ATA 27 Flight Controls - Issue 6 January 2023 PDF

BOMBARDIER DHC 8-400 (PWC PW150) ATA 27 - FLIGHT CONTROLS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS PURPOSE The flight controls keep the aircraft at the necessary atti...

BOMBARDIER DHC 8-400 (PWC PW150) ATA 27 - FLIGHT CONTROLS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS PURPOSE The flight controls keep the aircraft at the necessary attitude during flight. They have moveable surfaces on the wing and the empennage. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 2 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS INTRODUCTION The flight controls consist of: • • • • • Aileron roll control system Rudder yaw control system Elevator pitch control system Flap control system Flight control electronic control unit TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 3 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM PURPOSE The aileron system transmits the roll commands from either the autopilot or the pilot and copilot control hand-wheels to the aileron control surfaces. GENERAL DESCRIPTION The aileron system transmits the roll commands from the pilot and copilot control hand-wheels to the aileron surfaces through a series quadrants, cables, levers and pushrods. Movement of the control hand-wheels causes the aileron surfaces to deflect asymmetrically and in proportion to control hand-wheel rotation. The aileron system also has inputs from the Auto Flight Control System (AFCS) and the Aileron Trim and Centring Unit. The aileron system has the components that follow: • • • • • Aileron Forward Quadrant Aileron Splitter Quadrant Aileron Terminal Quadrant Aileron Geared Tab Aileron Position LVDT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 4 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON CONTROL SYSTEM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 5 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM SIMPLIFIED DESCRIPTION Rotary movement of the copilot control hand-wheel is transmitted by a sprocket and chain mechanism to a sprocket and lever assembly at the base of the copilot control column. A pushrod connects the lever to the aileron forward quadrant below the flight compartment floor. The sprocket and lever assembly at the base of the copilot control column has a clutch which is used for roll disconnect purposes. A roll disconnect ROLL DISC handle located at the forward centre console operates the clutch. When the handle is in the clutch is engaged. This connects the aileron circuit to the spoiler circuit to give synchronized movement of both hand-wheels. The Aileron Trim and Centring Unit have a trim actuator and a torsion spring bar connected to the aileron forward quadrant by levers and a pushrod. The autopilot servo is also connected to the aileron forward quadrant by a cable and a clutched capstan. Aileron control cables are routed aft from the aileron forward quadrant, up the forward face of the flight compartment bulkhead and aft along the cabin roof. The cables then pass through pressure seals in the cabin roof to terminate at the aileron splitter quadrant on the aft face of the wing rear spar. Left and right aileron control wing cables are routed outboard from the aileron splitter quadrant, one cable loop along each wing. Each aileron control wing cable then terminates at an aileron terminal quadrant located on the aft face of the wing rear spar. Aileron terminal quadrant movement is transmitted to the aileron by a pushrod. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 6 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON CONTROL SYSTEM SYNOPTIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 7 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM AILERON FORWARD QUADRANT PURPOSE The aileron forward quadrant transmits inputs from the copilot control Hand-wheel to the aileron splitter quadrant. The quadrant also has flight control input from the autopilot and the Aileron Trim and Centring Unit. The aileron forward quadrant is installed in the right side of the lower forward fuselage, below the flight compartment floor. The quadrant has two pulleys with secondary travel stops and a lever assembly all installed on a single shaft. Two mounting brackets attach the aileron forward quadrant to the lower forward fuselage. A pushrod connects the lever at the base of the copilot control column to the lever on the aileron forward quadrant. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 8 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON FORWARD QUADRANT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 9 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM AILERON SPLITTER QUADRANT PURPOSE The aileron splitter quadrant transmits aileron cable inputs from the copilot control hand-wheel to the aileron terminal quadrants located in each wing. The splitter quadrant is installed on the aft face of the wing rear spar. The quadrant has three pulleys installed on a common shaft. The centre pulley has a removable fitting with two cable retaining holes. The holes for the top and bottom pulleys are inset. Gust locking of the ailerons is supplied by an internal spring-loaded lever attached off-centre to the bottom of the splitter quadrant. When the gust lock is engaged a plunger is inserted in the gust lock plate at the base of the splitter quadrant, locking the ailerons in neutral. