SD3-60 AIRCRAFT MAINTENANCE MANUAL ASSEMBLY - MAINTENANCE PRACTICES (SIX-BLADED PROPELLERS, MODEL HC-A6A-3A, POST HARTZELL SERV. BULL.

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1 SD3-60 AIRCRAFT MAINTENANCE MANUAL z AMM PROPELLER ASSEMBLY - MAINTENANCE PRACTICES (SIX-BLADED PROPELLERS, MODEL HC-A6A-3A, POST HARTZELL SERV. BULL. 168) NOTE: Five-bladed propeller assemblies (aircraft equipped with PT6A-65R or -65AR engines). Refer to , pb Servicing A. Lubricate blade bearings Refer to , pb Removal/Installation Special Tools & Equipment:- Table, Propeller Setting: Protractor, Blade Setting: Puller, Beta Ring: Sling, Propeller: Dial Indicator gauge, (Run-out checks): Rig, Unfeathering: T A T T T Operators Supply Operators Supply A. Remove a Propeller Assembly (1) Remove the spinner dome and its six filler plates at the blade positions; retain attachment screws and washers. (2) Remove cowl 430AT and hinge down the intake cowl 420BB - (Refer to , pb1.). (3) Refer to Figure 201. Remove propeller reversing lever to disengage associated slipper block from the propeller low stop collar (beta ring) as follows:- (a) Disconnect lever (2) from clevis (3) at front end of push-pull control terminal (4) by removing split pin, castellated nut and bolt (5). (b) Disconnect lever from Beta valve plunger (6) on propeller governor (7) by removing split pin, washer and pin (8). Remove lever and remove spacer (9) and bushing (10) to prevent loss of these parts. NOTE: Do not remove carbon slipper block (11) from lever. Page 201

2 z SD3-60 AIRCRAFT MAINTENANCE MANUAL Reversing Lever - Removal/Installation Figure 201 Page 202

3 SD3-60 AIRCRAFT MAINTENANCE MANUAL z (4) Remove the two nuts and washers which secure the support bracket shared by (a) the fine pitch back-up and reverse pitch indication mechanism and (b) the propellers right hand de-icing brush block assembly to: the right lower side of the thrust bearing cover on the reduction gearbox. Extricate the slipper block from the low stop coller on the propeller and temporarily stow the complete assembly clear of the propeller spinner bulkhead. (5) Fit beta ring puller to the low stop rods support ring around propeller piston and wind the ring forward such that the low stop collar is positioned to provide optimum access to propeller mounting bolts. (6) Sling the propeller. (7) Break the lockwire and remove the 12 attachment bolts and washers which secure the propeller assembly to the engine's propeller shaft. Pull the propeller forward to disengage from the dowel pins on the propeller shaft flange and lower unit clear. (8) Remove the O-ring from the propeller shaft. B. Install a Propeller Assembly (1) If propeller assembly to be installed is in 'shipped' condition, carry out preparation procedure detailed in para C. (2) Clean the respective mounting faces of the propeller assembly and the engine's propeller shaft. Remove any sharp edges which might prevent mating. (3) Ensure that the two dowel pins are fitted to the mounting flange on the engines propeller drive shaft. (4) Fit O-ring, Pt. No. PRP to drive shaft. NOTE: Use PRP Compound 1487 or 8307 to fit O-ring. (5) Fit beta ring puller to the low stop rods support ring around propeller piston and wind the ring forward such that the low stop collar is positioned to provide optimum access to the propellers mounting flange for installation. (6) Sling the propeller and raise to installation position. (7) Attach propeller to drive shaft on engine, engaging dowel pins. Ensure that complete and true surface contact is established and fit attachments as follows:- (a) Apply MIL-T-5544 Petrolated Graphite to threads and shanks of the 12 bolts, Pt. No. B-3347 (colour-coded black) and to the bolt-to-washer interface of the 12 washers, Pt. No. A (b) Fit the bolts and washers, torque to 40 ft lb and then to 80 ft lb following torque sequence 'A'. Page 203

