SD3-60 AIRCRAFT MAINTENANCE MANUAL 76.pdf · SD3-60 AIRCRAFT MAINTENANCE MANUAL ... POWER CONTROL -...

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Jun 30/01 76-10-00 Page 1 EFFECTIVITY: All z SD3-60 AIRCRAFT MAINTENANCE MANUAL AMM 76-10-00 POWER CONTROL - DESCRIPTION & OPERATION 1. General The control of each engine is afforded by three levers (POWER, FUEL and PROP) mounted on the flight compartment centre console. Lever operation and details of their console-to-engine linkages are respectively given in paras 3, 4 and 5. The engines main controlling agents are the fuel control unit (F.C.U) which comprises scheduling and fuel metering sections and the propeller governor which embodies a propeller fuel governor and a beta valve. The engine has two defined modes of operation, these are:- A. PROPELLER GOVERNING (power control lever set in the ’air’ regime i.e. between FLIGHT IDLE and take-off). NOTE: In this mode, propeller RPM will be maintained, when possible, at that selected by the PROP lever by automatic changes in blade pitch brought about by the propeller governor. B. BETA GOVERNING (power lever set in the ’ground’ regime i.e. in the range below FLIGHT IDLE to full REVERSE). NOTE: In this mode propeller blade angle is directly scheduled by the power lever. The FUEL lever is employed to (a) cut-off metered fuel and (b) choose the gas generator minimum governing speed. Two positions are available for the latter; (i) GROUND and (ii) FLIGHT. 2. Gas generator speed scheduling To assist comprehension of the power lever function (para 3.), some limited discussion of the F.C.U. input control and response aspects is necessary. The essential elements of the F.C.U. in this respect, i.e. the 3D cam, tachometer, fuel valve and P3 sensor are schematically presented. Refer to Figure 1. In steady state operation the 3D cam and fuel valve are rotatively and axially stable in positions appropriate to set speed i.e. metered fuel flow P2, compressor discharge pressure P3 and the tachometer are in balanced compatibility. Consider:- A. Acceleration schedule The power lever will rotate the 3D cam to permit the cam follower to shorten radial contact with respect to the cam axis; this allows the fuel valve to rotate under spring-action to further laterally open the metering port.

Transcript of SD3-60 AIRCRAFT MAINTENANCE MANUAL 76.pdf · SD3-60 AIRCRAFT MAINTENANCE MANUAL ... POWER CONTROL -...

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AMM76-10-00 1.0.0.0POWER CONTROL - DESCRIPTION & OPERATION

1. General

The control of each engine is afforded by three levers (POWER, FUEL and PROP) mounted on the flight compartment centre console. Lever operation and details of their console-to-engine linkages are respectively given in paras 3, 4 and 5.

The engines main controlling agents are the fuel control unit (F.C.U) which comprises scheduling and fuel metering sections and the propeller governor which embodies a propeller fuel governor and a beta valve.

The engine has two defined modes of operation, these are:-

A. PROPELLER GOVERNING (power control lever set in the 'air' regime i.e. between FLIGHT IDLE and take-off).

NOTE: In this mode, propeller RPM will be maintained, when possible, at that selected by the PROP lever by automatic changes in blade pitch brought about by the propeller governor.

B. BETA GOVERNING (power lever set in the 'ground' regime i.e. in the range below FLIGHT IDLE to full REVERSE).

NOTE: In this mode propeller blade angle is directly scheduled by the power lever.

The FUEL lever is employed to (a) cut-off metered fuel and (b) choose the gas generator minimum governing speed. Two positions are available for the latter; (i) GROUND and (ii) FLIGHT.

2. Gas generator speed scheduling

To assist comprehension of the power lever function (para 3.), some limited discussion of the F.C.U. input control and response aspects is necessary. The essential elements of the F.C.U. in this respect, i.e. the 3D cam, tachometer, fuel valve and P3 sensor are schematically presented. Refer to Figure 1.

In steady state operation the 3D cam and fuel valve are rotatively and axially stable in positions appropriate to set speed i.e. metered fuel flow P2, compressor discharge pressure P3 and the tachometer are in balanced compatibility.

Consider:-

A. Acceleration schedule

The power lever will rotate the 3D cam to permit the cam follower to shorten radial contact with respect to the cam axis; this allows the fuel valve to rotate under spring-action to further laterally open the metering port.

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Resultant signalling rise in Ng will cause:-

(1) The tachometer flyweights to increase spring-reaction under the cam.

(2) Rising pressure in the P3 (compressor discharge) sensor to unbalance the fuel valves axial positioning loads, permitting 'self-propagating' axial opening of the metering port to a point where:-

(3) The effect of P1 increase on the differential areas of the 3D cams upper and lower chambers will have advanced the cam axially towards the tachometer sufficiently to cause the follower to move radially outwards to 'back-off' rotative (signalling) metering by an amount equal to the P3 continuing demand.

The gas generator will then have resumed steady state operation at the higher selected speed.

B. Deceleration schedule

The power lever will rotatively re-position the 3D cam such that the follower moves radially outwards from the cam axis; this rotates the fuel valve to reduce lateral opening of the metering port. Resultant signalling decrease in Ng and consequent reductions in respective compressor and fuel pump discharge pressures P3 and P1 will cause:-

(1) The P3 sensor to unbalance the fuel valves axial positioning loads such that axial opening of the metering port progressively reduces to a point where:-

(2) The effect of P1 decrease on the 3D cams upper and lower chambers will have allowed the cam to lift sufficiently under tachometer spring action to cause the follower contact to move radially towards the cam axis to increase fuel valve rotative metering by an amount equal to the P3 'fall off' demand.

The gas generator will then have resumed steady state operation at the lower selected speed.

3. Power lever

A. Function

The pilots power lever sets the gas generator speed point and when in the 'ground' regime (BETA MODE) will reset the propeller fuel governor to permit direct selection of propeller blade angle.

In the PROP GOVERNING MODE the power lever schedules the gas generator speed (Ng) set point by positioning the F.C.U. control arm through the medium of a cambox arrangement mounted on the accessory gearbox flange. Refer to Figure 2.

This appropriately rotates the 3D cam within the F.C.U. to initiate the required Ng change (re-scheduling events to the newly-selected on-speed condition are detailed in para 2).

