SD3-60 AIRCRAFT MAINTENANCE MANUAL

Transcription

1 AMM HYDRAULIC POWER - GENERAL 1. General This chapter is concerned solely with that portion of the total hydraulic system which provides power (main and emergency) for the use of the service systems. The main system power supply provides for the operation of the following services, each of which is dealt with in the referenced chapter within this manual:- Wing flaps : Landing gear : Wheel brakes : Nosewheel steering : Refer to , pb1. Refer to , pb1. Refer to , pb1. Refer to , pb1. 2. Pipelines and couplings With the exception of flexible pipes at the engine-driven pumps and the services actuator units, system components are connected by rigid pipelines. The rigid pressure pipes are manufactured from stainless steel tubing; return and pump inlet piping are of light alloy. The pipe ends are flared and connections made with standard American AN/MS cone end couplings and nuts Page 1

2 AMM PIPE CONNECTIONS (STAINLESS STEEL) - MAINTENANCE PRACTICES 1. Servicing VOI-SHAN metallic seals are employed at each pipe joint in the nitrogen lines and may also be used on stainless steel hydraulic pipes to cure leaks or when replacing pipes. Pipe Dia. Part No. Torque Value 3/16 VSF1015N3B in.lbs. 1/4 VSF1015N4B in.lbs Page 201

3 AMM TEMPORARY REPLACEMENT OF DAMAGED RIGID PIPES BY FLEXIBLE PIPES - MAINTENANCE PRACTICES 1. Servicing Refer to , pb Page 201

4 AMM HYDRAULIC POWER, MAIN SYSTEM - DESCRIPTION/OPERATION 1. Description A. General The components incorporated in the main system are: - diagrammatically located. Refer to Figure 1. - geographically located. Refer to Figure 2. Data relating to the system is given in para 2. B. Power generation With the pump inlet shut-off valves open and engines running - fluid is fed from the pressurised reservoir to the left and right engine-driven pumps. With no service operating, the variable displacement, pressure compensated pumps deliver fluid under a continuously monitored pressure of p.s.i. (normal leakage through the pump valves is directed into the pump case drain lines and routed through non-return valves back to the reservoir). NOTE: fluid entering the reservoir, with the exception of that from landing gear up lines (when emergency down is selected) passes through a 3 micron filter. The filter unit incorporates a bypass valve. Delivery fluid from each pump passes through opposed non-return valves into a common pressure line which also incorporates a 15 micron filter. A pressure switch and a high pressure relief valve are incorporated upstream of the nonreturn valve in each pump delivery line. The pressure switch will illuminate a warning light on the flight deck panel 1P in the event of pump or engine failure. NOTE: In either contingency the remaining pump is capable of meeting the maximum demands upon the system. The high pressure relief valve is embodied to prevent excessive heat generation should the related pumps internal compensating valve fail when on maximum flow. NOTE: When operated, the relief valve will drop the pressure in the associated line to 450 p.s.i. approximately. Downstream of the filter in the common pressure line, fluid under pressure is directed to four accumulators; these are:- (1) The main system accumulator (which acts as a smoothing device for the pumps and allows for sudden changes in flow demands) Page 1

5 SD3-60 AIRCRAFT MAINTENANCE MANUAL (2) The landing gear emergency accumulator. (3) The emergency brake accumulator. (4) The flap system accumulator. NOTE: except the main system accumulator are pressurised through integral non-return valves. To prevent over-pressurisation of the reservoir by thermal expansion or when filling or inflating - relief valves are incorporated in the reservoir inflation and fluid return lines. C. Ground connectors 2. Data The system can be maintained 'on load' for ground testing of the service systems by connection of a hydraulic ground servicing rig. The rig connects to self-sealing PRESSURE and RETURN connectors on the hydraulic servicing panel in the left main landing gear fairing. Reservoir replenishment is via a FILL coupling on the servicing panel, the system charge line of which incorporates a 15 micron filter. Fluid: DTD 585B (OM 15) Reservoir capacity: 1.1 lmp. Gal (1.32 U.S. gal; 5 litres) System operating pressure (no flow) psi. Inflation pressures:- Accumulators: 1350 psi. at 20 C Reservoir: 25.0 psi. at 20 C Component pressure settings:- High pressure relief valves: psi. Thermal relief valves (fluid return lines and reservoir inflation line):- Relief pressure: Re-seat pressure: psi. 120 psi Page 2

6 Hydraulic Power - Schematic Figure Page 3

7 SD3-60 AIRCRAFT MAINTENANCE MANUAL Location of Components Figure Page 4

8 AMM HYDRAULIC POWER, MAIN SYSTEM - SERVICING 1. Release hydraulic pressure Hydraulic pressure may be off-loaded from the main system, the landing gear and wheelbrakes emergency lines and the accumulator augmented flap lines are respectively detailed in para A to D inclusive. WARNING: WHERE SUBSEQUENT OPERATIONS REQUIRE DISCONNECTION OF RETURN LINES OR LINES WHICH OPERATIONALLY ALTERNATE AS PRESSURE RETURN LINES - THEN IT WILL ALSO BE NECESSARY TO DEFLATE THE PRESSURIZED RESERVOIR. A. Release main system pressure. (1) Check reading on MAIN SYSTEM gauge on flight compartment panel 7P; if not indicating ero, operate toe brakes repeatedly until ero pressure is displayed. B. Release emergency brake pressure. (1) Release main system pressure (para A). (2) Select brake EMERGENCY HYD. control handle on left side of flight compartment centre console to EMERGENCY. (3) Refer to , pb301. Provide electrical power and check that appropriate indication C/B on distribution panel 1D is closed; depending on aircraft effectivity, this may be C/B 54 or 101. (4) Operate toe brakes until pressure shown on EMERGENCY WHEELBRAKES gauge (panel 7P) falls to and stabilies at accumulator inflation pressure relative to ambient temperature. Refer to Table 301. TEMP INFLATION PRESSURE (psig) C F (psig) ± ± ± ± ± ± 55 Table 301- Accumulator Inflation Pressure Page 301

9 SD3-60 AIRCRAFT MAINTENANCE MANUAL C. Release emergency landing gear pressure. With the landing gear down and locked, carry out the following:- (1) Release main system pressure (para A). (2) Pull L/GEAR DOWN - EMERGENCY control lever (flight compartment roof console) to down position. (3) Refer to , pb301. Provide electrical power and close C/B No. 204 on distribution panel 2D. (4) Check that pressure shown on EMERGENCY LANDING GEAR pressure gauge on Panel 7P falls to and stabilies at accumulator inflation pressure relative to ambient temperature (Refer to Table 301). NOTE: After operations for which release of pressure was necessary have been carried out, the restoration drill must be effected. Refer to , pb201. D. Release pressure from the flap accumulator. (1) Release main system pressure (para. A). (2) Refer to , pb301. Provide electrical power. (3) Ensure C/B No. 185 on panel 2D is closed. (4) With reference to the hydraulic service panel:- (a) Open FLAP accumulator valve. (b) Operate flaps up and down between 5 and 30 positions until pressure shown on inflation check gauge drops to and stabilies at accumulator inflation pressure relative to ambient temperature. Refer to Table 301. (c) Close accumulator valve and evacuate charging connection. 2. Inflate/Check Accumulator and/or Reservoir Inflation CAUTION: USE OF SPANNERS TO INCREASE LEVERAGE ON THE VALVE KEY WHEN CLOSING AN INFLATION VALVE AFTER SERVICING IS PROHIBITED. SUCH ACTION CAN CAUSE VALVE DAMAGE AND CONSEQUENTLY GAS LEAKAGE. THE VALVES SHOULD BE FIRMLY CLOSED BY HAND TIGHTENING MEANS ONLY. NOTE: 1. When inflating or checking a units inflation, system fluid should be at ambient temperature. 2. The inflation valves should be checked for leaks by the application of a bubble solution after closing Page 302