4 z SD3-60 AIRCRAFT MAINTENANCE MANUAL Torquing Sequences - Propeller Attachment Bolts Figure 202 Page 204

5 SD3-60 AIRCRAFT MAINTENANCE MANUAL z Final torque all bolts using sequence 'B' to ft lb. (d) Wirelock bolts together in pairs. (8) Remove sling. (9) Remove beta ring puller. (10) Rotate propeller until the synchrophasing target plate on the rear of the spinner bulkhead covers the magnetic pick-up on the left hand de-icing brush block assembly. Check that the gap between pick-up and target is in. Adjust pick-up position, if necessary, tighten locknuts and wirelock. (11) As a shared assembly, re-attach (a) the fine pitch back-up and reverse pitch indicating mechanism and (b) the propellers right hand de-icing brush block to: the right lower side of the thrust bearing cover on the reduction gearbox. Ensure pitch mechanism slipper block is inserted in the low stop collar on the propeller. Torque tighten the support brackets two attachment nuts to lb in. (12) Refer to Figure 201. Refit the propeller reversing lever as follows:- (a) Press bushing (10) into centre hole of lever (2). (b) Position slipper block (11) in propeller low stop collar. Insert centre boss of lever (2) into clevis on Beta valve plunger (6) of propeller governor (7). Secure lever in clevis with pin (8), washer and split pin. Press spacer (9) into upper hole in propeller reversing lever (2). Secure lever in clevis (3) with bolt (5) and castellated nut. Torque nut to between 24 and 36 lb in. and install split pin. (13) Rotate propeller and check that the side clearance of both slipper blocks in the low stop collar is to in. NOTE: Discard any block with clearance in excess of that quoted and appropriately lap evenly the sides of any tight block to come within tolerance. (14) Check alignment of both propeller de-icing brush blocks. Refer to , pb201. (15) Operationally check propeller heating for one 'stepped' cycle only. Refer to , pb201. (16) Refit spinner and cowlings. (17) Rotate propeller and check that clearance exists between the spinner and engine cowlings. (18) Remove the POWER, FUEL and PROP lever cover assembly from the top of the centre console in the flight compartment. Page 205

6 z SD3-60 AIRCRAFT MAINTENANCE MANUAL (19) Refer to , pb1. Start and run engine and perform the following checks:- (a) Set reverse maximum power. NOTE: This will set the operational max. reverse blade angle (the angle set during propeller assembly merely provides overtravel). (20) Start opposite engine and function check the propeller synchrophasing system. Refer to , pb201. (21) Shutdown engines and refit console cover after any required adjustment to the reverse stop associated with the newly installed propeller. C. Prepare Propeller for Installation General Information This procedure relates to the preparation of a propeller assembly from a received (shipped) condition. The propeller has been assembled and balanced by the manufacturer/overhaul agency, then dismantled for convenience of shipping. The shipping condition is:- ITEM QTY REMARKS Blades (6) Packaged with root ends wrapped and bagged to maintain bearing assemblies, preserve the grease and keep out foreign matter. Hub (1) Assembled without sealant in joint, but equipped with balance weights where necessary and crayon/pencil idented for (a) matching blade positions and (b) subsequent axial orientation of the propeller cylinder. Low Stop Collar (Beta ring) (1) ) ) ) Low Stop Rods support ring (1) ) Packaged together and crayon/pencil idented to ensure re-establishment of previously installed alignment with associated low stop rods. Low Stop (Beta) rods (3) Packaged together, each (a) complete with spring cans and adjustment nuts and (b) tape idented for associated installation position on hub, cylinder and piston. Page 206