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 10 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON SPLITTER QUADRANT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 11 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM AILERON TERMINAL QUADRANT PURPOSE The terminal quadrant transmits aileron cable control from the aileron splitter quadrant to the aileron surface. There are two aileron terminal quadrants, one in each wing. Each aileron terminal quadrant is located on the wing rear spar adjacent to its related aileron. The aileron terminal quadrant is the last quadrant in the control linkage from the copilot control column to the aileron. The quadrant is connected to the aileron by a lever and a control rod. For rigging procedures, a 0.25 in/6.35 mm rig pin hole is used to lock the quadrant in neutral. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 12 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON TERMINAL QUADRANT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 13 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM AILERON GEARED TAB PURPOSE Each aileron has a geared tab, which gives aerodynamic assistance to movement of the aileron control surface. The aileron geared tab is attached by four hinge fittings to the trailing edge of each aileron. The tab is connected to the aileron by a geared linkage so that the geared tab moves 70% of the total aileron movement. At full aileron deflection of 17°, the aileron geared tab deflects 11.9° in the opposite direction. This action gives aerodynamic assistance and reduces the force required to turn the control hand-wheels. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 14 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON GEARED TAB TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 15 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM AILERON POSITION LVDT PURPOSE A Linear Variable Differential Transformer (LVDT) monitors the position of the ailerons. The LVDT monitors the position of the ailerons by supplying an electrical signal equivalent to the angular position of the flight control surface to the FCECU. The FCECU supplies electrical excitation of the LVDT. The reply signal voltage is processed by the FCECU and transmitted to the Flight Data Recorder (FDR) by way of the Integrated Flight Cabinet (IFC) No.1 on an ARINC 429 Data Bus. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 16 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON LINEAR VARIABLE DIFFERENTIAL TRANSFORMER (LVDT) TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 17 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM AILERONS TRIM AND CENTRING PURPOSE Aileron trim counters the effects of lateral imbalance. INTRODUCTION Aileron trim counters the effects of lateral imbalance. Lateral imbalance may be due to uneven fuel distribution, asymmetric power, or any other forces that affect the lateral axis of the aircraft. GENERAL DESCRIPTION Aileron trim is achieved by electrically trimming both aileron surfaces through the actuator located in the Aileron Trim and Centring Unit. The trim and centring unit is connected to the aileron forward quadrant by a spring torsion bar that makes sure the aileron surfaces always return to a neutral position. The aileron trim and centring system has the components that follow: • • • Trim Actuator Centring Unit Trim-Ground Adjustable Tab TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 18 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON TRIM AND CENTERING UNIT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 19 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS The aileron trim and centring system has a spring torsion bar attached to the aileron forward quadrant by a lever and a pushrod. Movement of the CONTROL hand-wheels causes rotation of the aileron forward quadrant and twisting of the spring torsion bar. The twist in the spring torsion bar makes sure that the ailerons return to the trimmed neutral position after any control hand-wheel rotation. AILERON SYSTEM AILERONS TRIM AND CENTRING SIMPLIFIED DESCRIPTION The aileron trim and centring system transfers input commands from the aileron trim actuator to the aileron forward quadrant through the torsion bar. The forward quadrant rotates and transfers the trim command to the ailerons through the aileron control circuit. Aileron trim is achieved by deflecting both aileron control surfaces. The amount of aileron trim is controlled by the AILERON trim switch on the TRIM panel located in the flight compartment on the centre console. The amount of trim is shown on the AIL TRIM LWD-RWD indicator located on the aileron and rudder TRIM control panel. When the autopilot is engaged, a message MISTRIM - TRIM L WING DN or TRIM R WING DN is shown on the Primary Flight Display if aileron trim is required. The pilot then applies trim using the AILERON trim switch until the control forces are removed from the Autopilot servo. An aileron trim indicator, located on the TRIM panel. in the centre console shows aileron trim position. The aileron trim indicator receives its information from a Linear Variable Differential Transformer (LVDT) which is located inside the aileron trim actuator. The LVDT also transmits aileron trim position data to the IOP No.1. Power: 28V DC left ESS, Aileron Trim Ind, 5 amps. The AILERON trim switch located on the aileron and rudder TRIM control panel gives electrical control of the aileron trim actuator. The aileron trim switch has three positions: • • • LWD (left wing down) RWD (right wing down) Centre-off The switch is spring-loaded to return to the centre-off position to reduce the possibility of accidental operation. Selection of the LWD position extends the aileron trim actuator and turns the torsion bar, which turns the aileron forward quadrant, causing both aileron surfaces to move differentially. Selection of the RWD position reverses the process, causing the ailerons to move in the opposite direction. NOTE: Gust lock must be disengaged. