entire assembly for security of electrical component connections, lockwiring, etc. Unpainted surfaces on the magnesium housings of main transmission are extremely susceptible to corrosion. g. Touch up housing surfaces (HM Appendix D), as requjred, to prevent corrosion BELT DRVE CLUTCH CONTROL NSTALLATON GENERAL. The belt drive clutch control installation (Figure 10-7) consists of a linear actuator, electrical connections to a CLUTCH control switch and to a warning light on the instrument panel (Section 14), and a cable and pulley to interconnect the linear actuator to the clutch spring on the belt drive transmission. When the CLUTCH control switch on the instrument panel is at the ENGAGE position, the linear actuator retracts, applying tension to the idler pulley. The idler pulley moves outboard and applies tension to the main rotor drive V-belts to transfer power from the engine to the main transmission and the tail rotor. The clutch warning light is on when the clutch is disengaged and during engagement and goes out when the clutch is fully engaged. A safety circuit cuts off electrical power to the start relay unless the clutch is.in the DSENGAGED position. Observe the following notes whenever maintenance is performed on the belt drive clutch control installation: For information on a manually operated belt drive clutch control installation, refer to HM Configuration Supplement A/A-1. Two styles of clutch control spring assemblies are authorized for service on 269 Series Helicopters. Early style spring assemblies incorporate an inner spring guide which retains the cable end terminal at the upper portion of the guide. Later style spring assemblies incorporate an improved inner spring guide which allows the cable to seat at the bottom of the guide (Figure 10-8). As a result, the possibility of chafing and cable wear due to contact with the inner spring guide is significantly reduced when a later style clutch control spring assembly is installed. Refer to N-226 for additional information Revised: 19 Feb 1996

2 Models 269A, TH-55A A-1, B & C - Basic HM Section 10 Revised: 19 Feb 1996 Figure Belt Drive Clutch Control nstallation (Sheet 1 of 3)

3 Models 269A, TH-55A, A-1, B & C - Basic HM Section 10 SPRNG FTTNG -, VEDFROM NUT SDE, THREADS SHALL EXTEND NTO HOLE PRlNG FTTNG DETAL C,010 TO,020 N. i~ DETAL "8' DETAL c (TYPCAL EXAMPLE) OVERALL : E N G T H ' T i c-.l THERMOFT TUBE \ SPRNG RETANER SPRNG RETANER OVERALL LENGTH A B 6.35 NCH.10/ REF 6.53 NCH, REF C SOl Revised: 19 Feb 1996 Figure Belt Drive Clutch Control nstallation (Sheet 3 of 3)

4 Models 269A, TH-55A, A-1, B & C - Basic HM Section REMOVAL OF BELT DRVE CLUTCH, CONTROL NSTALLATON. (Figure 10-7.) a. Place BAT switch to ON position. b. Place CLUTCH control switch to RELEASE position. Tension on clutch control rigging cable should now be released. f tension is not released, troubleshoot clutch control circuit. c. Place BAT switch to OFF position. d. Disconnect electrical connector from linear actuator. Service Bulletin requires replacement of clevis pins with bolts in the clutch control installation. f not already accomplished, the clevis pins should replaced with bolts as part of the removal/inspection/installation procedure. The necessary steps for bolt installation are provided in Paragraph e. Remove cotter pin, nut, washers, and bolt (or clevis pin) attaching linear actuator to center section frame fitting. f. Remove two guard pins from pulley brackets. g. Remove cotter pin, nut, washer, and bolt attaching pulley to brackets. Remove pulley. h. Remove cotter pin, nut, washer, and bolt (or small clevis pin) from dual attachment strap (Figure 10-7, Sheet 2). i. Remove linear actuator, clutch control cable and spring assembly PERODC NSPECTON OF BELT DRVE CLUTCH CONTROL ENGAGEMENT CABLE. (Figure 10-7.) Wear and fretting of the cable can occur during normal operation and a cursory inspection of the assembly will not reveal damage. nspect the cable and attaching fittings closely at every 50-Hour nspcction (steps a. through d.). Perform disassembled inspection (step e.) and Revised: 1 April 1994 end terminal inspection (step f.) at intervals specified in HM Appendix B. a. Place BAT switch to ON position. b. Place CLUTCH control switch to RELEASE position. NOTE Tension on clutch control cable should now be released. f tension is not released, troubleshoot the clutch control circuit before continuing with the following inspections. e. Place BAT switch to OFF position. d. nspect entire exposed length of clutch engagement cable as follows: Be sure to check the first 8 inches of cable directly below clutch spring assembly. (1) Check for dirt accumulation (clean as required), excessive wear and fraying. (2) Check for evidence of corrosion and bums. (Replace cable if corrosion is noted.) (3) Check for broken cable strands (none allowed). (4) Check for tightness and damage of swaged fittings (end ball and end terminal). (5) Check for security of turnbuckle and lockwire (or locking clip). NOTE 1 Replace cable for any broken strands or if excessive wear is evident. e. Perform the following disassembled inspection at the intervals specified in HM Appendix B. (Refer to Figure 10-7, Sheet 2 for part locations.) (1) Ensure that clutch control cable tension is released (steps a. through c., above)