7 SD3-60 AIRCRAFT MAINTENANCE MANUAL z ITEM QTY REMARKS Pitch change rod,cylinder/ reverse pitch stop and feathering springs assembly Procedure Refer to Figure 203. (1) Separate engine and piston halves of hub as follows:- (1) Fork, pitch change (1) ) Piston (1) ) ) Nut, piston retaining (1) ) ) ) ) ) Packaged together. Cylinder and piston are crayon/pencil idented to ensure previously installed orientation on propeller hub can be re-established. De-icer wiring harness (6) Supplied in a single bag, including clips and tie straps. Spinner dome, bulkhead and filler (blade closing)plates assembly (1) Supplied assembled to provide spinner dome rigidity. (a) Where fitted, mark location of any balance weights attached across the hub joint. Remove weights and retain for subsequent re-installation. (b) From the periphery of the assembled hub, remove the nuts and washers from the 12 short and 6 long bolts. Remove the bolts. CAUTION: DO NOT USE SCREWDRIVERS OR SIMILAR SHARP TOOLS IN AN ATTEMPT TO PRY THE HUB HALVES APART. Use plastic/wood wedges to gently separate the hub halves. (d) Check that the two jointing guide bushes have remained with the engine half hub. (2) Remove spinner dome and filler (blade closing) plates from the spinner bulkhead. (3) Install engine half hub on propeller setting table spindle as follows:- (a) Set low stop collar (beta ring) over spindle with its three rod attachment holes uppermost. Page 207

8 z SD3-60 AIRCRAFT MAINTENANCE MANUAL Propeller Assembly Figure 203 Page 208

9 SD3-60 AIRCRAFT MAINTENANCE MANUAL z (b) Place spinner bulkhead (sliprings downwards) over spindle. Fit O-ring, Pt. No. PRP to spindle boss. (d) Mount engine half hub on spindle, engaging dowels. (e) Fit the 12 propeller mounting bolts and washers. In staggered sequence, torque to installation value ie., 100 to 105 ft lb. (4) Select blade idented No. 1 and install in correspondingly idented socket in the engine half hub as follows:- (a) Remove wrapping from blade shank, taking care not to disturb grease and bearing assemblies. CAUTION: TO PREVENT DAMAGE TO THE BLADE DE-ICER LEADS DURING SUBSEQUENT BLADE ANGLE CHECKS, TEMPORARILY TAPE THE WIRING TO MAINTAIN IT WITHIN THE RECESS IN THE BLADE COUNTERWEIGHT ARM BEFORE CONTINUING. (b) Introduce blade shank assembly to socket and carefully tap in with a soft hammer, ensuring:- 1 Quad seal engages in outer recess of socket. 2 Blade counterweight arm lies clockwise (viewed from above). 3 The split in the outer race of the blade retention bearing is at 90 to the hub parting surface. CAUTION: SUITABLY SUPPORT BLADE TO PREVENT IT FROM FALLING OUT OF SOCKET. (5) Repeat (4) for blade Nos 2 thru 6. (6) Rotate pitch change blocks on each blade drive arm such that the side idented at both ends with the symbol 'O' faces upwards from setting table. (7) Place the 'star-shaped' drive fork on top of the pitch change blocks with the thick wall of its six fork projections facing downwards. NOTE: Do not attempt to engage fork with blocks at this stage. (8) Install piston half hub to engine half hub as follows:- (a) Apply a thin coating of General Electric RTV Sealant to the full mating surface of the engine half hub. Page 209