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Fuel Control Unit - Scheduling AspectsFigure 1

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In the BETA GOVERNING MODE the Ng speed setting function is similar except when propeller R.P.M. nears propeller governor set speed. When this occurs the propeller fuel (Nf) governor, which is mechanically re-set when the power lever is selected below FLIGHT IDLE will open an orifice in the Nf governor to bleed air from the F.C.U. P3 sensor to reduce fuel flow and thus propeller speed.

NOTE: Beta control is only possible when the propeller underspeeds relative to its set speed. This positions the fly-weight operated pilot valve within the propeller governor to permit oil flow to and from the propeller hub at the behest of the beta valve.

The beta valve is controlled by a reversing lever which pivots about the front of the valve. The outer arm of the lever is connected to a cased wire-rope which attaches to the power lever input cambox. The inner arm connects to a carbon slipper block which rides in a feedback collar on the propeller assembly. Movement of the power lever in the ground regime i.e. in the range below FLIGHT IDLE, will initially cause the wire rope to position the beta valve to direct pressurised oil to or from the propeller hub dependent upon direction of power lever movement.

NOTE: Rearward movement of the power lever will in consequence move the beta valve rearward to admit oil from the governor pump to the propeller hub and thus fine-off blade angle towards reverse pitch. Forward movement will move the beta valve forward to vent oil from the propeller the blades of which will coarsen towards feather.

Simultaneous to blade pitch change, the feedback collar will move and pivot the reversing lever about its wire-rope pick up to attempt to place the beta valve in its pre-selected null position. Provided the pivot point is static i.e. power lever movement ceased - the attempt will be successful and the blades will be hydraulically locked at the requested pitch.

B. Lever-to-engine linkage

Refer to Figure 3.

The control system to each engine consists of a conventional cable circuit within the fuselage which is connected to the engine by means of a Bowdenflex flexible push-pull system within the wing.

NOTE: The flexible system is essentially a cased linear ball race.

Each cable circuit is substantially routed through the fuselage roof structure. It is connected between an input capstan in the flight deck centre console and the lower quadrant of the appropriate power/RPM pulley group on the centre-wing front spar.

The flexible push/pull system attaches to an output lever which is fixed to the quadrant. The system is routed outboard through the centre wing leading edge to rib station 106.5 and thence to the input arm on the control cambox (mounted on the engines accessory gearbox flange).

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Engine power input cambox and prop reserving systemFigure 2

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The input capstans in the centre console are linked by control rods to the pilots power levers. Refer to Figure 4.

The power control levers are mounted in line, flanking a camplate assembly which is common to both. The camplate, mounted on the levers axis bolt is fixed at the forward end to the console top plate. The forward end of the camplate assembly is V-sectioned and is fitted with four stop bolts, two for 'take-off' and two for 'reverse'. The cam consists of matching stepped slots in the assembly side plates which are concentric with the levers axis. The slots each accept a follower pin mounted on the associated power lever.

The power levers are each enclosed in an inverted 'T' shaped mounting shoe, the shoes being mounted on the axis bolt previously mentioned. The bottom of each power lever is slotted, allowing the levers to be moved both away from and towards the levers axis, thus allowing the follower pins to be lifted or dropped as required to suit the position desired in the camplate. A spring and guide pin assembly is fitted between each shoe and lever to bias the lever to its lowest position in the shoe, thus ensuring that definite pilot action is required to lift the levers radially outwards from their axis to bring the cam follower pins back into the lower power ranges. Each lever shoe is fitted with an adjustable friction device to provide 'feel' and maintain lever position.

To obviate inadvertent selection of the power levers below FLIGHT IDLE while in flight, a ground/air lever (para C) is provided.

NOTE: The power levers camplate assembly also incorporates a 'built-in' baulk lever which, when the flying controls are ground-selected locked, restricts the forward movement of the power levers in the air regime to positions relative to 50% power. The baulk mechanism is described in para D.

C. Ground/air lever

Refer to Figure 5.

The ground/air lever is situated immediately forward and laterally between the two power levers. The primary function of the lever is to prevent unintentional operation of the power levers to positions below FLIGHT IDLE.

NOTE: A secondary low blade angle (L.B.A.) back-up stop system on each engine hydraulically prevents fining off of the propeller blades beyond flight idle when the power levers are in the air regime. Refer to 61-21-00, pb1. The back-up stop is removed when microswitches are operated by selection of the ground/air lever to ground.

The lever assembly basically consists of a cranked lever to which is attached a trip fork for the L.B.A. microswitch and a spring-loaded baulk spool. The lever is biased to the air (baulk) position by a torsion spring which is fitted at the lever hinge axis.

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Power Lever Control CircuitsFigure 3

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Power Levers in ConsoleFigure 4

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Ground/Air Lever - OperationFigure 5

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The baulk spool is mounted on a guide/retaining pin which attaches to the bottom of the lever. When the lever is in the air position, movement of either or both power levers towards FLIGHT IDLE will drive the spool up the pin under the action of the power lever toe/toes. Shimming is introduced between the spool and the lever to arrest the spool when the power lever/levers reach FLIGHT IDLE.

When ground is selected by pressing the lever to the down position - the baulk spool is moved clear of the top of the power lever toes and is 'shot' to the bottom of the pin by its spring. The curved front of the power lever toes can then ride on the circumferentially contoured wall of the baulk spool into the ground regime (FLIGHT IDLE to full REVERSE).

Providing that the 'max-taxi' baulk (para. D) is withdrawn - the power levers can be moved to take-off from any position below FLIGHT IDLE without impediment by the ground/air lever.

NOTE: The design length of the baulk spool guide/retaining pin is such that the lever will not automatically reset to the baulk position on moving the power levers from the ground to the air regime until immediately after 'max-taxi' power is reached (see detail C); this allows for taxiing of the aircraft with the max-taxi baulk effective without recourse to repeated selection of the ground/air lever to ground.

D. 'Max-taxi' baulk

Refer to Figure 6.

To facilitate taxiing operations, a 'max taxi' baulk mechanism is incorporated to restrict engine power and thus ground speed, when the flying controls are locked.

The mechanism consists of a baulk lever, housed within the power levers camplate assembly, which is connected by a flexible operating cable to the flying controls lock lever shaft.

