SD3-60 AIRCRAFT MAINTENANCE MANUAL PRIMARY CONTROLS - DESCRIPTION & OPERATION

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Rudolph Hawkins
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1 AMM AILERON PRIMARY CONTROLS - DESCRIPTION & OPERATION 1. Description A. General Aileron movement is differentially controlled by a system of push/pull rods and levers which directly connect the control handwheels in the flight deck with the inner hinge arm on each aileron. The ailerons are each provided with a trim tab and an associated control system. Refer to , pb1. The tabs also act in a geared capacity i.e. they respond to assist primary control surface movement. B. Aileron circuit Refer to Figure 1. Each of the control column mounted handwheels is connected by chains to two linked quadrants at the base of the column. A control rod from the inboard end of each quadrant link rod picks up on the lower lever of a torque assembly mounted within the forward end of the flight deck centre console. From the upper lever on the torque tube, the run continues (rising within a vertical duct positioned centrally at the rear of the flight deck) to pick up on a bell-crank lever mounted in the fuselage roof structure on the aft face of frame 74. A series of control rods, routed through the roof structure immediately to the right of the aircraft centre-line, connect the bell-crank to a lever assembly positioned approximately 6 in. to the rear of the front spar. From the 'short-radius' (output) hole in the lever a control rod connects to a lever on the bottom of a torque tube assembly which penetrates the fuselage top skin (on the aircraft centre-line, approximately 7 in. aft of the rear spar). The upper end of the torque tube projects into the centre-section wing fairing. Two levers fitted to the top of the torque tube, in common with two further double lever assemblies (mounted left and right within the fairing) are designed such that together with 'overlapping' of the interconnecting control rods - the control runs in the left and right wings operate simultaneously through differing linear ranges. This arrangement provides differential travel of the control surfaces i.e. greater up movement of an aileron compared with the down movement of the opposite surface. The control run within each wing extends outboard along the rear spar to pick up the input arm of a cranked operating lever which is positioned immediately inboard of the aileron inner hinge arm support bracket. The output arm on the lever is connected by an operating rod to the aileron hinge arm. Page 1 Jun 30/01

2 Aileron Primary Controls Figure 1 Page 2 Jun 30/01

3 C. Aileron stops Fixed primary and adjustable secondary stops which determine the range of surface travel are respectively provided - (a) within each control column head (b) at the left and right aileron outboard hinge. When the appropriate primary stops take effect a clearance exists at the corresponding secondary stop. NOTE: Each secondary stop limits the upward movement of the associated aileron beyond that determined by the primary stops and in so doing will also limit the down movement of the opposite aileron. Page 3 Jun 30/01

4 AMM AILERON PRIMARY CONTROLS - MAINTENANCE PRACTICES DUPLICATE INSPECTION WHENEVER ANY PART OF THIS SYSTEM IS DISMANTLED, ADJUSTED, REPAIRED OR RENEWED, DETAILED INVESTIGATION MUST BE MADE ON COMPLETION TO ENSURE THAT DISTORTION, TOOLS, RAG OR ANY OTHER 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. 1. Servicing A. Lubrication Routine lubrication data. Refer to , pb Adjustment/Test Special tools and equipment:- Outer wing profile board Clamp type travel gauge Rigging pins (as listed) A1(two off) A2 A3 A4 A5 A6 A7 A8 (two off) T T or equivalent T T T T T T T T Page 201

5 A. Rig the controls Refer to Figure 201 (Sheet 1). Carry out the following procedures with respect to local linkages throughout the system to effect complete rigging of the aileron primary controls. NOTE: After final adjustment of control rod lengths, check that the rod ends are in safety i.e. threads in evidence through inspection holes, and lock the adjustable fittings with the nut and tab washers. Rig between control columns and bottom of duct (fr. 74). (1) With reference to details A, B and C, disconnect control rods SD , SD and SD at adjustable ends. (2) Select controls locking handle (centre console) to LOCKED and manually position the lever assembly shown on detail D such that locking mechanism engages. (3) Insert rigging pins A1 (details A and B) and A2 (detail C). (4) Adjust the control rods as necessary and reconnect to their resepective levers. Rig between bottom of duct (fr. 74) and torque tube aft of rear spar. (5) With reference to main view, disconnect controls rods SD , 2129, 6019, 6018, 2130 and 2131 at adjustable ends. (6) Insert rigging pins A3, A4 and A5 where shown respectively on details E, F and G. (7) Set the fixed length control rod SD , 2450 and 2448 (see main view) at their aft ends to the dimension quoted on detail N. Maintain this setting and adjust control rods disconnected at (5) to suit and reconnect. (8) Set clearance at each roller guide support (detail M) as follows:- (a) Remove all rigging pins and select controls UNLOCKED. (b) Disconnect control rods SD , left and right where attached to torque tube (detail G). (c) Operate control handwheel throughout range to determine tightest point on adjustable roller; set roller to provide in. clearance at this point. Tighten clamping block. (d) Again operate throughout range, checking that no gap exceeds in. Wirelock clamping block bolt. (e) Select controls LOCKED; centralie handwheels to ensure engagement. Page 202