10 A. Inflate an accumulator (1) Connect a supply of nitrogen to the accumulator INFLATION VALVE on the hydraulic servicing panel (dry air may be used only in an emergency situation, and the accumulator should be re-charged with nitrogen at the earliest opportunity). (2) Open appropriate accumulator valve (SYSTEM, FLAP, L/G EMERGENCY or BRAKE). (3) Charge unit until ACCUMULATOR pressure gauge reads pressure appropriate to ambient temperature. Refer to Table 301. NOTE: Admit gas slowly to prevent false readings due to overheating. (4) Close accumulator valve, remove gas rig and evacuate charging connection. B. Check accumulator inflation pressures. (1) Release hydraulic pressure (refer to para 1). (2) For each accumulator, perform the following at the hydraulic servicing panel:- (a) Open appropriate accumulator valve and check that the ACCUMULATOR pressure gauge reads pressure appropriate to ambient temperature. Refer to Table 301. (b) Close accumulator valve and evacuate charging line. C. Inflate the reservoir NOTE: This procedure relates to the initial inflation of the unit i.e. following installation (reservoir empty). Para. D details the 'in service' inflation check procedure under stated aircraft conditions. (1) Refer to , pb301. Provide electrical power. (2) Close C/B No. 36 on distribution panel 1D. (3) Check that needle of CONTENTS gauge on flight compartment panel 7P registers on white line (reservoir empty); if not, press and hold button on BLEED VALVE at the hydraulic servicing panel during the succeeding operation until this occurs. (4) Connect a supply of NITROGEN to the reservoir INFLATION VALVE on the hydraulic servicing panel and charge until RESERVOIR gauge shows pressure relative to ambient temperature. Refer to Table 302 (dry air may be used only in an emergency situation, and the reservoir should be re-charged with nitrogen at the earliest opportunity) Page 303

11 SD3-60 AIRCRAFT MAINTENANCE MANUAL NOTE: Admit gas slowly to prevent false readings due to overheating. TEMP INFLATION PRESSURE 0 F (psig) ) ) ) ) ) ) Table 302- Reservoir Initial Inflation Pressures D. Check reservoir inflation Special tools and equipment:- Hydraulic pressure rig: T (power rig) or *T (hand pump) NOTE: On post-mod 7662 aircraft, main system pressure operationally dissipates to reservoir through a restrictor in the landing gear down lines some 15 seconds after the second engine is shutdown. A handpump * can therefore only effectively be used in the following procedure (without system break-in and restrictor blanking) on those aircraft construction nos. prior to and including SH 3650 on which Service Bulletin SD (Mod 7662) has not been incorporated. (1) Refer to , pb301. Provide electrical power. (2) Ensure C/B No. 36, 54 or 101 (depending on aircraft effectivity) on distribution panel 1D and C/B No. 204 on panel 2D are closed. (3) Perform the following at the hydraulic servicing panel:- (a) Connect hydraulic rig to the GROUND TEST (PRESSURE and RETURN) connectors. (b) Open the SYSTEM accumulator valve and operate rig to slowly raise ACCUMULATOR pressure gauge reading to 3000 psi. (c) Close SYSTEM accumulator valve and evacuate the charging connection. (4) Select FLAPS control lever to 0 and when surfaces come to reset fully in and locked, repeat (3) - (b) and (c) Page 304

12 (5) Open the FLAP accumulator valve at the servicing panel and check that ACCUMULATOR pressure gauge reads 3000 psi. Close valve and evacuate charging connection. (6) Check on flight compartment panel 7P:- (a) That SYSTEM gauge reads ero; if necessary, operate toe brakes repeatedly to comply. (b) That the EMERGENCY WHEELBRAKES and EMERGENCY LANDING GEAR pressure gauges each read 3000 psi. (c) That the pointer on the reservoir CONTENTS gauge is in the centre of the YELLOW sector. (7) Check that RESERVOIR gauge on servicing panel shows inflation pressure relative to ambient temperature. Refer to Table 303. If not, adjust pressure to appropriate value. (8) Disconnect hydraulic rig. 3. Priming and bleeding NOTE: Priming and bleeding of the service systems is dealt with in the appropriate chapters. Special tools and equipment:- TEMP INFLATION PRESSURE 'C 'F (psig) ) ) ) ± ) ) ) Table 303- Reservoir Inflation Check Pressures Hydraulic hand pump rig: Hydraulic replenishment rig: Pressure relay clamp: T T T A. Prime and bleed the power circuit (1) Refer to , pb301. Provide electrical power. (2) Inflate the reservoir (refer to para. 2.C.) Page 305

13 SD3-60 AIRCRAFT MAINTENANCE MANUAL (3) Refer to , pb301. Connect replenishment rig T (with fluid to specification quoted) to the FILL coupling on the hydraulic servicing panel and operate until the pointer on the CONTENTS gauge on panel 7P is in the YELLOW sector. (4) Slacken the connection on the reservoir side of the non-return valve in the right hand pump drain line (centre-section front spar) until air-free fluid is emitted; tighten connection. (5) Repeat (4) at non-return valve in the left pump case drain line. (6) Open pump inlet shut-off valves as follows:- (a) Ensure C/B Nos. 37 and 186 on respective distribution panels 1D and 2D are closed. (b) Select LEFT and RIGHT PUMP INLET VALVE control switches on panel 7P to OPEN. (7) Prime and bleed each pump in turn as follows:- (a) Slacken the inlet flexible hose where attached to pump until air-free fluid is emitted; tighten connection. (b) Disconnect the case drain flexible hose from the pump and, via the case drain connection, fill the pump with clean fluid until all air is excluded. Fill the hose with fluid and with minimum spillage, reconnect to pump. (c) Disconnect the main pressure (pump delivery) flexible hose from the pump; fill the hose with clean fluid and, with minimum spillage, reconnect to pump. (8) Prime the system pressure gauge (refer to para. B). (9) Top up the reservoir. Refer to , pb301. NOTE: The reservoir should be re-bled following the next complete day of operation. B. Prime the system pressure gauge. (1) Connect hand pump rig T to the GROUND TEST (PRESSURE and RETURN) connectors on the hydraulic servicing panel. (2) Slacken connections at the inlet side of the pressure relay and at the gauge. (3) Fit clamp T between the two circumferential grooves on the relay body. NOTE: The clamp should be tightened just sufficient to slightly flex the body and grip the piston, but not enough to cause permanent distortion. (4) Operate the hand pump and tighten the relay inlet gauge connections in turn when airfree fluid is emitted Page 306

14 (5) Remove hand pump rig and relay clamp Page 307

15 AMM RESERVOIR - DESCRIPTION AND OPERATION 1. Description The reservoir, which is pressuried to provide adequate inlet pressure to the engine-driven pumps is mounted laterally across the left side of the fuselage top skin, immediately aft of the wing rear spar. Refer to Figure 1. The unit basically consists of a cylinder which houses a sealed floating piston. The piston divides the unit into two separate chambers, the outboard for hydraulic fluid and the inboard for nitrogen (dry air may be used only in an emergency). The end fitting on the fluid side of the unit incorporates three connections; these provide for (a) system return and unit replenishment, (b) system supply and (c) system bleed. The gas end of the cylinder incorporates an inflation connector. Direct indication of fluid contents is provided by a dial indicator, mounted on the end fitting and connected by a spring-loaded drum and cable assembly to the piston. Rotation of the drum, as the fluid contents vary, is transmitted through a spur gear and drive shaft to the dial indicator which registers reservoir contents. A potentiometer, connected to the drive shaft provides for flight compartment indication. Refer to , pb1. 2. Operation With the nitrogen chamber inflated, fluid pressure is assured at all times and any variation in reservoir fluid content will cause movement of the piston in the cylinder. An increase of fluid content causes the piston to move towards the nitrogen end of the cylinder, pulling the cable to rotate the drum against the torsioned load of the spring. When a demand is made on the system the fluid content decreases and the piston moves in the opposite direction allowing the cable to re-wind as the reaction of the spring rotates the drum. Rotation of the drum is transmitted through the gears and drive shaft to the dial which revolves to indicate the fluid content in cubic inches Page 1

16 SD3-60 AIRCRAFT MAINTENANCE MANUAL Reservoir Figure Page 2

17 AMM RESERVOIR - TROUBLE SHOOTING 1. Trouble Shooting External leakage Fault Possible cause Rectification Defective sealing of:- (a) Housing (b) Spring torsioner (c) End fitting Remove unit and fit a serviceable one. Internal leakage Defective sealing of piston Remove unit and fit a new one Page 101