When the controls lock lever is selected LOCKED - the cable will position the baulk lever within the camplate to prevent forward movement of the power levers in the air regime beyond positions relative to 50% power.

Selection of the controls lock lever to UNLOCKED will move the baulk lever clear of the camplate air regime slot, thus permitting unimpeded advancement of the power levers to maximum power positions.

A compression spring assembly, mounted between the baulk lever and the camplate is incorporated to:-

(1) Ensure that the baulk lever will remain clear of the camplate slot should a cable connection failure occur during flight.

(2) Relieve compression loads on the operating cable when the controls lock lever is selected from the LOCKED to the UNLOCKED position.

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Max - taxi Baulk MechanismFigure 6

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E. Reverse thrust Baulk Lever Mechanism

The mechanism is located immediately aft of the power levers (see Figure Refer to Figure 4). The baulk lever, which prevents unintentional power lever selection to positions below GROUND FINE, requires lifting by its 'finger-tab' projections to permit such action. Automatic reset to the baulk position will occur under the action of a torsion spring when the power lever/s are returned to positions at or beyond GROUND FINE.

4. Fuel lever

A. Function

The pilots three-position FUEL lever is employed to set the gas generator minimum governing speeds and to provide a means of shutting off metered fuel flow.

Refer to Figure 7. When the control lever is selected OFF (rearmost position) the idle reset/cut-off lever on the engines F.C.U. will move to contact a cut-off stop and in so doing will depress a pump unloading valve plunger. Metered fuel is then bypassed internally in the F.C.U. and no fuel is delivered to the nozzles.

When the control lever is set to GROUND or FLIGHT, consequent positioning of the F.C.U. idle select arm will limit power reduction rotation of the internal 3D cam such that rotational closing of the fuel valve metering port beyond that appropriate to the selected idling speed is prevented.

Respective GROUND and FLIGHT settings will provide corresponding low and high idle speeds of 71% and 79%.

B. Lever-to-engine linkage

Refer to Figure 7.

The control system to each engine is similar, each basically consisting of a conventional cable circuit within the fuselage which joins with a cased wire push/pull system in the wing.

Each cable circuit is substantially routed through the fuselage roof structure. It is connected between an input capstan in the flight compartment centre console and the appropriate fuel condition quadrant on the centre-wing front spar.

The cased wire push/pull system attaches to an output lever which is fixed to the quadrant. The system is routed outboard through the centre-wing leading edge to rib station 106.5 and thence to the idle reset/cut-off lever on the engines fuel control unit.

The input capstans in the centre console are linked by control rods to the pilots fuel control levers as shown on Fig. Refer to Figure 8.

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Fuel Condition Control CircuitsFigure 7

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The control levers are mounted on the right side of the centre console top plate. They are mounted on the axis bolt which also provides common attachment for the power and propeller speed levers. The stop bracket mounted immediately forward of the levers is provided with eight adjustable stop bolts, four of which are employed to set the fuel control levers limits of travel; two to arrest the levers at the extreme forward (FLIGHT) position and two to arrest the levers at the fully aft (OFF) position.

NOTE: The remaining four stop bolts are used in conjunction with the propeller speed levers (para 4).

Unintentional operation of the levers to the OFF position is prevented by interference pieces which are rivetted to the idented lever cover. These act as stop gates at the GROUND position around which the levers must be laterally sprung to allow full rearward movement to the OFF position.

The levers share an adjustable friction device which when tightened by a control knob will maintain the levers at their selected positions.

5. Propeller lever

A. Function

The pilots PROP lever is employed to select the propeller governor speed set point and also provide a means of feathering the propeller.

When selected fully aft (through a detent) to the FEATHER position - the range skirt located below the governors speed set lever will have fully depressed a plunger to operate the governors integral feathering valve; servo pressure oil in the propeller hub will then dump to sump, causing the blades to feather under the action of springs and counter-weights.

NOTE: The propeller may be feathered with the gas generator section of the engine operating.

WARNING: (A) POWER LEVER MUST NOT BE BELOW FLIGHT IDLE WHEN FEATHERING THE PROPELLER (OVER-TEMPERATURING OF THE ENGINE WILL OCCUR IF FEATHER IS SELECTED WHILST POWER LEVER IS IN BETA RANGE).

(B) RESTRICT IDLING TIME IN FEATHER TO AVOID EXCEEDING OIL TEMPERATURE MAX. LIMIT (110°C).

Selection of the pilots PROP lever between the minimum speed set position (immediately forward of the FEATHER detent) to the maximum (most forward) position will cause the lever on the propeller governor to progressively increase the load on the governors internal speeder spring.

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Fuel Condition Levers in ConsoleFigure 8

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When the engine is operating in the Propeller Governing Mode i.e. associated POWER lever set in the range between FLIGHT IDLE and `take-off', the speeder spring, in conjunction with governor flyweights (driven by the propeller reduction gearbox) will monitor the position of the governor pilot valve to control the flow of oil to and from the propeller as detailed in Notes (1) to (3) which follow. The resultant automatic changes in blade pitch will maintain the propeller at selected speeds of between 1150 to the normal governed maximum of 1675 +25 -0 PRPM.

NOTE: (1) Should the propeller be operating ON-SPEED i.e. running at selected speed - the governors flyweight will compress the speeder spring to position the pilot valve in an essentially null position. The propeller blade angle will then be that which balanced against power will maintain set speed.

(2) Should propeller UNDERSPEED take place e.g. POWER lever moved to a lower power setting the consequent reduction in flyweight centrifugal force will cause the speeder spring to depress the pilot valve and open a flow path from the governor pump to the propeller The resultant oil flow to the propeller will cause the blade angle to fine off and the propeller speed and thus flyweight speed will increase to again bring the pilot valve to the null-position. The propeller will then be operating at set speed.

(3) Should propeller OVERSPEED occur e.g. POWER lever moved to a higher power setting - the consequent increase in flyweight centrifugal force will lift the pilot valve against the speeder spring and open a flow path from the propeller to sump. The resultant oil flow from the propeller causes the blade angle to coarsen and the propeller speed and thus flyweight speed will reduce to bring the pilot valve to the null position (propeller operating at set speed).