10 z SD3-60 AIRCRAFT MAINTENANCE MANUAL (b) Axially orientate piston half hub such that its crayon/pencil idented sockets align with the correspondingly idented sockets in the engine half hub. Lower to engage the two guide bushes in the engine half hub. Use a soft hammer to fully mate the two hub halves. Check that some of the sealant has squeezed out from between the halves all around the mating surfaces. (d) Insert the 6 long and 12 short hub clamping bolts from the piston half hub side and install the attachment washers and self-locking nuts. (e) Nominate the longer bolts as numbers 1 thru 6 in rotation and to ensure uniform pulldown between the hub halves, stagger the sequence of torquing as follows:- 1 Torque nuts 1, 3 and 5 to 22 lb ft (30 Nm). 2 Torque nuts 2, 4 and 6 to 22 lb ft (30 Nm). (f) Provide optimum access and torque the short bolts as follows:- 1 Without dislodging the drive fork which rests loosely on the blade pitch change blocks within the hub, manually move each blade incrementally in turn (or simultaneously if assistance is available) clockwise towards fine pitch until the counterweight arms have cleared the nuts on the short bolts. 2 Torque all 12 nuts to 22 lb ft (30 Nm). 3 Manually return blades to the feather position (counterweight arms level). (9) At each blade in turn:- (a) Pull blade upwards (away from setting table) then push downwards and check that no fore and aft movement of the blade shank in the hub socket is evident ie., manufacturer/overhaul agency setting of the shank assembly pre-load is adequate. NOTE: Where play is evident, gain access to the shanks pre-load plate set screw through the front of the piston hub half. The set screw is located centrally in the associated blade shank. Slacken jam nut on the screw and torque the screw to 12 lb ft (16 Nm). Apply adhesive (General Electric GE RTV 102) to exposed threads of set screw and tighten the jam nut. (10) Attach spinner bulkhead to engine half hub as follows:- (a) Raise bulkhead to contact the half hub and axially orientate until the three cut-outs in its inner periphery expose the low stop rod holes in the hub. (b) Fit the six bolts and washers which secure the bulkhead to the hub and torque to lb in. (5-7 Nm). NOTE: Do not wirelock bolts until after subsequent check of slipring run-out. Page 210

11 SD3-60 AIRCRAFT MAINTENANCE MANUAL z (11) Check slipring run-out:- (a) Suitably secure a dial indicator gauge to the setting table; bring pointer into contact with a slipring and adjust dial to zero. (b) Rotate propeller slowly and note the deviation from a true plane as indicated by the gauge. NOTE: The run-out should not exceed in. in total and/or in. within any four inches of slipring travel. If tolerances quoted in preceding note are not met, then: excess run-out may be corrected by circumferentially varying the torque of the spinner bulkhead attachment bolts within their specified limits of lb in. (5-7 Nm). (d) Wirelock bulkhead attachment bolts in pairs. (12) Install each of the three low stop rod assemblies as follows:- (a) Choose an assembled rod and check for its required crayon/pencil idented position in the hub. (b) Except for the spring can self locking adjustment nut, remove the following nuts from the assembly. 1 The two fine pitch adjustment nuts (remove from low stop rod). 2 The two feather stop adjustment nuts (remove from spring can body). Check that the spring retainer at the engine end of the spring can is flush with the can end; if not, set spring can adjustment nut to comply. (d) Lubricate the engine end of the low stop rod with a film of approved grease. (e) Fully insert rod through designated holes in the hub assembly. (13) Engage the six pitch change blocks in the drive fork as follows:- (a) Manually place the blades into an equal reverse position for better accessibility when engaging fork. (b) Axially manoeuvre fork to permit engagement with pitch change blocks. NOTE: Leave blades at reverse pitch to facilitate subsequent step (14). (14) Install the pitch change rod, cylinder/reverse pitch stop assembly and feathering springs assembly as follows:- Page 211

12 z SD3-60 AIRCRAFT MAINTENANCE MANUAL (a) Insert O-ring, Pt. No. B-1070 in face of piston half hub. (b) Apply Aeroshell Compound 08 (MIL-T-5544) to the fork engagement threads at engine end of pitch change rod. Lower assembly into the hub, passing the low stop rod spring cans through the cylinder flange. (d) Rotate the pitch change rod to fully thread engage with the blade drive fork. (e) Manually move the blades to feather to seat all parts. (f) Install the nine attachment bolts in the cylinder flange. Torque to 16 lb ft (22 Nm) and wirelock. (15) Install the low stop collar (beta ring) and check/set to its datum position as follows:- (a) Slacken the three set screws on the periphery of the collar. (b) Raise the low stop collar and axially orientate to receive the three low stop rods at the correspondingly identified positions on the collar. Progressively rotate low stop rods into collar (one or two turns at a time) until they 'bottom', then back off until the flat on each rod lines up with the associated set screw. Tighten the set screws. (d) Check/establish the datum position of the low stop collar as follows:- NOTE: The low stop collar is in its datum position when its rear surface is in. aft of the engine side half hub rearmost surface (the jointing face of the propeller flange). The check should be made close to each of the low stop rods in turn. If necessary, adjust the self locking nut at the front of each low stop rod spring can to establish the datum. (16) Check the low stop collar run-out as follows:- (a) Suitably secure a dial indicator gauge to the setting table; bring pointer into contact with the rear face of the collar and adjust dial to zero. (b) Slowly rotate the propeller and note the deviation from a true plane as indicated by the gauge. The total run-out must not exceed in. NOTE: If run-out exceeds in. it is best absorbed towards the cylinder end of the hub by minimally advancing towards the setting table, the spring can adjustment nut on that or those low stop rod/s which are closest to the collar low point until run-out is within tolerance. This usefully employs the minus in. tolerance applied to the low stop collars datum position, thus maintaining the datum position acceptable. Page 212