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 20 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON TRIM SWITCH AND INDICATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 21 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM TRIM ACTUATOR PURPOSE The trim actuator drives the aileron control system to counter the effects of lateral imbalance. The trim actuator is a part of the Aileron Trim and Centring Unit. The AILERON trim switch located on the aileron and rudder TRIM control panel gives electrical control of the aileron trim actuator. The pilot controls the amount of aileron trim by operating the AILERON trim switch which supplies the electrical signal to the aileron trim actuator. Selection of the LWD position extends the aileron trim actuator which turns the torsion bar, and turns the aileron forward quadrant, causing both aileron surfaces to move deferentially. Selection of the RWD position reverses the process, causing the ailerons to move in the opposite direction. If the AILERON trim switch fails to the closed position, a limit switch on the trim actuator housing opens the electrical circuit and causes the trim actuator to stop at the maximum trim input. If the limit switch fails to stop the trim actuator, a mechanical stop on the trim actuator housing stops the trim actuator at the maximum trim setting. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 22 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON TRIM ACTUATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 23 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM CENTRING UNIT PURPOSE The centring unit makes sure that the ailerons return to the trimmed neutral position after any control hand-wheel rotation. The centring unit is part of the Aileron Trim and Centring System. It has a spring torsion bar that links the aileron trim actuator to the forward quadrant. An input to the control hand-wheel turns the forward quadrant, which displaces the aileron surfaces. A torsional load is applied on the spring torsion bar. When the input to the hand-wheel is released, the load on the torsion bar causes the control hand-wheel to return to a trimmed neutral position. This control hand-wheel centring action reduces the workload of the pilot or copilot. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 24 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON CENTERING UNIT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 25 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM TRIM-GROUND ADJUSTABLE TAB PURPOSE The ground adjustable trim tab is used to adjust for any aerodynamic asymmetry between the left and right ailerons due to manufacturing tolerances. The ground adjustable trim tab is located on the trailing edge of the right aileron, inboard of the geared tab. The adjustment is made on the serrated plate, at the tab end of the geared linkage. The trim tab is adjusted by maintenance personnel after a test flight and only as required thereafter. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 26 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - GROUND ADJUSTABLE TRIM TAB TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 27 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON TRIM SYSTEM ELECTRICAL BLOCK SCHEMATIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 28 of 340 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 29 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS The right hand aileron has a ground adjustable trim tab located inboard of the aileron geared tab. AILERON SYSTEM AILERON CONTROL SURFACES AILERON SURFACES Each aileron is attached to the trailing edge of its related wing by four hinge fittings. View holes are located on the bottom of the aileron for visual inspection of the hinge pins. An access panel is located at the centre hinge point. A horn with internal mass balance weights is located on the outboard end of each aileron to give aerodynamic balance. PURPOSE The aileron surfaces are the primary flight control for lateral control. INTRODUCTION The aileron surfaces assisted by the roll spoilers give roll (lateral) control of the aircraft in flight. GENERAL DESCRIPTION There are two aileron control surfaces. One is installed on the outboard end of the left wing and the other is installed on the outboard end of the right wing. Each aileron surface forms part of the trailing edge of its respective wing. Each aileron has a geared tab, which gives aerodynamic assistance to the aileron control surface. The