Propeller overspeed limiting throughout the range of speed settings (engine operating in the Propeller Governing Mode) is afforded by the propeller fuel (Nf) governor which is an integral part of the propeller governor. The Nf governor will take effect at respective overspeed conditions of between 6% and 10% above maximum and minimum settings to reduce power turbine and thus propeller speed.

The Nf governor basically consists of a yoked bell-crank which pivots about a reset post is operated by the propeller governor flyweight head during overspeed. When the overspeed limit for the set speed is reached the bell-crank will open a governing orifice which is pipe-connected to the P3 sensor in the engines F.C.U. Opening of the orifice will cause the sensor to signal the F.C.U. fuel valve to reduce metered flow; gas generator and thus power turbine speed will then reduce to assist the propeller to return to the selected speed.

NOTE: Additional overspeed protection is afforded by a separate overspeed governor as detailed in 61-23-00.

When the engine is operating in the Beta Governing Mode ie. associated POWER lever moved aft of FLIGHT IDLE - the Nf governor reset post is repositioned by an interconnecting rod from the power lever-controlled reversing linkage to cause propeller fuel governing to control gas generator speed to that which will maintain propeller speed at approximately 4% below maximum set speed (1675 RPM) and 10% below minimum set speed (1150 RPM).

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This will cause the propeller governors fly-weight-controlled pilot valve to be so positioned as to permit direct selection of blade angle by the beta valve and reversing linkage in response to power lever movement as detailed in para 3.A.

B. Circuit

Refer to Figure 9.

The control system to each engine is similar, each basically consisting of a conventional cable circuit within the fuselage which joins with a cased wire push/pull system in the wing.

Each cable circuit is substantially routed through the fuselage roof structure. It is connected between an input capstan in the flight deck centre console and the upper quadrant of the appropriate power/R.P.M. pulley group on the centre wing front spar.

The cased wire push/pull system attaches to an output lever which is fixed to the quadrant. The system is routed outboard through the centre-wing leading edge to rib station 106.5 and thence to the propeller governor speed select lever on the engine.

The input capstans in the centre console are linked by control rods to the pilots propeller speed levers. Refer to Figure 10.

The propeller levers are mounted centrally on the centre console top plate. They are fitted between the power and fuel control levers - all of which share a common axis bolt. Stop brackets mounted immediately forward and aft of the levers incorporate eight adjustable stop bolts, four of which are employed to set the propeller lever limits of travel; two to arrest the levers at the extreme forward (max) position and two to arrest the levers at the extreme forward (max) position and two to arrest the levers at the fully aft (FEATHER) position.

NOTE: The remaining four stop bolts are used in conjunction with the fuel control levers (para.Refer to 3.).

Unintentional entry of the levers into the FEATHER position is prevented by spring detent linkages which connect to the input capstans. Refer to Figure 10.

The linkages are each comprised of a rod on which a detented spring clip is mounted. The clip will offer resistance to control lever rearward movement beyond min. R.P.M. setting when the detent bears on a tube mounted laterally across the front of the console. It then requires increased loading on the control lever to force the detent to 'hop' the tube and thus permit full rearward movement of the control lever to FEATHER.

The control levers share an adjustable friction device which when tightened by a control knob will maintain the levers at their selected positions.

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Propeller R.P.M. Control CircuitsFigure 9

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Propeller R.P.M. Controls in ConsoleFigure 10

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AMM76-10-00 2.0.0.0POWER CONTROL - ADJUSTMENT/TESTDUPLICATE INSPECTION

WHENEVER ANY PART OF THE SYSTEM IS DISMANTLED, ADJUSTED, REPAIRED OR RENEWED, DETAILED INVESTIGATION MUST BE MADE ON COMPLETION TO ENSURE THAT DISTORTION, TOOLS, RAG OR ANY LOOSE ARTICLES OR FOREIGN MATTER SUCH AS COULD IMPEDE THE FREE MOVEMENT AND SAFE OPERATION OF THE SYSTEM ARE NOT PRESENT, AND THAT THE SYSTEMS AND INSTALLATIONS IN THE WORK AREA ARE CLEAN.

THAT PART OF THE SYSTEM DISTURBED AS A RESULT OF MAINTENANCE PRACTICES PERFORMED SHALL BE SUBJECTED TO A DUPLICATE INSPECTION FOR SECURITY OF LOCKING DEVICES, FULL AND FREE MOVEMENT AND DIRECTIONAL SENSING CHECKS AND, FOR AIRCRAFT ON THE BRITISH REGISTER, THE COMPLETION OF THIS WORK SHALL BE CERTIFIED IN ACCORDANCE WITH BRITISH CIVIL AIRWORTHINESS REQUIREMENTS, SECTION A, CHAPTER A5-3.

1. Rigging of controls

The POWER, FUEL and PROP levers on the flight compartment centre console, together with their related control systems are respectively rigged as detailed in para. A, B and C.

NOTE: At completion of airframe rigging, run the engine and perform the engine rigging checks, making any necessary adjustments. Refer to 71-00-00, pb1.

Special tools and equipment:-

- Tensiometer: T360.20.01

Rigging pins:-

- M-3: T360.27.46- M-5: T360.27.48- M-6-P: T360.76.01- M-6-S: T360.76.02- M-7-P: T360.76.03- M-7-S: T360.76.04

A. Rig power control system

Refer to Figure 501.

(1) Disconnect clevis end at rear of cased wire rope where attached to propeller control cam (detail C).

(2) With reference to detail A, disconnect control rod SD3-47-0699 and insert rigging pin M-3.

(3) Insert appropriate rigging pin, M-6-P - left, M-6-S - right, (see detail B).

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(4) Arrange cables as shown in main view.

(5) Equally adjust turnbuckles to provide cable tensioning appropriate to ambient temperature. Refer to 20-09-01, pb1.

(6) Check that rigging pins can be removed and inserted freely. Refit pins.

(7) Fit locking clips to turnbuckles. Refer to 20-09-02, pb1.

(8) Place power lever (detail A) in FLIGHT IDLE position, adjust control rod SD3-47-0699 to suit, tighten locknuts, bend up lock washers and reconnect.

(9) With reference to detail C, adjust clevis end of flexible push-pull system to power input lever such that follower lever adopts the 'flight idle' position shown. Tighten locknut and wirelock.