13 SD3-60 AIRCRAFT MAINTENANCE MANUAL z (17) Install the piston as follows:- (a) Thread the two feathering pitch adjustment nuts onto each low stop rod spring can and run the nuts to the engine-side ends of the cans. (b) Lubricate with engine oil and install the following seals in the piston. 1 Pitch change rod O-ring, Pt. No. A Piston O-ring, Pt. No. PRP Felt seal, Pt. No. B Place piston over the cylinder and press down until it seats beyond the threaded section of the pitch change rod. (d) Thread the self-locking pitch change rod nut onto the end of the pitch change rod; torque nut to 40 lb ft (54 Nm). (18) Check blade track as follows:- (a) Operate setting table pressure rig to position blade tips at flat pitch with respect to hub axis. (b) Using a suitable reference, eg., measuring stick, rotate propeller and check that the total variation of blade track at tips for all blades does not exceed 0.12 in. (19) Check floating pitch angle of blades. (a) Adjust rig pressure to place the No. 1 blade at a pitch angle within the range 7.5 to 17.5 deg. NOTE: Measure angle at the 42 in. radius checking station on the blade whilst torquing the blade by hand towards feather (to ensure associated pitch change block is properly seated against the fork). Record angle achieved. (b) Record the angle for blade Nos 2 thru 6 in turn, again observing NOTE at (a). Check that the total variation in the range of angles achieved does not exceed 0.2 deg. (20) Set/check blade angles for full reverse, feather and fine pitch pick-up as follows:- (a) To check/set full reverse pitch: 1 Raise rig pressure slowly to a maximum of 135 psi to move drive fork into contact with the internal reverse stop (fitted to engine side of cylinder). Page 213

14 z SD3-60 AIRCRAFT MAINTENANCE MANUAL Low Stop Collar Datum Setting and Runout Check Figure 204 Page 214

15 SD3-60 AIRCRAFT MAINTENANCE MANUAL z 2 Maintain pressure and check angle of blade No. 1 at the 42 in. radius checking station. NOTE: Required reverse blade angle is -16 ± 0.5 deg. 3 If reverse blade angle is incorrect, establish amount of overshoot/undershoot and:- a b c d Relieve pressure. Remove piston. Remove cylinder assembly. Detach reverse stop ring from cylinder and refit after appropriately adjusting the jointing shim thickness. NOTE: - One shim (Pt. No. C-4902) will affect reverse blade angle by approximately 0.7 to 0.8 deg. - If over six shims are required, make a visual check that attachment screws will have a minimum engagement of five threads. e Torque tighten reverse stop attachment screws to 40 in. lbs. 4 4 Repeat steps 1 and 2 and if reverse blade angle is correct, repeat for blade Nos. 2 thru 6. (b) To set feathering angle: 1 Check that all three feather stop adjustment nuts are contacting the engine-side face of the piston flange (all pressure released from piston); if necessary, adjust stop nuts to comply. 2 Check angle of blade No. 1 at the 42 in. radius checking station. NOTE: Required blade feathering angle is 75.5 ± 0.5 deg. 3 If feathering angle is incorrect, apply sufficient rig pressure to drive piston off the stop nuts and equally turn the nuts in the required direction. NOTE: Turn nuts clockwise to increase feathering angle or counterclock-wise to decrease feathering angle. One full turn of the nuts equals approximately 1.5 deg. 4 After each correction attempt, depressurize the piston and re-check feathering angle at blade No. 1. NOTE: When satisfactory angle is achieved, check that feathering angles on blade Nos 2 thru 6 are within tolerance. Page 215