aileron geared tabs are attached by four hinge fittings to the trailing edge of each aileron. The tab geared linkage is connected to the aileron hinge point to give controlled tab movement, in proportion to aileron movement. The geared linkage has one link, one end connected to the geared tab hinge, the other end to the aileron hinge point. Each geared tab has adjustable bolts located on the hinge arm of the tab. The right aileron has a ground adjustable trim tab located inboard of the geared tab. The adjustment is made on the serrated plate, at the tab end of the geared linkage. The Aileron Surfaces have the components that follow: • Aileron Control Surfaces SIMPLIFIED DESCRIPTION Each aileron control surface can travel ±17° around the neutral position. At airspeeds above 170 kts/315 km/h, the ailerons and the inboard roll spoilers give sufficient lateral control of the aircraft. At airspeeds below 170 kts/315 km/h, the ailerons are assisted by both the inboard and the outboard roll spoilers. Each aileron has a geared tab that gives aerodynamic assistance to the movement of the aileron surfaces in flight. The geared tab also helps to overcome the load put on the control wheels by the torsion bar in the aileron trim and centring unit. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 30 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON SURFACES DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 31 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS rod. The roll disconnect system has a horizontally mounted ROLL DISC handle located on the right side of the forward centre console. AILERON SYSTEM The handle is connected to a clutch mechanism located at the base of the copilot control column by cables, pulleys and a spring loaded lever assembly. ROLL DISCONNECT SYSTEM PURPOSE The roll disconnect system disengages the ailerons from the roll spoilers. INTRODUCTION The roll disconnect system disengages the aileron and roll spoiler control circuits from each other in the event of a jam in either control circuit. The remaining operational circuit maintains roll lateral control of the aircraft. The cables between the handle and clutch mechanism are routed under the flight compartment floor. The system is adjusted by loosening or tightening turnbuckles, one in the forward roll disconnect cable and one in the cable from the lever assembly to the clutch mechanism. If a roll jam occurs in either system, the handle is pulled out to the limit and turned through 90°. This action isolates the jammed system from the operating system. The un-jammed wheel is now used to maintain roll control of the aircraft. GENERAL DESCRIPTION The pilot control hand-wheel operates the spoiler control circuit and the copilot control hand-wheel operates the aileron control circuit. The control hand-wheels are connected to each other so that either control hand-wheel operates both circuits at the same time. This lets the aircraft be flown from either the pilot or copilot position. If either control circuit becomes jammed, the ROLL DISC handle is pulled to disconnect the aileron system from the roll spoiler system. The pilot with the un-jammed control hand-wheel maintains roll control of the aircraft. The roll disconnect system has the components that follow: • • • Roll Disconnect Handle Roll Disconnect Lever Assembly Roll Disconnect Clutch Mechanism SIMPLIFIED DESCRIPTION The aileron and roll spoiler control circuits are joined to each other by an interconnect TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 32 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - ROLL DISCONNECT SYSTEM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 33 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM ROLL DISCONNECT HANDLE PURPOSE The roll disconnect handle is used to operate the roll disconnect system. The ROLL DISC handle is located in the flight compartment, on the copilot side of the forward centre console. The handle is used to separate the controls of the aileron and spoiler systems. The roll disconnect handle is normally in the engaged position. The handle is connected to a clutch mechanism at the base of the copilot control column by cables, pulleys, and a spring-loaded lever assembly. The roll disconnect mechanism is disengaged when the roll disconnect handle is pulled to the stop and rotated by 90° in either direction. A pin in the shaft of the roll disconnect handle, rides in a slot in the shaft housing. When the handle is pulled out to the limit and rotated 90°, the pin slides into the slot to keep the handle locked in the disengaged position. The roll disconnect mechanism is re-engaged when the pilot and copilot hand-wheels are moved to the same position, the roll disconnect handle is rotated 90° and released. The spring on the clutch mechanism pulls the handle back to the engaged position. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 34 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - ROLL DISCONNECT HANDLE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 35 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM ROLL DISCONNECT LEVER ASSEMBLY PURPOSE The roll disconnect lever assembly is used to gain mechanical advantage over the clutch mechanism. The roll disconnect lever assembly is located below the flight compartment floor near the base of the copilot control column. The lever assembly is attached by a cable to the roll disconnect handle. Another cable attaches the lever to the engagement spring cover of the clutch mechanism. When the roll disconnect handle is pulled, the lever assembly rotates and pulls the engagement spring cover, which causes the clutch to disengage. At the same time, the rotating lever assembly closes two micro-switches which are a part of the roll spoiler advisory light circuit. A return spring attached to the lever assembly keeps the tension off the cable joining the lever assembly to the clutch mechanism. This prevents the clutch from accidentally disengaging and helps to return the roll disconnect handle to the engaged position. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 36 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - ROLL DISCONNECT LEVER ASSEMBLY TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 37 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS The handle and clutch mechanism return to the engaged position by the action of the return and engagement springs. The lever and clutch plate assembly re-engages with the clutch lever and sprocket assembly when the two control wheels come into alignment. The engagement spring keeps the clutch in the engaged position. AILERON SYSTEM ROLL DISCONNECT CLUTCH MECHANISM PURPOSE The roll disconnect clutch mechanism connects the roll control of the copilot control wheel to the roll control of the pilot control wheel. The roll disconnect clutch mechanism is attached to the base of the copilot control column. When the clutch mechanism is in the engaged position, it connects the chain drive of the copilot control wheel through an interconnect rod to the pilot control wheel. When disengaged by the roll disconnect handle in the flight compartment, the clutch mechanism separates the copilot column from the interconnect rod. The roll disconnect clutch mechanism consists of an engagement spring, an engagement spring cover and a clutch. The clutch is made up of two halves: • • Clutch and sprocket assembly Clutch plate and lever assembly The chain in the copilot control column rotates the sprocket and clutch assembly, which drives the clutch plate and lever assembly when in the engaged position. The lever part of the clutch plate and lever assembly is attached to the pilot control column through the interconnect rod. The interconnect rod is the link which transfers aileron and spoiler control between the pilot and copilot control columns. When the roll disconnect handle is pulled to the limit and turned 90°, the clutch plate and lever assembly is separated from the clutch and sprocket assembly. This action lets the control hand-wheels rotate independently of each other. To reengage the clutch, the handle must be rotated 90° and released. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 38 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - ROLL DISCONNECT CLUTCH MECHANISM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 39 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS AILERON SYSTEM ROLL DISCONNECT CLUTCH MECHANISM INTERFACES The roll disconnect system is interfaced with the roll spoiler advisory switch-lights (SPLR1 and SPLR2) on the centre glare-shield panel. The SPLR1 and SPLR2 switchlights are located on the centre glare-shield panel. When the roll disconnect handle is pulled, two micro-switches are closed by the roll disconnect lever assembly. If the copilot control hand-wheel is rotated more than 50° to overcome the effects of a jammed spoiler control system, the aileron quadrant also closes the 50° travel microswitch. This micro-switch is located on the aileron forward quadrant. When the roll disconnect arm micro-switch is activated and one of the 50° switches is activated, then the SPLR1 or SPLR2 switch-light comes on indicating a jammed spoiler. The pilot then pushes the two switch-lights, which depressurizes the spoiler PCU allowing the jammed spoiler panel(s) to retract flush with the wing surface. This will cause the appropriate caution lights to illuminate: • • ROLL SPLR INBD HYD ROLLSPLROUTBHYD TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 40 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - AILERON FORWARD QUADRANT MICROSWITCH TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 41 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - SPOILER PUSHOFF SWITCH-LIGHTS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 42 of 340 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 43 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM PURPOSE The rudder system transmits the yaw commands from the pilot and copilot rudder pedals to the rudder control surfaces. INTRODUCTION The rudder system transmits the yaw commands from the pilot and copilot rudder pedals to the rudder control surfaces. The rudder surfaces are moved in proportion to the amount of rudder pedal input. GENERAL DESCRIPTION The rudder system transmits the yaw commands from the pilot and copilot rudder pedals to the rudder through a series of quadrants, cables, levers and pushrods. Movement of the rudder pedals is transmitted to two hydraulic Power Control Units (PCU). The PCU move the rudder in proportion to the amount of rudder pedal input. The rudder system