(10) Remove rigging pins.

(11) 'Back off' the adjustable stops at the power lever (detail A).

(12) Move the power lever forward and arrest and hold when the follower lever on the engine (detail C) adopts the 'max. power' position. Set the adjustable stop to contact the power lever at the maintained position and tighten the locknut.

(13) Press ground/air lever down and move the power lever aft, lifting through the cam gates and arrest and hold when the follower lever on the engine adopts the 'reverse' position. Set the adjustable stop to contact the power lever toe and tighten the lockt.

(14) Return power lever to FLIGHT IDLE and reconnect the cased wire rope to the third hole from the top in the propeller control cam as shown (detail C).

B. Rig fuel condition control system

Refer to Figure 502.

(1) With reference to detail A, perform the following:-

(a) Disconnect control rod SD3-47-0701 and insert rigging pin M-5.

(b) Adjust rear stop to set control lever in 'cut-off' position; tighten locknut.

(c) Maintain lever position, adjust the control rod to suit, tighten locknuts, bend up tab washers and reconnect.

(2) Disconnect sleeved input cable from the idle reset/cut-off lever (detail C).

(3) Insert appropriate rigging pin, M-7-P - left, M-7-S - right (see detail B).

(4) Arrange cables as shown in main view.

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Power Lever Controls - RiggingFigure 501

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(5) Equally adjust turnbuckles to provide cable tensioning appropriate to ambient temperature. Refer to 20-09-01, pb1.

(6) Check that rigging pins can be removed and inserted freely. Refit pins.

(7) Fit locking clips to turnbuckles as detailed in 20-09-02.

(8) Hold idle reset/cut-off lever (detail C) against cut-off stop. Adjust sleeved input cable to suit and reconnect to third hole from the top in the lever.

(9) Remove rigging pins.

(10) Screw in the forward stop (detail A) and move the FUEL lever forward until the engine lever bears on the flight stop (detail C). Maintain this condition and adjust stop at console to contact FUEL lever.

C. Rig propeller R.P.M. control system

Refer to Figure 503.

(1) With reference to detail A, perform the following:-

(a) Disconnect control rod SD3-47-0700 and insert rigging pin M-3.

(b) Disconnect spring detent linkage from control pulley.

(c) Adjust forward stop to set control lever in 'max R.P.M.' position. Tighten locknut.

(d) Maintain lever position, adjust the control rod to suit, tighten locknuts, bend up tab washers and reconnect.

(2) With reference to detail C, perform (a) - right engine or (b) - left engine:-

(a) Disconnect sleeved input cable where attached to the speed select lever on the propeller governor.

(b) Disconnect propeller synchronizer rod end trimmer where attached to speed select lever.

(3) Insert appropriate rigging pin, M-6-P - left, M-6-S - right (see detail B).

(4) Arrange cables as shown in main view.

(5) Equally adjust turnbuckles to provide cable tensioning appropriate to ambient temperature. Refer to 20-09-01, pb1.

(6) Check that rigging pins can be removed and inserted freely. Refit pins.

(7) Fit locking clips to turnbuckles. Refer to 20-09-02, pb1.

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Fuel Condition Controls - RiggingFigure 502

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(8) With reference to detail C, perform (a) - right engine or (b) - left engine:-

(a) Hold engine lever against 'max RPM' stop, adjust sleeved input cable to suit and reconnect.

(b) Rig the propeller synchronizer rod end trimmer. Referto 61-24-00, pb201.

(9) Remove rigging pins.

(10) Screw in the rear stop (detail A) and move the control lever aft until range skirt below the speed select lever on the governor fully depresses the feathering valve plunger. Maintain this condition and adjust stop at console to contact PROP lever.

(11) Reconnect the spring detent linkage to the control pulley (detail A).

D. Rig the Minimum PRPM Spring Detents

Refer to 76-10-00, Figure 10.

Perform the following, should a spring detent be replaced or the setting disturbed;

(1) At the forward end of the centre console, back off associated spring detent adjustment nuts to allow free movement during subsequent engine run.

(2) Operate associated engine with the following settings:-

(3) Move associated PROP lever back slowly until 1150 ± 20 p.r.p.m. is obtained and pencil mark lever position on console cover.

(4) Shut down engine. Refer to 71-00-00, pb1.

(5) Reselect PROP lever to the position marked by operation (3) and friction lock.

(6) Adjust spring detent positioning locknuts until detent is bearing against the guide tube assembly as shown in detail B.

(7) Wirelock adjustment nuts.

(8) Release friction lock.

POWER lever Flight IdlePROP lever Fully forwardFUEL lever Flight

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Propeller R.P.M. Controls - RiggingFigure 503

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AMM76-10-00 3.0.0.0POWER CONTROL - INSPECTION/CHECK

1. Check Rigging

A. Check power control system

Refer to 76-10-00, Figure 501.

(1) Place power control lever (pilots console) in FLIGHT IDLE position (detail A).

(2) Insert rigging pins M-3, M-6-P (left) and M-6-S (right) as indicated (details A and B).

(3) Check that rigging pins can be removed and inserted freely without disturbing the position of the power lever.

(4) Check that cable tension is appropriate to ambient temperature. Refer to 20-09-01, pb1.

(5) Remove rigging pins M-3, M-6-P (left) and M-6-S (right).

B. Check fuel condition control system

Refer to 76-10-00, Figure 502.

(1) Place fuel condition control lever (pilots console) in the aft 'cut-off' position (detail A)

(2) Insert rigging pins M-5, M-7-P (left) and M-7-S (right) as indicated (details A and B).

(3) Check that rigging pins can be removed and inserted freely without disturbing the position of the fuel condition control lever.

(4) Check that cable tension is appropriate to ambient temperature. Refer to 20-09-01, pb1.

(5) Remove rigging pins M-5, M-7-P (left) and M-7-S (right).

C. Check propeller RPM. control system

Refer to 76-10-00, Figure 503.

(1) Place propeller RPM. control lever (pilots console) in the forward 'max. RPM' position (detail A).

(2) Insert rigging pins M-3, M-6-P (left) and M-6-S (right) as indicated (details A and B).

(3) Check that rigging pins can be removed and inserted freely without disturbing the position of the propeller RPM. control lever.