5 Models 269A, TH-55Al A-1 B & C - Basic HM Section 10 CAUTON The two distances measured in the preceding step should be within inch of one another. F the distances are not within these limits, the cable must be replaced. Do not attempt to straighten cables that do not meet the criteria. Straightening cables could induce further fatigue and failure. (6) Rotate cable in 60' intervals and repeat step (5) at each interval, until measurements have been made at each 60' interval. NOTE 1 Apply a small amount of rubber cement (Table 2-2, tem 80) to rubber cap before inserting in spring retainer. Cap should be approximately flush with end of retainer. g. Reassemble in reverse order of disassembly install bolts in dual attachment strap, fitting, and spring housing (Figure 10-7, Sheet 2) in accordance with applicable steps of Paragraph h. After reassembly is complete, check for appropriate clearance through full range of cable movement; adjust cable tension in accordance with Paragraph NSTALLATON AND ADJUSTMENT OF BELT DRVE CLUTCH CONTROL NSTALLATON. (Figure 10-7.) The dual attachment strap must be attached to the idler pulley attachment tube (Figure 10-14) and the inner washers should be cemented to the inner faces of the strap (Figure 10-7, Sheet 2). CAUTON 1 MS17826 nuts are self locking and castellated for double safety, and must be used in steps a., d., and e. below. Do not torque nuts; all joints must be free to swivel after hardware is installed. A slightly longer or shorter bolt is permissible provided the conditions specified in the steps are satisfied. a. Align spring assembly fitting with dual attachment strap. nstall specified hardware (Figure 10-7, NOTE 11) in accordance with steps (1) and (2) below. (1) nstall bolt with a minimum of one washer at nut end. Verify that bearing surfaces DO NOT contact bolt threads (Figure 10-7, Sheet 3). (2) nstall nut and align castellation with cotter pin hole in bolt (nut should not bottom out on bolt threads). To be sure joint is free, check for to inch axial play in bolt; add washer(s) at nut end only if required. nstall cotter pin. b. Position cable pulley in brackets and install attachment bolt, washer, nut and cotter pin. nstall cable assembly on pulley. c. nstall two guard pins in pulley brackets. (Ensure that cable is positioned between pulley and guard pins.) d. Position actuator lug on center section frame fitting. nstall specified hardware (Figure 10-7, NOTE 4) in accordance with steps a.(l) and a.(2) above. Attach electrical connector to linear actuator. e. f applicable, perform steps (1) through (3) below. (nstall hardware in accordance with steps a.(l) and a.(2) above.) (1) Remove large clevis pin from spring housing and replace with specified hardware (Figure 10-7, NOTE 12). Revised: 1 April

6 Models 269A, TH-55A, A-1, B & C - Basic HM Section 10 (b) Using heat gun or equivalent, apply heat as necessary to firmly shrink thermofit tube on spring retainer. Avoid excessive heating that can result in rupture of t hermo fit tube. (c) Carefully trim thermofit tube to required dimensions; do not damage spring retainer surface (Figure 10-7, Sheet 3, Detail D). d. nstallation of Spring Retainer. nstall spring retainer and reassemble clutch control spring assembly in reverse order of disassembly, and in accordance with the following. CAUTON i Verify that rivet holes in spring end and spring retainer are correct size before installing rivets. A inch hole is required for driven rivet P/N MS20470AD4; a inch hole is required for blind rivet P/N NAS1738B4-2. f driven rivets were previously installed, the rivet holes may be modified (if desired) to accommodate the blind rivets. n this event, perform step (2) instead of step (1). (1) Carefully compress the tension control spring (Figure 10-7) and install spring end on spring retainer using MS20470AD4 or NAS1738B4-2 rivets, as applicable. (2) To convert to blind rivets, modify spring end (Figure 10-7) as follows: Enlarge four rivet holes to inch using #27 drill. Spotface rivet holes to inch diameter, inch deep. Carefully compress the tension control spring and install modified spring end on spring retainer using NAS1738B4-2 rivets. (3) Prior to installation of inner spring guide, verify that rivets (installed in step (1) or (2) above) will not interfere with movement of inner spring guide. After installation of rivets, maintain diameter clearance; concentric within to.d. of tube. A inch diameter shaft (fabricated locally) should be inserted inside the spring end to check for this condition. For old style configurations, where hole in spring end is not large enough to allow cable removal, it will be necessary to cut a longitudinal slot in fabricated shaft in order to check condition specified in step (3). e. Reassemble remaining components of clu :h control spring assembly in reverse order of disassembly. f. nstall and adjust the belt drive clutch control installation in accordance with Paragraph LNEAR ACTUATOR GENERAL. The linear actuator is a motorized electrically operated unit. The actuator is driven by a simple electrical motor (12- or 24-volt) with an armature that is wound in two directions. By controlling the direction of current flow through the motor, the actuator can be retracted or extended. The actuator is operated from a switch on the instrument panel that is labeled ENGAGE, HOLD, and RELEASE. When the actuator is operated towards the engage or release direction, the shaft will either retract or extend (respectively) until it makes contact wilh a limit switch that breaks the circuit and stops the motor. Figure shows the electrical control circuit for the linear actuator. Revised: 1 April