16 z SD3-60 AIRCRAFT MAINTENANCE MANUAL 5 Tighten the associated locknut against each feathering stop nut to a torque of 16 lb ft (224 Nm). Wirelock each stop nut to its locknut. To set flight fine pitch pick-up blade angle: 1 Install the rod end ring on the forward ends of the low stop rods as follows:- a b c Thread a locknut onto each rod end. Place ring over the three rods. Thread a self-locking nut onto each rod. NOTE: The ring should be left unclamped at this stage ie., locknuts slackened and threaded close to the spring cans. 2 Set protractor to the required flight fine pitch pick-up blade angle; this is 12.5 ± 0.2 deg. 3 Place protractor on the 42 in. radius checking station of blade No. 1 and slowly raise rig pressure in stages until the protractor bubble centres. Lock in pressure to maintain the blade angle. 4 Run the three self-locking nuts down until the rod end ring just contacts the pistons integral fine pitch pick-up boss (ie., impose no load on the low stop rods). 5 Check flight fine pitch pick-up angles on blade Nos 2 thru 6 are within tolerance. NOTE: a If one or more blades are outside of tolerance, release rig pressure and equally turn the three adjustment nuts (clockwise to increase the angle or counterclockwise to decrease the angle) by required amount. b One full turn of the nuts equals approximately 0.5 deg. of pitch. 6 After each correction attempt, slowly raise rig pressure and arrest immediately the pistons fine pitch pick-up boss contacts the rod end ring. Check all six blade angles. NOTE: When satisfactory blade fine pitch pick-up blade angles are achieved, release piston pressure and run the three locknuts out and tighten against the engine-side face of the rod end ring. 7 Slowly raise rig pressure to a maximum of 135 psi and drive the blades to full reverse pitch. Maintain reverse pitch and recheck low stop collar run-out as detailed in step (16). NOTE: In the event that referred adjustment to correct out-of-tolerance run-out is needed, the flight fine pick-up blade angle settings must be rechecked. Page 216

17 SD3-60 AIRCRAFT MAINTENANCE MANUAL z (21) Refer to Figure 205. Install each of the blade wiring harnesses as follows:- (a) Connect the two wires on the spinner bulkhead end of the harness to the two terminals on the bulkhead; secure each with a washer, lock washer and nut as shown. (b) Remove any temporary tape restraining blade heater socket and wiring in the counterweight arm cavity. Gently pull out socket and leads. Pot the area of the cavity shown shaded with GE RTV 102 (General Electric) adhesive. (d) Connect harness plug to blade heater socket and secure with a tie strap positioned between the lead wires as shown. (e) Loop the heater leads and press into the counterweight cavity, together with connector. Smooth out potted area. (f) Assemble the two cable clamps (P-clips) to the harness; attach one to the blade counterweight arm and the other to the spinner bulkhead as shown. Secure each with a screw and washer. (22) Remove propeller from setting table. 3. Dynamic balancing A. Equipment required Part No. Qty. (1) Balancer/Phazor unit 177M-6A 1 (2) Magnetic pick-ups (3) Magnetic pick-up cable (4) Magnetic pick-up brackets (5) Accelerometers 4177B 2 (6) Accelerometer cable (7) Accelerometer bracket (8) Interrupter (9) Balance chart - 1 B. Test equipment installation Refer to Figure 206. Install equipment on each engine as follows:- (1) Remove access panel No.430AT and 420AB Page 217

18 z SD3-60 AIRCRAFT MAINTENANCE MANUAL De-icing Harness Installation Figure 205 Page 218