18 AMM RESERVOIR - MAINTENANCE PRACTICES 1. Servicing Initial inflation. Refer to , pb301. Reservoir replenishment information. Refer to , pb Removal/Installation A. Remove a reservoir (1) Open a circuit breaker No.36 on left distribution panel 1D. (2) Connect a length of suitable tubing to the BLEED DRAIN spout at the bottom of the hydraulic service panel and lead off to a container of approximately 2 US gallons capacity. (3) Press button on BLEED VALVE and hold until flow to container ceases. (4) Open reservoir INFLATION VALVE and release nitrogen pressure. (5) Remove access panel 250 AL on aft fairing, refer to Chap.6. (6) Disconnect electrical lead from rotary potentiometer at T.B.86. (7) Disconnect pipe connections to unit. (8) At inboard end unscrew large nut securing unit to mounting structure. (9) At outboard end unscrew six bolts with washers and two nuts with washers from mounting angle. (10) Withdraw unit. (11) Blank off all pipes and pipe connections. B. Install a reservoir NOTE: Operations (1) and (2) only apply if the unit being installed is not that which was previously removed (para A). (1) Remove unions and gaskets from unserviceable unit. Discard gaskets. (2) Screw unions into replacement unit using new gaskets Part No. MS OFF and MS OFF. Torque tighten and witness mark. Refer to , pb1. (3) Position unit in aircraft with inflation union protruding through hole in inboard end of mounting structure. Fit large nut (leave slack at this stage) Page 201

19 SD3-60 AIRCRAFT MAINTENANCE MANUAL Reservoir - Removal/Installation Figure Page 202

20 (4) Locate outboard mounting angle on the two studs which protrude from the fluid end of the unit and secure each with a nut and washer. (5) Rotate unit to align the mounting angle attachment holes. Fit the six attachment bolts and washers. (6) Tighten nut at inboard end of unit. (7) Remove blanks from pipes and pipe connections. (8) Connect pipes to appropriate connections on unit. (9) Torque tighten and witness mark (Refer to , pb1.). (10) Connect electrical lead from rotary potentiometer to T.B.86. (11) Close circuit breaker No.36 on left distribution panel 1D. (12) Inflate the reservoir as detailed in , pb301. (13) Replenish the reservoir as detailed in , pb301. NOTE: Operation (14) which follows applies to post-mod 7115 aircraft only i.e. those equipped with trimmer adjusters for the flight compartment RESERVOIR CONTENTS indicator. (14) Make any necessary calibration adjustment to the flight compartment RESERVOIR CONTENTS indicator. Refder to , pb201. (15) Install access panel 250 AL on aft fairing Page 203

21 AMM PUMP INLET SHUT-OFF VALVES - DESCRIPTION/OPERATION 1. Description An electrically operated shut-off valve is introduced in the inlet line to each of the engine-driven pumps. The valves (positioned in the wing leading edge inboard of the engine) are employed to terminate the flow of hydraulic fluid from the reservoir to the pump in the event of an engine fire. The valve actuators have 'open' and 'close' fields and incorporate limit switches to prevent overtravel. An indicator module for each valve, forming part of the hydraulic diagram on panel 7P, is controlled by the limit switches. The valves, idented 1GA2 and 2GA2 (left and right respectively) are controlled by PUMP INLET OPEN/SHUT switches on panel 7P; each switch is subject to the overriding authority of a microswitch operated by the relevant engines L.P. fuel valve control lever on the flight deck roof console. NOTE: The microswitches at the L.P. fuel valve control levers ensure closure of the appropriate shut-off valve during engine fire drill. 2. Operation To open a valve, ensure the appropriate L.P. fuel valve control lever is secured in its forward OPEN position and the control switch on panel 7P is selected ON. 28V d.c. will then be made available via the microswitch at the L.P. fuel valve lever to the 'open' field of the valve actuator. When fully open, the valve actuator limit switches trip to arrest actuator travel and provide open indication. The valve will close if either the control switch on 7P or the L.P. fuel valve lever on the roof console is selected SHUT: thus energising the 'close' field of the valve actuator. When fully closed, the limit switches again trip to arrest actuator travel and provide closed indication Page 1

22 AMM INLET SHUT-OFF VALVE - MAINTENANCE PRACTICES 1. Removal/Installation A. Remove a shut-off valve (1) Deflate hydraulic reservoir. Refer to , pb301. (2) Open circuit breaker No.37 on left distribution panel 1D and circuit breaker No.186 on right distribution panel 2D. (3) Gain access to shut-off valves through access panels 510AB and 510FT (one 500) in inner wing (left) and access panels 610AB and 610FT (one 600) in inner wing (right) (4) Disconnect electrical plug from receptacle on valve body, (5) Disconnect pipe connection to shut-off valve body. (6) Disconnect pipe connection to Tee-connector attaching the shut-off valve to wing rib at stn (7) Undo nut attaching Tee-connector to wing-rib at stn (8) Withdraw shut-off valve, complete with Tee-connector from the aircraft. (9) Blank off hydraulic pipe connections. B. Install a shut-off valve NOTE: Operations (1) to (3) only apply if the unit being installed is not that which was previously removed (para A) (1) Remove Tee-connector and gasket from unservicable unit. Discard gasket. (2) Screw the replacement shut-off valve into the Tee-connector, using a new gasket (Part No MS ) interposed between the shut-off valve body and the mating face of the Tee-connector. NOTE: Ensure that the Tee-connector is attached to the shut-off valve at the connection remote from the electrical plug receptacle. (3) Arrange to have the blanked off connection of the Tee-connector approximately vertically below the body of the shut-off valve. (4) Ensure that circuit breakers No.37 on left distribution panel 1D and No.186 on right distribution panel 2D are open. (5) Gain access to shut-off valve positions, either through access panels 510AB and 510FT (one 500) in inner wing (left) or access panels 610AB or 610FT (one 600) in inner wing (right) Page 201

23 SD3-60 AIRCRAFT MAINTENANCE MANUAL (6) Remove blanking plugs from pipe ends. (7) Install shut-off valve and Tee-connector assembly into the wing, attaching the Teeconnector to wing rib at stn with single attachment nut and washer (on Teeconnector side or rib). (8) Re-connect pipes to shut-off valve body and end of Tee-connector and torque tighten nuts. Refer to , pb1. (9) Re-connect bayonet-type electrical plug to shut-off valve body. (10) Close access panels. (11) Close circuit breakers, No.37 on left distribution panel 1D and No.186 on right distribution panel 2D. (12) Replenish reservoir and reflate. Refer to , pb Adjustment/Test A. Function check the shut-off valve. (1) Refer to , pb301. Provide electrical power. (2) Close circuit breakers, No.37 on left distribution panel 1D and No.186 on right distribution panel 2D. (3) Select LEFT PUMP INLET VALVE control switch on panel 7P to OPEN, noting that the associated indicator module on panel 7P shows the valve 'on line' (open). (4) Select LEFT PUMP INLET VALVE control switch on panel 7P to SHUT noting that the associated indicator module shows the valve 'off line' (shut). (5) Re-select LEFT PUMP INLET VALVE control switch on panel 7P to OPEN, noting that the associated indicator module shows the valve 'on line' (open). (6) Free securing wire and select LEFT ENGINE L.P. VALVE control lever on roof console to the aft SHUT position, and note that LEFT PUMP INLET VALVE indicator module shows the valve 'off line' (shut). (7) Repeat operations (3) to (6) inclusive for the RIGHT PUMP INLET VALVE, reading right for left. (8) Place L.P. VALVE control levers in OPEN position and re-attach securing wires Page 202

24 B. Adjust the microswitches. Special tools and equipment:- Continuity Tester (1) Open C/B Nos. 37 and 186 on respective distribution panels 1D and 2D. (2) Gain access to the microswitches 1GA6, 2GA6 and terminal block TB 54 by removing the aft section of the roof console bottom cover assembly. (3) Rig each microswitch in turn as follows:- (a) Slacken the slotted nut at the top of the microswitch mounting plate and pivot the assembly aftwards. (b) Free securing wire and select the engine L.P. shut off valve lever to the SHUT position. (c) Slowly pivot the microswitch assembly forward until the switch operates i.e. continuity between switch associated terminals on TB 54 is achieved. Refer to Table 201. LEFT L.P. SHUT OFF VALVE SWITCH (d) Tighten the slotted nut and lock with split pin. (e) Check that continuity is broken when the lever is removed from the SHUT gated position. (4) Attach aft section of roof console bottom cover assembly. (5) Return engine L.P. shut off valve levers to OPEN position and re-attach securing wire. L.P. VALVE LEVER SHUT POSITION CONTINUITY CHECK AT TB 54 L.P. VALVE LEVER OPEN POSITION RIGHT L.P. SHUT OFF VALVE SWITCH L.P. VALVE LEVER SHUT POSITION CONTINUITY CHECK AT TB 54 Engine L.P. shut off valve microswitches - continuity checks Table 201 L.P. VALVE LEVER OPEN POSITION TERM LS TERM LS TERM LS TERM LS 1GA6 YES (4 & 6) No (4 & 6) 2GA6 YES (1 & 3) No (1 & 3) Page 203