also has inputs from the Automatic Flight Control System (AFCS) and the rudder trim actuator. The rudder system has the components that follow: • • • • • • • • • Rudder Pedals Rudder Forward Quadrants Rudder Mixer Quadrant Rudder Restrictor Rudder Aft Quadrant Power Control Unit/Actuator Rudder Shut-Off Valves PCU Input Bungee Rudder Position LVDT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 44 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER CONTROL SYSTEM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 45 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS This retained pressure supplies the rudder with gust dampening protection when the aircraft is parked. It also supplies flutter suppression in flight when there is no system hydraulic pressure available. A leak detect valve monitors for internal leakage in the rudder PCU. RUDDER SYSTEM SIMPLIFIED DESCRIPTION There are two pairs of mechanically linked rudder pedals located in the flight compartment, one pair for the pilot and one pair for the copilot. Directional control movements from either the pilot or copilot rudder pedals are transmitted simultaneously by two independent cable circuits to the mixer quadrant. The mixer quadrant is located below the cabin floor, aft of the turbine burst zone. From the mixer quadrant, a single cable circuit is routed aft and below the left side of the cabin floor. The cables pass through the pressure seals at the aft bulkhead, then up to the aft quadrant located behind the front spar of the vertical stabilizer. From the aft quadrant, a pushrod actuates two hydraulic Power Control Units (PCU) through an artificial feel spring unit. The two PCU are installed, one above the other, on the forward face of the vertical stabilizer rear spar and connected to the rudder control surface at the midpoint of the fore rudder. The No.2 system supplies hydraulic power to the upper PCU and the No.1 system supplies hydraulic power the lower PCU. A mechanical rudder input restrictor is attached to the right rudder forward quadrant. The restrictor is also connected to the flap select lever with pushrods. The restrictor limits rudder travel when the flaps are fully retracted. The restrictor limits fore rudder travel to 12° left and right of centre when 0° flap is selected. When 5° flap or greater is selected, full fore rudder travel of 18° left and right of centre is available. A hydraulic pressure limiting system reduces the pressure available to the rudder PCU as airspeed increases. Therefore, rudder authority is limited as a function of airspeed in order to reduce excessive yaw rate and structural loading of the aircraft. Airspeed data is obtained from the Air Data Units (ADU). The pressure limiting function is under the control of the Flight Control Electronic Unit (FCECU). A pressure compensator in the rudder PCU keeps 50 psi (344.7 kPa) pressure in the actuator when both hydraulic systems are inoperative. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 46 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER CONTROL SYSTEM SYNOPTIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 47 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER PEDALS PURPOSE The rudder pedals transmit inputs to the rudder control system and the main brake system. Each pair of rudder pedals is attached through a series of levers to its applicable rudder forward quadrant located below the flight compartment floor. Fore and aft movement of the rudder pedals rotates the rudder forward quadrant giving control of the rudder. The pilot and copilot rudder pedals are connected to each other through an interconnect rod. The rudder control system can be operated from either the pilot or the copilot position. The rudder pedals rotate about the pedal support tubes to supply foot brake control. A system of rods and levers transmits movement of the rudder pedals to the brake cable system. Two single cables from the pilot brake pedals operate the hydraulic brake control valves. A cable connecting the pilot and copilot brake pedals to each other allows for operation of the brake system from either the pilot or the copilot position. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 48 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER PEDALS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 49 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER PEDALS PURPOSE CONTINUED The pilot and copilot rudder pedals are pivot-mounted to brackets below the flight compartment floor. A rudder pedal adjustment handle allows fore and aft adjustment of either pair of rudder pedals to accommodate individual pilot preference for pedal difference. Each adjustment handle is located on the pedestal between the pilot feet. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 50 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER PEDAL ADJUSTMENT ASSEMBLY TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 51 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER FORWARD QUADRANTS PURPOSE The rudder forward quadrants transmit rudder pedal inputs to the rudder mixer quadrant. There are two rudder forward quadrants, one located below the pilot rudder pedals and the other located below the copilot rudder pedals. Each rudder forward quadrant is connected to its applicable pair of rudder pedals through a series of tubes and levers. The rudder forward quadrant transmits rudder cable control movement from the rudder pedals aft to the mixer quadrant. Each rudder forward quadrant is located below the flight compartment floor and is attached to the aircraft by two mounting brackets. The copilot rudder forward quadrant has a restrictor mechanism lever and two travel stops. This is part of the restrictor mechanism, which expands rudder travel in conjunction with flap deployment. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 52 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - CO-PILOT’S RUDDER FORWARD QUADRANT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 53 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER MIXER QUADRANT PURPOSE The rudder mixer quadrant combines rudder control from the two rudder forward quadrants and transmits it to the rudder aft quadrant. The rudder mixer quadrant is a three-pulley quadrant installed below the cabin floor, aft of the turbine rotor burst zone. It combines rudder control from the two rudder forward quadrants and transmits it to the rudder aft quadrant. The two pairs of control cables are routed aft from the rudder forward quadrants to the upper two pulleys of the mixer quadrant. This dual cable arrangement ensures continued rudder control if a single cable failure occurs between either the pilot or copilots rudder pedals and the mixer quadrant. From the lower pulley of the mixer quadrant, a single pair of cables is routed aft and below the left side of the cabin floor. The cables pass through the pressurization seal at the rear pressure dome in the aft fuselage, then up to the rudder aft quadrant in the vertical stabilizer. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 54 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER MIXER QUADRANT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 55 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER AFT QUADRANT PURPOSE The rudder aft quadrant transmits rudder control inputs from the mixer quadrant to the Power Control Units. The rudder aft quadrant is located halfway up the vertical stabilizer next to the Power Control Unit. It is the last quadrant in the rudder control system. The rudder aft quadrant has the primary travel stops for the rudder cable system. Rotation of the aft quadrant is opposed by two feel springs, which supply an artificial feel to the rudder pedals. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 56 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER AFT QUADRANT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 57 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER RESTRICTOR PURPOSE The rudder restrictor is designed to limit rudder travel when 0° flap is selected. The rudder restrictor is installed next to the copilot rudder forward quadrant below the flight compartment floor. Both the forward quadrant and the rudder restrictor are secured to the same support structure. The rudder restrictor is designed to limit the fore rudder to 12° right or left rudder travel when 0° flap is selected. If 5° or more flap is selected, then full fore rudder travel of 18° left and right of centre is restored. The flap selector lever is mechanically linked to the copilot rudder forward quadrant through a series of levers, connecting rods and a lay-shaft. At 0° degrees flap lever setting, the rudder restrictor plunger is fully engaged between the two travel stops on the copilot rudder pulley quadrant, permitting only partial rotation of the forward quadrant. At 5° of flap or more, the rudder restrictor plunger is withdrawn by means of levers, pushrods and a lay-shaft. This allows full rotation of the copilot rudder forward quadrant thus restoring full rudder travel. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 58 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER RESTRICTOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 59 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS The mechanically operated four-way Main Control Valve (MCV) positions the actuator ram. Position feedback is done by a mechanical linkage summing bar, which compares the commanded ram position with the actual position. Input from the pilot or AFCS causes the four-way MCV to reposition the ram towards the commanded position. Movement of the ram and the rudder stops when the actual ram position is the same as the commanded position nulled by the summing bar. RUDDER SYSTEM POWER CONTROL UNITS PURPOSE The PCU transmit rudder control inputs to the rudder surfaces. There are two Power Control Units (PCU), one located above the other in the vertical stabilizer. The PCU are attached directly to the mid-point of the fore rudder section of the rudder. The No.2 hydraulic system powers the upper PCU while the No.1 hydraulic system powers the lower PCU. Movement of the PCU causes the rudder to move and give directional control and stability to the aircraft. Each PCU is composed of two major assemblies: • • The compensator stores 50 psi in a spring loaded accumulator for use by the PCU in the event of loss of supply pressure to the PCU, maintaining flutter suppression. An attached mechanical level check window indicates the amount of fluid stored in the compensator. The upper and lower PCU