19 SD3-60 AIRCRAFT MAINTENANCE MANUAL z (2) Install accelerometer (3) Install magnetic pick-up and interrupter plate. Set the magnetic pick-up to achieve a clearance of (3.17 mm) to the interrupter plate. (4) Install counterbalance washers at the screw position diametrically opposed to the interrupter plate. (5) Connect accelerometer cables to the accelerometers on each engine. (6) Connect magnetic pick-up cables to the magnetic pick-ups on each engine. (7) Route cables along the engine cowl, wing leading edge and through the forward emergency exit doors. NOTE: (a) Care should be taken to ensure that cables are routed away from the engine exhausts and are firmly secured to the aircraft structure with adhesive tape. (b) Ensure that the cables are not nipped excessively when the emergency exit doors are closed. (8) Refit access panel 430AT. (9) Connect DC power to the Balance Unit. NOTE: (a) The unit will operate satisfactorily from an external supply provided that the voltage is between 12 and 28 volts. (b) A convenient internal supply can be taken from distribution panel 2D using the redundant FERRY FUEL circuit breaker No.222. (10) Connect accelerometer and magnetic pick-up cables to the balance unit. (a) Connect the left and right engine accelerometer cables (three pin) to channels A and B respectively. (b) Connect the left and right engine magnetic pick-up cables (two pin) to channels A and B respectively. C. Pre-test notes (1) The propellers must be balanced to within.2 IPS at 1500 PRPM and 2000 lb.ft torque. (2) Observe starter limitations between tests. (3) The optimum test results are realised when the PHAZOR light flashes constantly around the face of the clock with the IPS indicator at less than.2. Page 219

20 z SD3-60 AIRCRAFT MAINTENANCE MANUAL Test equipment installation Figure 206 Page 220

21 SD3-60 AIRCRAFT MAINTENANCE MANUAL z D. Balancer unit controls Refer to Figure 207. (1) Set the controls as follows:- (a) FUNCTION switch - set to 'A' for left propeller or 'B' for right propeller. (b) INTERRUPTER LOGIC - set to SINGLE. MAGNETIC PICK-UP switch - set to INDEPENDENT. (d) R.P.M. RANGE - set to X10. (e) R.P.M. TUNE dial - set to 150. E. Balance a propeller (1) Start the engine. Refer to , pb1. (2) Set P.R.P.M. to 1500 and torque to 2000 lbs.ft. (3) Close circuit breaker (No.222 for FERRY FUEL on distribution panel 2D if recommended supply is used). (4) Press TEST button to synchronize the o'clock position light in the PHAZOR with the accelerometer position. Release test button. NOTE: If the propeller is out of balance, one light will flash constantly. (5) Observe which light(s) in the phazor is (are) flashing and tune the balancer unit as follows:- (a) Press the VERIFY TUNE button and check if the position of the light(s) change. (b) If the flashing light(s) in the phazor changes, adjust the R.P.M. TUNE (with the VERIFY TUNE button pressed) until flashing light(s) return(s) to the original position(s) as in (5) Release the VERIFY TUNE button and check that the light position is unchanged. (d) Repeat (b) until the conditions detailed in are met. (6) Record the 'out of balance' clock position and the amount of imbalance from the IPS scale on the balance chart. Refer to Figure 208. NOTE: If the IPS reading is off scale, press PUSH FOR SCALE 2 button. The graduations will then read 0 to 10 instead of 0 to 1.0. (7) Stop engine. Refer to , pb1. Page 221

22 z SD3-60 AIRCRAFT MAINTENANCE MANUAL Balancer unit controls - Model 177M-6B Figure 207 Page 222

23 SD3-60 AIRCRAFT MAINTENANCE MANUAL z (8) Add weights as appropriate to correct the imbalance. Refer to Figure 208. (9) Retest as detailed in E(1) thru (8) until propeller balance is within.2 IPS. (10) Set the function switch to B and balance the propeller of the right engine as detailed in E(1) thru (9). F. Restore the aircraft (1) Open circuit breaker No.222 (2) Remove access panel 430AT (3) Disconnect cables and remove accelerometer, magnetic pick up and interrupter (4) Refit access panels. Page 223

24 z SD3-60 AIRCRAFT MAINTENANCE MANUAL Balance chart (6 bladed propeller) Figure 208 Page 224