25 AMM HIGH PRESSURE RELIEF VALVE - DESCRIPTION/OPERATION 1. Description Refer to Figure 1. The high pressure relief valve is employed to substantially reduce pump delivery pressure and thus prevent excessive heat generation should the pump pressure compensating facility become unserviceable during running. The unit basically consists of a body which incorporates an inlet and an outlet adapter and houses a lapped valve plunger and sleeve assembly. The valve plunger accommodates a further lapped plunger and is loaded by a spring. The degree of spring loading, determines the pressure at which the valve will operate; it is set by an adjuster bolt which is enclosed by an end cap. A smaller bore in the valve body, housing a restrictor and filter, connects the end of the sleeve bore with the valve outlet. 2. Operation Refer to Figure 2. When the system is working normally, fluid pressure from the pump is constantly applied to the inlet connection and is felt on face 'Z' of the valve plunger bore. Should there be any fluid seepage between the plunger and the valve plunger or between the valve plunger and the sleeve, the fluid is able to escape to return via the restrictor. The restrictor prevents a pressure build-up in the valve when the valve is closed and ensures that there is no appreciable drop in pressure when the valve is open; the restrictor hole is protected by a filter to prevent blockage. Any seepage from the other end of the valve plunger is able to escape through a hole in the retainer. Should inlet pressure rise to psi., the additional force applied at face 'Z' of the valve plunger will be sufficient to overcome the spring loading and the plunger will move against the spring. As the plunger moves, a chamfer on land 'X' will gradually clear the bore of the sleeve allowing a progressive application of pressure to the rear face of the plunger. The force applied to this face supplements that already acting on face 'Z' to continue moving the plunger until land 'Y' clears the bore and opens a passage from the inlet to the outlet connection. When the valve operates it will not return to the closed position whilst there is flow through the unit i.e. the engine-driven pump continues to run. When operated, the relief valve will drop the pump output pressure to approximately 450 psi. 3. Data Inlet connection Outlet connection Relief pressure 9/16 in UNF. 3/4 in UNF psi Page 1

26 SD3-60 AIRCRAFT MAINTENANCE MANUAL Cut-away view of relief valve Figure Page 2

27 Operation Figure Page 3

28 AMM HIGH PRESSURE RELIEF VALVE - TROUBLE SHOOTING 1. Trouble shooting Fault Possible Cause Rectification Valve relieves below set pressure External leakage Incorrect setting of valve Adaptors and/or plugs insufficiently tightened Failure of seal(s) Remove and test in accordance with unit Overhaul Manual (Automotive Products - AIR 87224) Tighten Renew faulty seal(s) Page 101

29 AMM HIGH PRESSURE RELIEF VALVES (PT. NO. AIR87224) - MAINTENANCE PRACTICES 1. Removal/Installation A. Remove a valve (1) Note reservoir inflation pressure and depressurie. (2) Gain access to relief valve left or right respectively, by removing access panel 240NL or 240NR. (3) Disconnect both hydraulic pipes and suitably cover open pipe ends. (4) Remove and retain two bolts, washers and nuts. (5) Remove valve from mounting brackets. B. Install a valve (1) Install valve in mounting brackets and secure with two bolts, washers and nuts. Torque tighten bolts. Refer to , pb1. (2) Remove covers from pipes. (3) Reconnect both hydraulic pipes. Do not tighten unions at this stage. (4) Inflate and maintain reservoir pressure at 15 p.s.i. and tighten MR pipe union when airfree fluid is emitted. (5) Refer to , pb1. Torque tighten both hydraulic pipe unions and apply witness mark. (6) Inflate reservoir to pressure noted in 1.A.(1). (7) Refit access panel. 2. Adjustment/Test A. Function check Special tools and equipment Hydraulic hand pump rig: T (1) Check for the following system conditions:- (a) Landing gear - down and locked (b) Flaps - fully up Page 201

30 SD3-60 AIRCRAFT MAINTENANCE MANUAL (2) Connect the suction line of the hand pump rig to the GROUND TEST RETURN connector on the hydraulic servicing panel in the rear of the left main gear fairing. (3) Ensure that MAIN SYSTEM pressure gauge on panel 7P reads ero. (4) Disconnect the MP line from the left or right pump as appropriate to valve unit under test and connect rig pressure line to the system MP line. NOTE: Step (5) which follows applies to aircraft Ser. Nos SH3651 and up and those prior Ser. Nos on which Serv. Bull. SD is incorporated. (5) Refer to , Figure 201 Remove restrictor pipeline and plug unions. (6) Operate the hand pump and raise pressure slowly checking that the relief valve operates at psi. Stop pumping. NOTE: When the relief valve operates, rig-indicated pressure should fall to below 500 psi. (7) Check that the valve has reseated by resuming pumping and raise rig-indicated pressure to 1000 p.s.i. (8) Off-load MAIN SYSTEM pressure by operating the wheelbrakes and disconnect the rig. (9) Reduce pressure in the landing gear emergency, emergency brake, and flap system accumulators to 3000 psi. (10) If step (5) was applicable, refit restrictor pipeline previously removed Page 202

31 AMM RELIEF VALVE (L.P. GAS) - MAINTENANCE PRACTICES 1. Routine servicing A. General (1) Before commencing routine checks, remove all dirt and foreign matter from the unit. (2) Check for any visible signs of fracture, corrosion or other damage. (3) Check that the unit is secure. (4) Check for external signs of damage. 2. Removal/Installation A. Remove a relief valve (1) Gain access to relief valve through access panel in aft wing fairing, number 250AL (one 200). (2) Release the nitrogen pressure in the reservoir. (3) Undo two nuts retaining the relief valve in the pipe line between the reservoir and the inflation tee-piece. (4) Remove relief valve, and blank off the unit and pipe ends. B. Install a relief valve (1) Open access panel in aft wing fairing, number 250AL (one 200). (2) Remove blanking plugs from pipe ends and relief valve. (3) Install in pipe line between reservoir and inflation tee-piece. (4) Torque tighten nuts. Refer to , pb1. (5) Re-pressurise reservoir. (6) Close access panel, 250AL Page 201

32 SD3-60 AIRCRAFT MAINTENANCE MANUAL 3. Adjustment/Test A. Function check the relief valve Special Tools and Equipment:- Trolley, Nitrogen: T (1) Connect a length of suitable tubing to the BLEED DRAIN spout at the bottom of the hydraulic service panel and lead off to a container of approximately 2 U S gallons capacity. (2) Press BLEED VALVE button on the hydraulic servicing panel and hold until flow to container ceases. (3) Refer to , pb301. Provide electrical power. (4) Close C/B No.36 on distribution panel 1D. (5) Check that needle of CONTENTS gauge on flight compartment panel 7P registers on white line below red arc (reservoir empty); if not, press and hold the BLEED VALVE button on the servicing panel during the succeeding operation until this occurs. (6) Connect a supply of nitrogen to the reservoir INFLATION VALVE on the servicing panel, admit gas and raise pressure slowly, checking that when the RESERVOIR gauge reads psi, the needle immediately falls to 120 psi (indicating that the relief valve has functioned correctly). NOTE: To avoid damage to reservoir in the event of failure of relief valve to operate, do not exceed an inflation pressure of 150 psi. (7) Reduce nitrogen pressure to that associated with ambient temperature (reservoir empty). Refer to Table 201. TEMP INFLATION PRESSURE C F (psig) ) ) ) ) ) ) Inflation Pressure - Reservoir Empty Table 201 (8) Replenish the reservoir. Refer to , pb Page 202