(4) Check that cable tension is appropriate to ambient temperature. Refer to 20-09-01, pb1.

(5) Remove rigging pins M-3, M-6-P (left) and M-6-S (right).

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AMM76-10-01 1.0.0.0GROUND/AIR LEVER - MAINTENANCE PRACTICES

1. Adjustment/Test

A. Function check

Special tools and equipment:-

- Rigging pin M-3: . . . . . . . . . . . . . . . . . . . . T360.27.46

(1) Place POWER levers at FLIGHT IDLE

(2) Refer to 76-10-00, Figure 501. Insert rigging pin M-3 where shown.

(3) Remove circular access panel in left sidewall of centre console, adjacent to POWER levers.

(4) Disconnect power input control rods where attached to POWER levers. Retain attachments except split pins.

(5) Set the flying controls locking handle on the centre console to the UNLOCKED position.

(6) Move both POWER levers fully forward and check as follows:-

(a) that the ground/air lever is in its raised 'air' position.

(b) that there is no excessive lateral play or looseness in each POWER lever, indicating wear in bushes and/or mounting shaft.

(7) Retard levers to FLIGHT IDLE and attempt to enter ground range.

NOTE: The ground/air lever baulk spool should prevent this.

(8) Press down on ground/air lever and check that POWER lever/s can now enter ground range (baulk removed).

(9) Return POWER levers to FLIGHT IDLE and select flying controls locking handle to LOCKED position.

(10) Move both POWER levers forward until arrested by the ‘max-taxi’ baulk mechanism (effective when flying controls are selected LOCKED).

(11) Check that ground/air lever has remained at the lower ‘ground’ position.

(12) Select controls UNLOCKED and check that further slight forward movement of both POWER levers causes the ground/air lever to reset to the raised ‘air’ position.

(13) Return POWER levers to FLIGHT IDLE and reconnect control rods.

(14) Remove rigging pin.

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(15) Refit access panel to centre console left sidewall.

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AMM76-10-06 5.0.0.0CARBON SLIPPER BLOCKS (BETA PITCH CONTROL) - MAINTENANCE PRACTICES

1. Inspection/Check

A. Check slipper block wear.

Refer to 61-21-06, pb201.

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AMM76-10-11 6.0.0.0CABLE (ENGINE POWER) PT.NO.A55 2318 (LH) / 2326 (RH) - MAINTENANCE PRACTICES

1. Removal/Installation

A. Remove a control cable

Refer to Figure 201.

(1) Place power control levers (pilots console) in FLIGHT IDLE position.

(2) Gain access to power control cable run by removing associated access panels as follows. Refer to 6-30-00, pb1.

(3) Insert rigging pin M-6-P (left) or M-6-S (right) as appropriate in lower pulley quadrant (centre wing).

(4) At cable run through engine compartment:-

(a) Remove and retain cable securing clips (six-left installation, or seven-right installation) along with four bolts, washers and nuts, noting positions for subsequent installation.

(b) Disconnect clevis end from control cambox input arm, retaining nut, washer and bolt.

(c) Disconnect swivel abutment from slotted mounting bracket, retaining two nuts, washers and bolts.

(d) Support and withdraw cable from the mounting bracket, and remove from engine compartment, noting cable route for subsequent installation.

(5) At cable run through wing:-

(a) Remove and retain seal and sealing plate, along with two nuts, washers and bolts at Wing Stn. 106.5.

(b) Remove and retain cable housing ferrules at wing Stns. 83.5 and 68.8, along with four nuts, washers and bolts.

240 PL or 240 MR (left or right)510 DT or 610 CT (left or right)510 FT or 610 FT (left or right)410 BT410 AT410 AR420 BB

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Power Control Cable - Removal/InstallationFigure 201

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(c) Disconnect eye end from lower quadrant output lever, retaining nut, three washers and bolt, noting position of washers for subsequent installation.

(d) Remove eye end and stiffnut from cable.

(e) Break locking wire, and remove split pin, gland nut and jam nut.

(f) Disconnect mounting bracket from structure at wing Stn. 45, retaining two bolts and washers.

(g) Remove mounting bracket with attached swivel abutment from cable. Retain mounting bracket along with two slotted nuts, washers and bolts for attachment of replacement swivel abutment.

(h) Withdraw cable to expose remaining jam nut.

(i) Break locking wire, and remove jam nut from cable.

(6) Withdraw cable from wing at Stn. 106.5.

B. Preparation for cable installation.

NOTE: The cable to be installed should be received in a 'lazy 8' configuration - not circular form.

(1) Hold the cable in the upright position just below cross over section, and remove ties.

(2) At nearest end, proceed to uncoil cable, each loop individually, without force or twisting.

(3) With the cable laid out straight, remove and retain all attachments from both ends.

(4) Roll one end of the cable until the 'I' ident on the end rod assumes a horizontal position.

(5) Maintaining this position, create a 'hump' with the hand underneath the cable, and transfer along complete length.

NOTE: The 'I' ident on the opposite end rod flat should also assume a horizontal position, indicating that the cable is not twisted.

(6) Manually operate the control checking for free movement. The linear rolling friction should not exceed 16 oz.

NOTE: If the load is high, becomes erratic, or increases during movement - the control cable should not be installed. Procedures (1) to (6) should be repeated on a replacement cable.

(7) Install the cable as detailed in para C.

C. Install a control cable

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Refer to Figure 201.

NOTE: The load carrying rails in the cable should be checked during installation to ensure proper orientation. This is achieved by maintaining the 'I' and 'O' idents on the end rod flats in the proper attitude.

(1) With the 'I' idents uppermost, bend one end of the cable through 180° (see Detail 1).

CAUTION: MINIMUM BEND RADIUS TO BE 3 INCHES.

(2) Maintaining cable attitude, insert straight section through housing at Wing Stn. 106.5, feeding through to lower pulley quadrant output lever (centre wing).

(3) Further bend cable down through 90° (see Detail 2), and route the 180° loop into right side of associated engine compartment (as noted during removal), withdrawing cable from wing as necessary until loop is below engine.

(4) Helex the 180° loop forward through 90° (see Detail 3), re-inserting cable back into engine compartment and wing.

NOTE: The 'I' ident on the end rod flat should be facing aft.

(5) Before fitment of cable attachments, manually operate control checking for no appreciable load increase.