6 Rig between centre-section torque tube and outer wing linkages. (9) Disconnect the left and right control rods SD , 2133 and 2134 within the centresection and wing (see main view) at their adjustable ends. (10) Insert rigging pins A5 - detail G, A6 - detail H, A7 - detail J, A8 - details K and L. (11) With reference to detail N, set the three left and three right fixed length control rods SD to the dimension shown. Maintain this setting, adjust control rods disconnected at (9) to suit and reconnect between fixed rods and lever assemblies. (12) Disconnect control rods SD , left and right (details K and L) and set clearance of each roller guide support (detail M) in the manner detailed at (8) for those within fuselage roof. (13) Re-insert rigging pins referred at (10). Rig between outer wing linkage and aileron. (14) With reference to detail K - left and L - right, disconnect control rod SD (15) Place profile board on outer wing at approximate centre of aileron. Bring control surface into contact with board, adjust rod SD to suit and reconnect (do not lock attachments). Remove boards. (16) Connect clamp type travel gauges to the trailing edges of the left and right surfaces and adjust to register ero. NOTE: Steps (17) and (18) which follow apply only to aircraft production Ser. Nos prior to SH (17) Further adjust control rods SD such that surfaces adopt an angle of 3 deg. down (neutral position). (18) Reset travel gauges to ero. (19) Remove all rigging pins and select controls UNLOCKED. (20) Screw in adjustable stops at control surfaces such that no impedance will be offered to full control column handwheel movement. Page 203

7 Aileron Controls - Rigging Figure 201 (Sheet 1) Page 204

8 Aileron Controls - Rigging Figure 201 (Sheet 2) Page 205

9 Aileron Controls Rigging Figure 201 (Sheet 3) Page 206

10 (21) Refer to Figure 201 (Sheet 1). Rotate the handwheel anti-clockwise to the full extent of its travel and check the travel of the left and right surfaces as appropriate to aircraft production Ser. No. Adjust and lock the stop at the left aileron to provide the clearance shown on detail P. (22) Repeat (21) with handwheel moved fully clockwise and again with reference to detail P - adjust and lock the stop at the right aileron. Complete the rigging procedure (23) Remove travel gauges. (24) Check backlash and circuit friction as detailed in para 3. (25) Select controls LOCKED and check that all rigging pins can be inserted and withdrawn freely. Remove rigging pins. B. Function test aileron primary controls. (1) Select controls LOCKED. (2) Attach travel gauges centrally to trailing edge of left and right aileron. Adjust to register ero. (3) Refer to Figure 201 (Sheet 1). Select controls UNLOCKED and operate handwheels to extremes of travel in both directions, checking that the control surface movement and sensing agrees with the table on the figure in each instance. 3. Inspection/check A. Check rigging Refer to Figure 201 (Sheet 1). (1) Insert rigging pins A1 as shown on details A and B. (2) Check that when controls are selected LOCKED, the locking lever (detail D) enagages. (3) Remove rigging pins and perform function test detailed in para 2.B. and additionally check the cearances at the control surface stops (detail P) when the handwheel stops take effect. B. Check backlash (1) Suitably lock handwheels in neutral position. NOTE: Do not employ gust lock mechansim for this purpose. Page 207

11 (2) Check backlash by applying a load of 2 lb at the trailing edge of an aileron, first in an upward direction, then in a downward direction. The total backlash should not exceed 1 deg. (3) Repeat (2) for opposite aileron. C. Check circuit friction (1) Connect a spring balance to the top of the handwheels left hand-grip. (2) Place the handwheel in the neutral position. (3) Refer to Figure 201 (Sheet 1). Slowly pull the handwheel clockwise, maintaining the load tangential to the handwheel travel and check that a sustained load of not more than 3.7 lb is sufficient to initiate and complete the appropriate control surface travels shown on the figure. (4) Repeat (2) and (3) for anti-clockwise movement i.e. spring balance connected to righthand grip. Page 208

SD3-60 AIRCRAFT MAINTENANCE MANUAL & RETRACTION - DESCRIPTION & OPERATION

SD3-60 AIRCRAFT MAINTENANCE MANUAL & RETRACTION - DESCRIPTION & OPERATION AMM 17.0.0.0EXTENSION & RETRACTION - DESCRIPTION & OPERATION 1. Description A. General The landing gear is extended and retracted by the operation of a hydraulic actuator at each of the main and nose gear