33 (9) Disconnect nitrogen rig. 4. Cleaning/Painting A. Painting Restore any damaged paint surface using Cellon etch primer SL4853 and finishing coat SL5459, colour light grey Page 203

34 AMM RELIEF VALVE (L.P. FLUID) - TROUBLE SHOOTING 1. Trouble Shooting Fault Cause Remedy External leakage Defective O ring Remove adapter, renew O ring Internal leakage Defective valve seat Remove unit, fit a new one NOTE: Should it be necessary to renew seals - reference should be made to Dowty Rotol Overhaul Manual, Ref Page 101

35 AMM RELIEF VALVE (L.P. FLUID) - MAINTENANCE PRACTICES 1. Routine servicing A. General (1) Before commencing routine checks, remove all dirt and foreign matter from the unit. (2) Check for any visible signs of fracture, corrosion or other damage. (3) Check that the unit is secure. (4) Check for external signs of damage. 2. Removal/Installation A. Remove a relief valve (1) Gain access to relief valve through access panel in forward wing fairing, number 240NR (one 200). (2) Deflate hydraulic reservoir. (3) Undo two nuts retaining the relief valve in the pipe line between the reservoir and the overboard pipe. (4) Remove relief valve, and blank off the unit and pipe ends. B. Install a relief valve (1) Open access panel in forward wing fairing, number 240NR (one 200). (2) Remove blanking plugs from pipe ends and relief valve. (3) Install in pipe line between reservoir and overboard pipe. (4) Torque tighten nuts. Refer to , pb1. (5) Reflate hydraulic reservoir. Refer to , pb301. (6) Close access panel 240NR Page 201

36 SD3-60 AIRCRAFT MAINTENANCE MANUAL 3. Adjustment/Test A. Function check the relief valve Special Tools and Equipment: Trolley, Nitrogen: Rig, hydraulic pressure (manual): Rig, hydraulic replenishment: T T T (1) Deflate the reservoir (2) Provide electrical power. Refer to , pb301.) (3) Close C/B No.36 on distribution panel 1D. (4) Connect replenishment rig to the reservoir FILL connection on the hydraulic servicing panel. (5) Charge reservoir until CONTENTS gauge on flight compartment panel 7P registers on white line below yellow arc (reservoir full). Disconnect rig. (6) Connect the pressure line of the hand pump pressure rig to the GROUND TEST RETURN connection on the servicing panel. NOTE: Do not operate rig at this stage. (7) Tape a plastic bag around the overboard discharge pipe outlet (located on the right side of the fuselage roof fairing, approximately 10 in. forward of the wing front spar). NOTE: The bag is employed to collect the small discharge of fluid when the valve is subsequently operated. (8) Operate hand pump rig and raise pressure slowly, checking that when the rig gauge reads psi., the needle immediately falls to 120 psi. (indicating that the relief valve has functioned correctly). CAUTION: TO AVOID DAMAGE TO RESERVOIR IN THE EVENT OF FAILURE OF RELIEF VALVE TO OPERATE, DO NOT EXCEED A RIG INDICATED PRESSURE OF 150 PSI. (9) Remove bag from overboard outlet. (10) Disconnect hand pump rig. (11) Connect nitrogen trolley to the reservoir INFLATION VALVE on the servicing panel and charge until RESERVOIR gauge shows pressure relative to ambient temperature (reservoir full). Refer to Table Page 202

37 NOTE: Admit gas slowly to prevent false reading due to overheating. Table 201 (12) Connect a length of suitable tubing to the BLEED DRAIN spout at the bottom of the servicing panel and lead off to a container of approximately 2 US gallons capacity. (13) Press BLEED VALVE button on the servicing panel and bleed the reservoir until the CONTENTS gauge on flight compartment panel 7P reads within lower half of green sector. Release button. (14) Replenish the reservoir. Refer to , pb301. (15) Disconnect nitrogen rig. 4. Cleaning/Painting A. Painting TEMP INFLATION PRESSURE C F (p s i g ) ) ) ) ) ) ) Restore any damaged paint surfaces, using Cellon etch primer SL4853 and finishing coat, SL5459, colour light grey Page 203

38 AMM SYSTEM ACCUMULATOR - DESCRIPTION/OPERATION 1. Description A. General The accumulator contains a reserve supply of system fluid pressurised by a nitrogen charge to supplement the pump supply. This reserve of fluid is released when a demand is created by the operation of services in order to maintain the system pressure and flow at operating level, and dampen any sudden pressure surges. B. Details 2. Operation Refer to Figure 1. The unit consists of a cylinder, closed at each end by an end fitting, and contains a piston which is free to sweep the internal length. The piston is suitably sealed and divides the unit into two chambers, each of which is marked with its pressure medium, i.e. GAS or FLUID; a tapped hole in each end permits the introduction of the medium. The unit is connected to the system delivery line and the gas chamber is pressurised to a predetermined figure. When the hydraulic system is pressurised, fluid enters the fluid chamber, causing the piston to move, resulting in a further compression of the gas charge; the degree of compression being proportional to the initial inflation figure. When a service is operated, the pressure in the fluid chamber falls, thus allowing the piston to move under gas pressure, thereby forcing the fluid into the system to maintain the operating pressure. On completion of actuation of the service, the momentary rise in pressure in the system is absorbed by the recompression of the gas Page 1

39 SD3-60 AIRCRAFT MAINTENANCE MANUAL System Accumulator Figure Page 2

40 AMM SYSTEM ACCUMULATOR - TROUBLE SHOOTING 1. Trouble Shooting NOTE: Where dismantling is required for renewal of sealing rings, reference should be made to Dowty Rotol Overhaul Manual Fault Cause Remedy Loss of nitrogen pressure Defective seal on end fitting Remove unit, renew sealing ring Defective seal on piston Remove unit, renew sealing ring External fluid leakage Defective seal on end fitting Remove unit, renew sealing ring Fluid leakage past piston Defective seal on piston Remove unit, renew sealing rings Page 101

41 AMM SYSTEM ACCUMULATOR - MAINTENANCE PRACTICES 1. Servicing Refer to , pb Inspection/check NOTE: Before commencing checks - remove all dirt and foreign matter from the unit. A. Inspect the unit (1) Check for any visible signs of fracture, corrosion or other damage. (2) Check that the unit and locking wire are secure. (3) Check for external signs of leakage. 3. Cleaning/painting A. Painting Restore any damaged paint surfaces, using Cellon etch primer SL 4853 and finishing coat SL 5459, colour light grey Page 201

42 AMM LANDING GEAR EMERGENCY ACCUMULATOR - DESCRIPTION/OPERATION 1. Description A. General The unit stores a reserve supply of pressurised fluid for emergency operation of the nose and main landing gear; the fluid being released into the service line through a manually-operated selector mounted on the fluid end of the accumulator. The fluid reserve is replenished, on the restoration of the normal system supply, by the manual operation of the selector valve. B. Details 2. Operation Refer to Figure 1. The cylindrical body is closed at each end by a sealed end fitting and is suitably marked at each end with the appropriate pressure medium, i.e. FLUID or GAS. Housed in the cylinder is a sealed dome piston that divides it into two chambers and is free to sweep its internal length. Drillings from the head of the piston to its waist ensures that it is lubricated during its stroke. Mounting on the fluid end fitting is the selector valve which incorporates a spring-loaded non return valve at right angles to a spring-loaded poppet valve and guide. Attached to the selector body is an operating lever, the heel of which is in contact with a spring-loaded push rod. With the GAS side of the accumulator fully pressurised with nitrogen, fluid pressure entering through connection P lifts the non-return valve off its seat and passes into the fluid side of the accumulator causing the piston to move. This movement results in further compression of the nitrogen charge; the degree of compression being proportional to the initial charging figure. Should there be a fall off or failure of fluid pressure at connection P, back pressure from the accumulator will close the non-return valve, thus preventing the escape of the accumulator fluid. Refer to , pb1. When a landing gear emergency down selection is made, the accumulators selector lever is operated to move the push rod, which in turn lifts the poppet valve off its seat to permit the stored fluid pressure to enter the landing gear emergency down lines via connection 'S'. The unit is fluid re-charged when the landing gear emergency lowering lever is returned to its normal position and normal system pressure is re-established at connection 'P' Page 1