(6) Fit attachments to control cable at engine as follows:-

Jam nut, swivel abutment, second jam nut, gland nut, rubber gaiter, stiffnut (reverse fit) and clevis end.

NOTE: When attaching stiffnut, and clevis end, ensure that control remains orientated by use of the spanner flats.

(7) Position swivel abutment onto top of slotted bracket and attach with two bolts, washers and nuts retained on removal.

(8) Temporarily attach clevis end to control cambox input arm, with bolt, washer and slotted nut.

(9) Adjust control cable outer casing to suit cable travel, by use of the jam nuts.

(10) Maintain the setting as follows:-

(a) Position upper jam nut against swivel abutment bearing.

(b) Ensure gland nut wire locking hole is aligned with groove in cable outer casing. Fit split pin.

(c) Wire lock between jam nut and gland nut split pin in a figure eight configuration.

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(d) Position lower jam nut against swivel abutment bearing.

(e) Wire lock between jam nut and outer casing sleeve in a figure eight configuration.

(11) Detach clevis end from control cambox input arm.

(12) Fit attachments to control cable at centre wing as follows:-

Jam nut, mounting bracket (with swivel abutment attached) second jam nut, gland nut, stiffnut (reverse fit) and eye end.

NOTE: 1. When attaching swivel abutment to mounting bracket ensure that replacement split pins are fitted.

2. When attaching stiffnut and eye end ensure that control orientation is maintained by use of the spanner flats.

(13) Temporarily attach eye end to lower quadrant output lever.

(14) Temporarily attach mounting bracket to structure at wing Stn. 45.

(15) Adjust control cable outer casing to suit cable travel by use of the jam nut.

(16) Maintain setting as follows:-

(a) Position jam nut against swivel abutment bearing.

(b) Ensure gland nut wire locking hole is aligned with groove in cable outer casing. Fit split pin.

(c) Wire lock between jam nut and gland nut split pin in a figure eight configuration.

(d) Detach mounting bracket from structure, withdraw outer casing toward eye end, exposing remaining jam nut.

(e) Position jam nut against swivel abutment bearing.

(f) Wire lock between jam nut and outer casing sleeve, in a figure eight configuration.

(g) Return outer casing to original position and re-attach mounting bracket to structure.

(17) Detach eye end from lower quadrant output lever.

(18) Attach cable housing ferrules at wing Stns. 68.8 and 83.5 along with four bolts, washers and nuts retained on removal.

NOTE: On installation of each ferrule, check for cable security and free movement.

(19) Position seal and sealing plate over cable on outboard side of wing stn. 106.5, and secure to structure with two bolts, washers and nuts retained on removal.

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(20) Attach cable securing clips (six-left installation or seven-right installation) in position as noted during removal, with bolts, washers and nuts.

NOTE: On installation of each clip, check for cable security and free movement.

(21) Measure the rolling friction of the cable, checking that load does not exceed 20 oz.

(22) Attach clevis end at control cambox input arm, and eye end at lower quadrant output lever (fitting washers as noted on removal). Torque tighten to 10 lb. in. and fit replacement split pins.

(23) Remove rigging pin M-6-P or M-6-S as appropriate.

(24) Function check the control cable as follows:-

(a) Move the associated power control lever (pilots console) forward, checking that the follower lever on the control cambox adopts the 'max power' position. Refer to 76-10-00, Figure 501.

(b) Return power lever to FLIGHT IDLE position, checking that follower lever adopts same.

(25) Refit access panels, checking that lower engine cowl does not foul control cable on closing.

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AMM76-13-00 7.0.0.0AUTOMATIC TAKE-OFF POWER CONTROL SYSTEM (RESERVE POWER)DESCRIPTION & OPERATION

1. Description

A. General

When armed (observing limitations), the ATPCS system will automatically increase the selected MTOP of an operating engine to Reserve Take-off Power (RTOP) should the opposite engine fail during a continued take-off.

Power increase is initiated by the fuel control units NG reset servo mechanism which essentially comprises a bellofram piston and a speed reset eccentric shaft.

Refer to Figure 1. The piston is activated by restricted P3 bleed air, trapped from the supply to the FCU P3 sensor and delivered via a reserve power solenoid valve. The piston, thus operated, will cause the eccentric to reposition the 3D cam follower pivot point such that rotational movement of the fuel valve accompanied by engine response (P3 sensor) axial movement will occur; the resultant increase in metered fuel flow will cause Ng to rise by approximately 3%.

A bleed orifice permits return of the piston under spring-action when the solenoid valve is closed subsequent to operational or test use of the system.

B. Equipment

Refer to Figure 2.

(1) Reserve power solenoid valves

The valves are idented QJ2 and for each engine are located adjacent to the fuel control unit. They are controlled in conjunction with the air-conditioned bleed valves by relays on panel 1C and 2C such that when a reserve power valve opens, the associated engines air-conditioning bleed closes to conserve power.

(2) Torque pressure switches

A torque pressure switch, idented QJ10, is located on a pressure switch manifold attached to the right side of the engine mounting frame (aft of rear fireshield). The switch contacts are made when torque pressure falls below 12 psi (equivalent to 1000 1b ft).

(3) Power lever switches

These are idented 1QJ1 - left and 2QJ1 - right and are located at the forward end of the flight compartment centre console.

The switch contacts are made when the associated power levers are advanced to positions relative to at least 90% Ng.

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C. Controls and indication

Refer to Figure 2.

(1) Control switches

The system is controlled by two RESERVE POWER switches on the ENGINES Section of Panel 4P; each switch has two positions, OFF/ARM.

(2) Test switches

Two RESERVE POWER test switches, one left and one right are provided on panel 11P. They are connected in parallel with their associated power lever switches so that engine running operational checks may be performed at lower power settings.

(3) System indication

Two indicator modules (one left, one right) are presented on main instrument panel 1P; each comprises upper and lower captioned sections, respectively bearing the legends RTOP ON and RTOP ARM.

For each module, operational indication appropriate to system condition is as follows:-

2. Operation

A. System Tests

Refer to 76-13-00, pb201.

(a) Both captions 'out' associated control switch OFF or related power lever below 90% Ng with control switch set at ARM.