7 Sedtion 2 Models 269A, M-55Al A-1 B & C - Appx B Table B-2. PERODC NSPECTONS What to nspect Hour nspection Perform a complete Daily nspection, 25, 50- and 100-Hour nspection and any required special inspections as a part of the 200-Hour nspection listed below. NTALS 1. Visually inspect steel linear actuator attachment mating frame fitting strap for bending, cracks or other physical defects. 2. Dye penetrant inspect cluster fitting attachment lugs for tailboom support strut on basic aft cluster fittings (fittings with thin lug to inch) for cracks in accordance with the dye penetrant inspection instructions listed in Basic HM, Section 2. mmediately retire from service and tag as unserviceable any center frame aft cluster fitting found to have unrepairable cracks. (Refer to Basic 3341, Section 13 for repair criteria and procedure.) A -3 (thick lug to inch) cluster fitting must be used for replacement (Basic HM, Section 13). 3. Check attachment nuts at tail boom support strut stainless steel end fittings 269A and -5 for proper torque ( in.-lbs.). 4. On helicopters which incorporate 269A or -3 belt drive clutch control assemblies which have not been modified in accordance with Service Notice N-226, disassemble belt drive clutch spring assembly and inspect entire length of cable for wear or damage (Basic HM, Section 10). 5. Visually inspect induction air filter in accordance Basic HM, Section 2. (No cleaning allowed on foam filter; change every 200 hours (maximum life) or when dirty.) Reissued: 20 May 1993 Revised: 07 Nov 1995

8 Ssction 2 Models 269A, TH-55A, A-, B & C - Appx B Table B-2. PERODC NSPECTONS What to nspect Hour nspection NOTE 1 NTALS Perform a complete Daily nspection, 25, 50-, loo-, and 200-Hour nspection and any required special inspections as a part of the 400-Hour nspection listed below. The 300-Hour nspection is not required as part of the 400-Hour nspection unless specified otherwise Remove main rotor blades; clean blades thoroughly; inspect tip for security; trailing edge bonding and rivets for security; bond between skin and spar for voids. Perform a 1OX visual inspection of the main rotor blade root fitting installation for paint or sealant cracking or blistering and for bond separation at the interface of blade skin doubler and upper and lower root fittings. (269A/TH-55A, A-1 and 269B only. nspection not required for 269A main rotor blades.) After first 500 hours service: Without disassembly, check torque of five outboard main rotor blade root fitting attach bolts in correct sequence to assure that a minimum of 50 to 60 in.-lbs. is maintained (Refer to Basic HM, Section 8 for torque check procedure). Do not loosen and retorque bolts. f any washer is loose under head of two outboard bolts, remove blade and perforrr special criteria inspection of blade (Basic HM, Section 8). (Refer to 100-Hour nspection for firs 400 hours service.) Remove main rotor pitch bearing assemblies (DO NOT DSASSEMBLE FOR NSPECTON); inspect case for cleanliness, cracks, wear and damage; inspect bearing operation (Basic HM, Section 8). nspect lead-lag bearing sleeves for cracks, wear and other damage. Main rotor flapping hinge bolts for damage; inspect bearings and sleeves in main rotor head for damage (Basic HM, Section 8). Droop stop retainer ring for cracks, deformation, excessive wear and pounding by droop stop lug. nspect lug. Main rotor swashplate, swashplate scissors, swashplate gimbal sleeve and bushings for wear and damage. (All 269 Series helicopters with stainless steel spring retainer in clutch control spring assembly) Clutch disengaged, without disassembly, visually inspect entire clutch control spring assembly for wear and defects. Clutch engaged, inspect for wear on exposed area of stainless steel spring retainer. (Check for wear on spring retainer plastic sleeve, if installed) Disassemble belt drive clutch spring assembly and inspect entire length of cable for wear or damage (Basic HM, Section 10). nspect clutch cable terminal end for bending (Basic HM, Section 10) Perform 400 hour engine inspection in accordance with manufactures publications Reissued: 20 May 1993 Revised: 12 Feb 1997