43 SD3-60 AIRCRAFT MAINTENANCE MANUAL Landing Gear Emergency Accumulator Figure Page 2

44 AMM LANDING GEAR EMERGENCY ACCUMULATOR - TROUBLE SHOOTING 1. Trouble Shooting NOTE: Where dismantling is required for renewal of seals, reference should be made to Dowty Rotol Overhaul Manual Loss of gas pressure External fluid leakage Internal fluid leakage Fault Cause Remedy Malfunctioning of nonreturn valves or push rods Defective sealing ring on end Remove unit, renew sealing ring fitting Defective seal pack on piston Remove unit, renew seal pack Defective sealing ring on end Remove unit, renew sealing ring fitting Defective face seal on selector Remove unit and remove selector, renew face seal Defective sealing of push rod Remove unit and remove selector. Fit new selector Defective sealing of valve Remove unit and remove selector. Fit new selector Defective sealing of selector end plug Defective sealing of valve guide Dirt under valve seats or defective springs Remove unit and remove selector. Fit new selector Remove unit and remove selector. Fit new selector Remove unit and remove selector. Fit a new selector Page 101

45 AMM LANDING GEAR EMERGENCY ACCUMULATOR - MAINTENANCE PRACTICES 1. Servicing Refer to , pb Adjustment/Test A. Function test the unit. Extend the landing gear under emergency pressure. Refer to , pb Page 201

46 AMM ACCUMULATOR (EMERGENCY BRAKES) - MAINTENANCE PRACTICES 1. Servicing Refer to , pb Adjustment/Test A. Function check the operating lever. The accumulators integral operating lever is proved functional by the satisfactory completion of brake system operation test. Refer to , pb201. Emergency operation is also detailed Page 201

47 AMM FLAP SYSTEM ACCUMULATOR - DESCRIPTION & OPERATION 1. Description A. This unit provides a 'back up' supply of pressurised fluid to ensure maintenance of a flaps down position (for a limited period) in the event of a main system failure. The fluid reserve is automatically replenished on restoration of the normal system supply. B. Details 2. Operation Refer to Figure 1. The cylindrical body is closed at each end by a sealed end fitting and is suitably marked at each end with the appropriate pressure medium, i.e. FLUID or GAS. Housed in the cylinder is a sealed domed piston that divides it into two chambers and is free to sweep its internal length. Drillings from the head of the piston to its waist ensure that it is lubricated during its stroke. Mounting on the fluid end fitting is a valve unit which incorporates a spring-loaded non-return valve housed in an adapter. A distance piece in the main bore of the unit is retained by a sealed end plug. With the GAS side of the accumulator fully pressurised, fluid pressure entering the unit at connection P lifts the non-return valve off its seat and passes to the fluid side of the accumulator, causing the piston to move. This movement results in further compression of the gas charge; the degree of compression being proportional to the initial charging figure. Should there be a fall off or failure of fluid pressure at connection P, back pressure from the accumulator will close the non-return valve, thus preventing the escape of the accumulator fluid. With the re-establishment of normal system pressure at connection P, the non-return valve is lifted off its seat to permit the re-charging of the accumulator Page 1

48 SD3-60 AIRCRAFT MAINTENANCE MANUAL Flap System Accumulator Figure Page 2

49 AMM FLAP SYSTEM ACCUMULATOR - TROUBLE SHOOTING 1. Trouble Shooting NOTE: Where dismantling is required for renewal of seals, reference is to be made to Dowty Rotol Manual Loss of gas pressure External fluid leakage Fault Cause Remedy Malfunctioning of nonreturn valve Defective sealing ring on end fitting Defective seal pack on piston Defective sealing ring on end fitting Defective face seal on valve unit Defective sealing of valve unit end plug Dirt under valve or defective spring Remove unit, renew sealing ring Remove unit, renew seal pack Remove unit, renew sealing ring Remove unit, remove valve unit, renew face seal Remove end plug, renew sealing ring Remove valve unit. Fit a new valve unit Page 101

50 AMM FLAP SYSTEM ACCUMULATOR - MAINTENANCE PRACTICES 1. Servicing Refer to , pb Removal/Installation WARNING: RELEASE HYDRAULIC OIL AND NITROGEN PRESSURE BEFORE REMOVAL. A. Remove an accumulator (1) Gain access to accumulator by removing access panels 250BR and 250AR. Refer to , pb1. (2) Ensure that MAIN SYSTEM pressure reads ero. (3) Open circuit breaker No. 185 on distribution panel 2D. (4) Open FLAP accumulator valve at hydraulic service panel and evacuate nitrogen at INFLATION VALVE. (5) Disconnect GAS and FLUID pipes at accumulator. Suitably cover open pipes. NOTE: Identify hydraulic pipe couplings i.e. 'IN' and 'OUT' for subsequent installation. (6) Release both clamps and remove accumulator from mounting brackets. B. Install an accumulator (1) Install accumulator in mounting brackets with GAS connection outboard. Fit clamps. NOTE: Do not fully tighten clamps at this stage. (2) Remove covers from pipe ends and reconnect to accumulator. Fully tighten clamps. (3) Refer to , pb1. Torque tighten GAS coupling in accordance and apply witness mark. (4) Inflate the FLAP accumulator. Refer to , pb301. (5) Connect hydraulic pump to PRESSURE and RETURN connections on hydraulic service panel. Operate hand pump until air-free fluid is emitted at both accumulator hydraulic pipe connections. (6) Torque tighten hydraulic FLUID couplings in accordance with and apply witness mark. (7) Connect hydraulic power rig, raise system pressure to psi and check accumulator for leaks Page 201

51 SD3-60 AIRCRAFT MAINTENANCE MANUAL (8) Check hydraulic fluid CONTENTS (panel 7P) and replenish if necessary. (9) Refit access panels. Refer to , pb1. (10) Perform function test of flap system accumulator. Refer to , pb Adjustment/Test A. Function test the integral check valve. Special tools and equipment Hydraulic power rig: T (1) Connect hydraulic rig to GROUND TEST CONNECTORS (PRESSURE and RETURN) on the hydraulic servicing panel in the rear of the left main landing gear fairing. (2) Raise SYSTEM pressure (panel 7P) to 3000 ± 100 psi. (3) Open FLAP accumulator valve (hydraulic servicing panel) and check that pressure shown on inflation check gauge reads 3000 ± 100 psi. (4) Check that accumulator pressure remains at 3000 ± 100 psi for a minimum period of 10 minutes. (5) Close FLAP accumulator valve (servicing panel). (6) Disconnect rig Page 202

52 AMM SOLENOID SELECTOR (FLAP SYSTEM) - MAINTENANCE PRACTICES 1. Adjustment/Test A. Function test the unit Special tools and equipment:- Hydraulic power rig: T (1) Refer to , pb301. Provide electrical power. (2) Connect hydraulic rig to GROUND TEST CONNECTORS (PRESSURE and RETURN) on the hydraulic servicing panel in the rear of the left main landing gear fairing. (3) Raise SYSTEM pressure (panel 7P) to 3000 ±100 psi and select flaps fully up. (4) Open FLAP accumulator valve (hydraulic servicing panel) and check that pressure shown on inflation check gauge reads 3000 ±100 psi. (5) Stop hydraulic power rig and off-load system pressure. NOTE: On early production aircraft it may be necessary to repeatedly operate wheelbrakes to off-load the pressure. (6) Open CB No.185 on right distribution panel 2D. (7) Select 5 deg. flap and check that there is no response from surfaces (selector closed). Return control lever to 0 deg. position. (8) Close CB No.185 and again select 5 deg. flap and check that the surfaces move to the selected position (selector valve energised open). NOTE: Also check that the accumulator pressure remains at 3000 ±100 psi. (9) Disconnect rig Page 201 Dec 18/07

53 AMM CHECK VALVE (FLAP SYSTEM) - MAINTENANCE PRACTICES 1. Adjustment/Test Special tools and equipment:- Hydraulic power rig: T A. Function check (1) Refer to , pb301. Provide electrical power. (2) Close C/B No. 185 on right distribution panel 2D. (3) Connect hydraulic rig to GROUND TEST CONNECTORS (PRESSURE and RETURN) on the hydraulic servicing panel in the rear of the left main landing gear fairing. (4) Raise SYSTEM pressure (panel 7P) to 3000 ± 100 psi and select flaps fully 'up'. Stop power rig. (5) Open FLAP accumulator valve (hydraulic servicing panel) and check that pressure shown on inflation check gauge reads 3000 ± 100 psi. (6) Check SYSTEM pressure falls to ero. NOTE: On early production aircraft it may be necessary to repeatedly operate wheelbrakes to off-load system pressure. (7) Stage extend flaps to the fully down position and note that the SYSTEM pressure gauge reading remains steady at ero (this will confirm the check valve functional). (8) Close FLAP accumulator valve. (9) Disconnect rig Page 201