(b) RTOP ARM caption lit associated control switch and power lever at respective settings of ARM and 90% Ng or greater, and opposite engine torque pressure in excess of 12 psi.

(c) RTOP ON caption lit If opposite engine torque pressure falls below 12 psi subsequent to condition (b).

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Reserve Power - Principle of OperationFigure 1

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B. System Operation

If required for the flight, both RESERVE POWER switches on the Engines section of Panel 4P are set to ARM before performing the critical flight phase of take-off.

When power levers are advanced to position at or beyond that relative to 90% Ng, the system indicators will display RTOP ARM. Subsequent failure of either engine will cause the related torque pressure switch to operate when the true torque falls below 12 psi (1002 1b ft). This completes a circuit to energize the control relay in the other engine circuit, causing the following with respect to the live engine:-

(1) Opens the reserve power solenoid valve (thus activating the fuel control units Ng reset servo mechanism).

(2) Changes the appropriate indicator display to RTOP ON from RTOP ARM.

(3) Closes the air-conditioning hot air bleed valve to conserve power.

Power increase above that manually scheduled will be maintained until (a) the associated power lever is retarded below 90% Ng or (b) the associated control switch is set OFF.

3. Power supplies

The system operates on 28 V dc; supplies being made available from the left and right Essential Services Busbar via respective 5A C/B Nos. 104 and 251 on Distribution Panels 1D and 2D.

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Controls & Equipment - Reserve Power SystemFigure 2

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Reserve Power Control - SchematicFigure 3

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AMM76-13-00 8.0.0.0AUTOMATIC TAKE-OFF POWER CONTROL SYSTEM (RESERVE POWER)MAINTENANCE PRACTICES

1. Function test the system

NOTE: To effect complete function test of the system, perform the procedures detailed in para A and B in turn.

A. Function the system

Refer to 71-00-00, pb1.

(1) Start both engines.

(2) Refer to System Checks detailed therein and carry out that for the Reserve Power System.

(3) Set airconditioning bleeds OFF.

(4) Leave left power levers at FLIGHT IDLE and advance right power lever to obtain a steady 90% Ng. Apply a pencil line at the aft edge of the right power lever across the console slot to identify the 90% Ng position.

(5) Repeat (4), reading right for left and left for right.

(6) Shutdown engines.

B. Check rigging of the appropriate power lever switches.

(1) Refer to 12-09-03, pb301. Energize the Left and Right Essential Services busbars.

(2) Close C/B Nos 104 and 251 on respective distribution panels 1D and 2D.

(3) Remove power lever 'max-taxi' balk (select flying controls locking handle to the UNLOCKED position).

(4) Check rigging of the left switch as follows:-

(a) Position left power lever at FLIGHT IDLE.

(b) Select left RESERVE POWER switch on panel 4P to ARM.

(c) Slowly advance power lever from FLIGHT IDLE and check that immediately the aft edge of the lever coincides with the 90% Ng pencil mark on the console cover, the left RTOP ON caption on panel 1P illuminates. Further advance power lever to max. power stop, checking that module display is maintained.

(d) Return the power lever to FLIGHT IDLE, checking that the RTOP ON caption extinguishes immediately the aft edge of the lever passes the 90% Ng mark.

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(5) Repeat (4), reading right for left to effect rigging check of right switch.

NOTE: Rigging adjustments required. Refer to 76-13-01, pb201.

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AMM76-13-01 9.0.0.0POWER LEVER SWITCHES - RESERVE POWER SYSTEM MAINTENANCE PRACTICES

1. Adjustment/Test

A. Function test the switches.

The switches are confirmed operational upon satisfactory completion of the following functional test. Refer to 76-13-00, pb1.

B. Adjust the switches

Refer to Figure 201.

Special tools and equipment:-

- Continuity Tester

(1) Open C/B Nos. 104 and 251 on respective distribution panels 1D and 2D.

(2) Select flying controls locking handle to the forward (unlocked) position.

(3) Advance each power lever so that the 90% Ng pencil marks on the console cover coincide with the aft edge of each lever. Maintain this setting employing the friction damper knobs.

(4) Refer to Figure 201. Locate the microswitches, idented 1QJ1 and 2QJ1 (located at forward lower end of centre console) and rig as detailed in (5) or (6) as appropriate.

NOTE: (a) Operation (5) details procedure employing only the switch positioning (trimming) screws to set operation.

(b) Operation (6) details procedure where operating cam positions have been disturbed.

(5) Rig each microswitch in turn as follows:-

(a) Adjust switch trimming screw such that its actuating roller is clear of the associated operating cam.

(b) Slacken switch positioning screw until switch operates i.e. continuity between switch associated terminals on TB10 is achieved. Refer to Table 201.

(c) Release the friction damper knob and advance appropriate lever to max. power stop, checking that continuity continues throughout the travel.

(d) Retard the power lever, checking that continuity is broken as the aft edge of the lever passes the pencil mark on the console cover.

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(6) Rig each microswitch in turn as follows:-

(a) Slacken the associated microswitch operating cam clamping attachments, and rotate cam lever clear of microswitch roller.

(b) Adjust switch trimming screw to place switch body in vertical position with respect to its pivot.

(c) Carefully rotate the operating cam against the switch roller until continuity is achieved between switch associated terminals on TB 10. Refer to Table 201. Tighten clamp attachments and lock with split pin.

(d) Release the friction damper knob and advance appropriate lever to max. power stop, checking that continuity continues throughout the travel.

(e) Retard the power lever, checking that continuity is broken as the aft edge of the lever passes the pencil mark on the console cover.

(7) Return both power levers to the FLIGHT IDLE position.

(8) Select the flying controls locking handle to the locked position.

(9) Close C/B Nos. 104 and 251.

Table 201

LEFT PWR LEVER

SWITCH

CONTINUITY CHECKAT TB10 RIGHT PWR

LEVER SWITCH

CONTINUITY CHECKAT TB10

Pwr Lever At/Above 90% Ng

Pwr Lever BELOW 90% Ng

Pwr Lever At/Above 90% Ng

Pwr Lever BELOW 90% Ng

1QJ1 2QJ1YES (5&6) NO (5&6) YES (7&8) NO (7&8)

TERMLS TERMLS TERMLS TERMLS

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Reserve Power Throttle MicroswitchesFigure 201