54 AMM CHECK VALVE (PUMP CASE DRAIN LINES) - MAINTENANCE PRACTICES 1. Adjustment/Test A. Function check (1) Check that an indicated pressure of not less than 30 psi. is registered on the RESERVOIR pressure gauge on the hydraulic servicing panel (located in the rear of the left main gear fairing). (2) Disconnect the pump case drain line (LPCD or RPCD as appropriate) from the associated pump and check that there is no sustained flow from the pipe. (3) Reconnect line to pump Page 201

55 AMM CHECK VALVE (PUMP MP LINES) - MAINTENANCE PRACTICES 1. Adjustment/Test A. Function check (1) Start opposite engine. Refer to , pb1. (2) Check that the display condition of the HYD low pressure warning lights (amber) on panel 1P are as follows:- Running engine: Stopped engine: extinguished illuminated (check valve functional) Page 201

56 AMM HYDRAULIC PUMP - MAINTENANCE PRACTICES 1. Removal/Installation A. Remove a hydraulic pump. (1) Ensure that the relevant engine L.P. fuel control lever on the flight deck roof console is in the 'SHUT' position. (2) Remove access panel 410AL on power plant. Refer to , pb1. (3) Disconnect flexible hoses and blank off open connections. (4) Remove locking wire, support the pump and remove the securing nuts. (5) Disengage shaft splines and remove pump. Discard gasket. CAUTION: ENSURE THAT THE WEIGHT OF THE PUMP IS NOT TAKEN BY THE SHAFT. (6) Blank off engine. B. Install a hydraulic pump NOTE: Operations (1) and (2) only apply if the unit being installed is not that which was previously removed (para A). (1) Remove unions and sealing rings from unserviceable unit. Discard sealing rings. (2) Fit the undernoted unions (retained) and new sealing rings to appropriate ports on replacement pump. Torque tighten and witness mark. Refer to , pb1. UNIT PORT UNION SEALING RING Inlet AN815-8C AS Outlet AN815-6C AS Case Drain AN AS Seal Drain AN815-4K AS (3) Fit new gasket to face of fixing flange on engine. (4) Lubricate the splines on the pump shaft and quill shaft with clean engine oil. Refer to , pb1. CAUTION: ENSURE THAT THE WEIGHT OF THE PUMP IS NOT TAKEN BY THE SHAFT. (5) With the case drain connection uppermost, align the pump shaft and slide pump into position Page 201

57 SD3-60 AIRCRAFT MAINTENANCE MANUAL (6) Lubricate stud threads with engine oil and secure pump in position with four nuts and washers. Torque tighten securing nuts to 54 lbs.in. and wire lock. (7) Connect 'Case Drain' and 'Main Pressure' hoses to appropriate connections on pump. Torque tighten and witness mark. Refer to , pb1. (8) Connect 'Inlet' hose to appropriate connection on pump but do not fully tighten. CAUTION: AVOID ANY TWISTING OR TENSIONING OF FLEXIBLE HOSES DURING CONNECTION. ALLOW EACH HOSE TO TAKE UP POSITION OF RELAXED ALIGNMENT AND MAINTAIN THIS CONDITION WHEN SUBSEQUENTLY TIGHTENING CONNECTIONS FOLLOWING PRIMING AND BLEEDING OPERATIONS. (9) Prime and bleed pump and associated lines as follows:- (a) Refer to , pb301. Provide electrical power. (b) Open appropriate pump inlet shut-off valve as follows:- 1 Left Installation: close circuit breaker No. 37 on Panel 1D. Right Installation: close circuit breaker No. 186 on Panel 2D. 2 Select appropriate ENGINE L.P. VALVE control lever in flight compartment roof console to forward OPEN position. 3 Select appropriate PUMP INLET VALVE control switch on Panel 7P to OPEN. (c) Slacken inlet hose where attached to pump until air-free fluid is emitted, then torque tighten hose connection and witness mark. (d) Close pump inlet valve as follows:- 1 Select control switches on Panel 7P to SHUT. 2 Return ENGINE L.P. VALVE control lever to SHUT position. (10) Reconnect seal drain hose to pump, torque tighten and witness mark. (11) Install access panel 410AL on power plant. (12) Replenish reservoir. Refer to , pb301. (13) Perform function check as detailed in para Adjustment/Test A. Function check a pump (1) Start the appropriate engine. Refer to , pb Page 202

58 (2) Check the following: (a) Relevant HYD warning light on centralied warning panel is extinguished. (b) That the system pressure stabilies at psi. (3) With the engine at 'Flight Idle' RPM operate the flaps checking that the operating time from 35 to 0 is not more than 26 ± 2 seconds. (4) Check pump noise for irregularity of pitch (indicative of malfunction). (5) Shutdown engine. (6) Lower intake cowl and check that the end of the pump seal drain pipe (most forward of group housed within drain mast on cowl) does not display evidence of oil leakage Page 203

59 AMM FILTERS - MAINTENANCE PRACTICES 1. Servicing A. Change a filter element. Special Tools and Equipment:- Seal manipulating tools (set of three): T (1) Gain access to filters through the undernoted access panels:- Panel No. Location Filter Type (Fairey) Alternative (APME) 240 NL Wing Centre Section Front Spar (Fwd.) 240 NR Wing Centre Section Front Spar (Fwd.) 730 MT Main Landing Gear Fairing (Left) (2) Release system pressure. Refer to , pb301. (3) Note reservoir inflation pressure, and then deflate. (4) Remove locking wire, securing head to body. (5) Unscrew and lower the body, carefully removing the element from the head spigot. (6) Drain element and inspect for contamination. NOTE: If level of contaminant is abnormal, a further check of the system components should be made to ascertain the cause. (7) Obtain replacement or clean element as detailed in para 2.A. NOTE: The element of filter unit 3727 H1 (fibre glass) is to be discarded. (8) Using seal manipulating tool T , remove head to body seal, cut and discard. (9) Carefully remove the seal backing ring and examine for damage. NOTE: It should not be necessary to fit a new backing ring unless damaged, but when a new ring is used it is to be slit as indicated in the relevant Fairey Filter Maintenance Manual immediately prior to assembly. (10) Wash the body in clean system fluid H2 (pressureline) QA H1 (return line) QA H2 (system charge line) QA 0808 NOTE: Prior to fitting new seals, remove all traces of french chalk and lightly smear with clean system fluid Page 201

60 SD3-60 AIRCRAFT MAINTENANCE MANUAL (11) Examine element to be replaced for signs of damage and fit new element-to-head seal. (12) Fit a new head-to-body seal to the head, together with the existing backing ring (or if damaged a new ring) ensuring the backing ring is fitted to the atmosphere side of the seal). (13) Insert element into head to engage the head spigot and screw onto the body hand tight, wire locking to filter head. (14) Reset the indicator button with light finger pressure. (15) Refer to , pb301. Top up reservoir and inflate to pressure noted during operation (3). (16) Over a period of four minutes, check that the indicator button on the affected filter unit remains housed, and that there is no leakage from connections. NOTE: For pressure line filter unit it will be necessary to raise system pressure to 3000 p.s.i. B. Check operation of DPI and Bypass valve (return line filter 3727 H1 or QA0936) Special Tools and Equipment:- Element Blank for 3727 H1 filter: T (1) Gain access to filter through access panel number 240 NL located in the wing centre section at the front spar. (2) Release system pressure. Refer to , pb301. (3) Note reservoir inflation pressure, and then deflate. (4) Disconnect inlet and outlet connections to the filter assembly. (5) Remove locking wire securing head to body. (6) Unscrew and lower the body, carefully removing the element from the head spigot. (7) Re-assemble filter unit with element blank T fitted in place of element. (8) Connect handpump with a suitable pressure gauge to the inlet side of the filter unit, leaving the outlet open to atmosphere. (9) Apply pressure and check that DPI button indicates within p.s.i. There should be no flow through the outlet before the DPI button has popped. This shows that the bypass valve has not failed open Page 202

61 (10) Increase pressure at the inlet until flow is obtained from the outlet. This shows that the bypass valve has opened, and should occur at a minimum pressure of 20 p.s.i. NOTE: Applied pressure should not exceed 100 p.s.i. (11) Release pressure and disconnect hand pump from filter inlet. (12) Re-connect filter unit inlet and outlet pipe connections. (13) Re-assemble filter unit as detailed in para 1.A. (8) to (16). 2. Cleaning/Painting A. Clean filter element. WARNING: STRONG CHEMICAL REAGENTS CAN CAUSE SERIOUS INJURY IF HANDLED IMPROPERLY, THEREFORE ONLY TRAINED PERSONNEL SHOULD PERFORM THIS OPERATION. (1) Recommended Procedure:- (a) Carefully remove the element-to-head seal. (b) Degrease element in either liquid or vapour trichlorethylene. (c) Immerse in boiling caustic soda solution (25% weight/volume) for 3 hours. (d) Remove and allow to drain. (e) Thoroughly wash in boiling water for a minimum of 5 minutes. (f) Immerse in cold nitric acid solution (15% volume/volume). (g) Remove and allow to drain. (h) Thoroughly wash in boiling water for a minimum of 5 minutes. (i) (j) (k) (l) Finally rinse in demineralised water. Oven dry at C for 15 minutes. Control of caustic soda and nitric acid solutions should be maintained by regular chemical analysis. Refit element-to-head seal or use new seal as necessary Page 203

62 SD3-60 AIRCRAFT MAINTENANCE MANUAL (2) Alternative Procedure:- If it is not convenient to carry out the recommended cleaning procedure, the following ad hoc method may be used. NOTE: This procedure may not clean the filter element to the 'as new' condition. (a) Carefully remove the element-to-head seal. (b) Immerse the element in an ultrasonic bath for 30 minutes. (c) Remove and allow to drain. (d) Refit element-to-head seal or use new seal as necessary. (e) Assembly element in a spare filter unit and flush out on a ground rig in a forward direction with clean filtered hydraulic oil at 4½ lmp. gallons per minute for 5 minutes. Ensure that the blockage indicator does not extend Page 204

63 AMM HYDRAULIC POWER, INDICATING - DESCRIPTION & OPERATION 1. General Three indicators on panel 7P display MAIN SYSTEM, LANDING GEAR EMERGENCY AND WHEEL BRAKE EMERGENCY pressures. NOTE: (1) Main system reading is a direct reading of oil pressure, whereas the emergency indications display nitrogen pressures in the related accumulators. (2) At a nominal pressure of approx psi for an ambient temperature of 20 C (68 F), the associated emergency accumulators will be fully discharged of oil. Indication of low pump delivery pressure is provided by warning lights on flight compartment 1P. Refer to , pb1. Reservoir contents are displayed by a direct reading gauge on the unit by an indicator on panel 7P. Refer to , pb Page 1

64 AMM PUMP LOW PRESSURE WARNING - DESCRIPTION/OPERATION 1. Description A pressure switch in the delivery line from each of the engine-driven pumps controls an associated low pressure warning light on the flight deck panel 1P. The switches, located on the wing centre-section front spar, are identified 1WP2 (left) and 2WP2 (right). 2. Operation On initial engine run up, the closed contacts of the associated pressure switch will break when approximately 2000 psi is exceeded - thus extinguishing the warning light. The light will remain extinguished unless the pressure subsequently falls to psi at which point the switch contacts will again change over to illuminate the light, thus providing warning of low pressure Page 1

65 SD3-60 AIRCRAFT MAINTENANCE MANUAL Low Pressure Warning Figure Page 2

66 AMM PUMP LOW PRESSURE WARNING - MAINTENANCE PRACTICES 1. Adjustment/Test A. Function check Special tools and equipment Hydraulic hand pump rig: T (1) Refer to , pb1. Open access panel 730JT and connect suction line of hand pump rig to GROUND TEST RETURN connector on hydraulic servicing panel in rear of left main landing gear fairing. (2) Obtain access to hydraulic pumps by removing access panel 410AL in engine cowling (left and right). (3) Disconnect MP line from left pump and connect rig pressure line to the system MP line. suitably cover pump connection. (4) Refer to , pb301. Energie the essential services busbar (left) and close circuit breaker No. 35 on left distribution panel 1D to illuminate low pressure warning light, HYD. L on panel 1P in flight compartment. NOTE: Step (5) which follows applies to aircraft Ser. Nos SH3651 and up and those prior Ser. Nos on which Serv. Bull. SD is incorporated. (5) Refer to , Figure 201 Disconnect restrictor pipeline in left stub wing as shown and plug system pipe connections. (6) Operate hand pump and raise pressure slowly, checking that warning light HYD. L is extinguished when pressure reaches 2000 ± 100 psi. (7) Reduce main system pressure by operating the wheel brakes, checking that warning light illuminates when pressure 'falls' to psi. (8) Remove cover from hydraulic pump connection and reconnect pump to MP line. (9) Repeat operations (4) to (8), reading right for left, HYD.R for HYD.L and circuit breaker No. 184 instead of circuit breaker No. 35. (10) If step (5) was applicable, refit restrictor pipeline removed in (5). (11) Disconnect hand pump rig from GROUND TEST RETURN connector. (12) Refit access panels 410AL and 730JT Page 201

67 Air Cargo Carriers, INC Report Number: Revision: A Aircraft Modification Pressure Switch Upgrade Part(s): Pressure Switch Aircraft: Shorts Brothers SD3-60, SD3-30 Prepared By: Luke Bartosuk Date: Checked By: Date: Approved By: Date:

68 Data Support Package Pressure Switch Modification Prepared By: Luke Bartosuk NOTICE OF REVISIONS REV. DESCRIPTION APPROVED DATE Initial Release LJB NHA: Report No.: Page 2 Aircraft: Shorts SD3-30 and SD3-60 Revision: A Date: 1/11/2010

69 Data Support Package Pressure Switch Modification Prepared By: Luke Bartosuk 1.0 Introduction The purpose of this project is to upgrade the pressure switch that controls the low hydraulic pressure warning light. The original pressure switch is an antiquated design that is prone to failure; the original unit fails regularly, due to internal leakage, condensation build up, and cold temperatures. This data package describes the replacement of the old pressure switch with a newer design used on many modern aircraft. Furthermore, the new switch has been specifically adapted by the manufacturer to operate at the same pressures as the original switch, and connect directly to both the original hydraulic line and electrical connector. In conclusion, the replacement pressure switch has been specifically built by Hydra-Electric to directly replace the original pressure switch. Original Pressure Switch New Pressure Switch NHA: Report No.: Page 3 Aircraft: Shorts SD3-30 and SD3-60 Revision: A Date: 1/11/2010

70 Data Support Package Pressure Switch Modification Prepared By: Luke Bartosuk Left: Original Pressure switch, mounted in aircraft. Right: new pressure switch mounted in aircraft. Disregard plate behind switch. 2.0 Removal Process The removal of the original pressure switch requires the following steps: 1. Remove pressure from system per AMM Disconnect electrical connector from switch. 3. Disconnect hydraulic line from switch. 4. Remove pressure switch by removing two bolts. 2.1 Installation Process The installation of the new pressure switch requires the following steps: 1. Connect the hydraulic line onto the switches pressure port. 2. Secure pressure switch in original location using the lower original switch mount bolt hole, using cushion clap part number MS21919WDG14 or MS21919WDG15 and AN3-3A bolt and AN washer. 3. Connect electrical connector, and safety wire to pressure switch. 4. Record modification in aircraft log book. 5. Perform operational check of system by running aircraft engines, ground hydraulic power will not check system. 6. Check for leaks 7. Restore system pressure per AMM Install new switch in accordance with AC B, maintenance manual does not contain step by step removal and installation procedures, complete pressure switch maintenance practices are included in appendix A. 3.0 Required Parts (PER SIDE) 1. Hydra Electric pressure switch part # 15h0166PH 2. Bolt part number AN3-3A NHA: Report No.: Page 4 Aircraft: Shorts SD3-30 and SD3-60 Revision: A Date: 1/11/2010