compensators also perform gust damping when the PCU are depressurized. The leak detection valve detects unacceptable PCU internal leakage. The leak detection valve incorporates a 50 psi relief valve to prevent the PCU hydraulic fluid from escaping during a loss of supply pressure. The two anti-cavitation check valves prevent actuator cavitation. In the event one PCU is depressurized, the anti-cavitation valves crack at 2-8 psid to allow the serviceable PCU to overcome the failed unit. Actuator (ram) assembly with a fully balanced ram Integral hydraulic manifold assembly The integral hydraulic manifold assembly contains the following: • • • • • • • • • Pressure Port Inlet Check Valve Main Control Valve (MCV) Pressure Control Valve (PCV) Compensator Leak Detection Valve Anti-cavitation Check Valves (2) Pressure Reference Relief Valves (2) Pressure Transducers (2) The pressure port supplies system hydraulic pressure to the inlet check valve and then to the Pressure Control Valve (PCV). The PCV regulates the control pressure as a function of airspeed in order to reduce excessive yaw rate and structural loading of the aircraft. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 60 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER POWER CONTROL UNIT (PCU) TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 61 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS de-energizes the rudder shut off valve and sets the pressure control valve of the failed system to zero pressure. At the same time, the FCECU increases the pressure to the active PCU to compensate for the loss. The rudder control system continues to operate if one PCU fails at pressures of 1500 to 3000 psi. RUDDER SYSTEM POWER CONTROL UNITS If airspeed is invalid the rudder pressure will default to 700 psi. If flap position is valid and flaps extend beyond 5°, the pressure will default to 1225 psi. If both airspeed and flap position are invalid, the pressure will default to 1225 psi. PURPOSE CONTINUED The actuator return fluid from the failed PCU is then circulated through the MCV through the compensator to the other side of the actuator. Thus avoiding fluid escape form a failed PCU when driven from the serviceable PCU. The two pressure reference relief valves limit the PCU pressure to 3200 psid. Also, the pressure reference relief valves will crack at 2-8 psid in the event of a MCV jam with the PCU depressurized. Thus allowing a jammed PCU to bypass and be back-driven by the functioning PCU. The two pressure transducers supply PCV HML pressure feedback signals to the FCECU. The FCECU interfaces with the rudder PCU LVDT pressure sensors. The FCECU excites two LVDT pressure sensors in each PCU and processes their signals to obtain the pressure at the output of the rudder PCU pressure control valve. The FCECU left command and monitor path interface with the lower rudder PCU LVDT pressure sensors to provide loop closure and actuator monitoring. The FCECU right command and monitor path interface with the upper rudder PCU LVDT pressure sensors to provide loop closure and actuator monitoring. The monitoring consists of command comparison monitor 6.7% pressure difference >1.2 sec, overpressure monitor 8%>command pressure, under pressure monitor 8%<command pressure, and conflicting pressure status >6 sec. The hydraulic pressure supplied to the rudder PCU is limited as a function of airspeed in order to reduce excessive yaw rate and structural loading of the aircraft. This pressure limiting function is performed by the Flight Control Electronic Control Unit (FCECU) in conjunction with the Rudder Hinge Moment Limiter System (HML). Airspeed data is obtained from the Air Data Units (ADU). The Rudder Hinge Moment Limiter System (HML) is a part of each PCU. The HML has a rudder shut off valve, a pressure control valve and two pressure sensors for each PCU. The HML is interfaced with and controlled by the FCECU. During normal operation, the No.1 and No.2 hydraulic systems supply 3000 psi (20684 kPa) of pressure. The HML and FCECU reduce this pressure to 1500 psi (10342 kPa) at each PCU. As airspeed increases, the FCECU and the HML gradually reduce the pressure at each PCU down to a minimum pressure of 600 psi (4137 kPa). Limiting the hydraulic pressure available to the rudder PCU reduces total rudder travel at higher aircraft speeds. If either No.1 or No.2 hydraulic systems fails, the FCECU TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 62 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER PCU SCHEMATIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 63 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER SHUT OFF VALVES PURPOSE The Rudder Shut Off Valves (SOV) supply hydraulic system pressure to the rudder PCU. Each rudder PCU is equipped with a Rudder Shut Off Valve to shut down the PCU in the event of a rudder hinge moment limiter malfunction. The rudder SOV are located on the vertical stabilizer rear spar below the rudder PCU. The rudder SOV provide a redundant means to de-pressurize the PCU for other pressure regulation failures. Each FCECU channel controls its SOV open and close. The rudder SOV operate normally energized, porting 3000 psig supply pressure to the upper and lower rudder PCU. If a PCU pressure regulation failure is detected, the FCECU will command zero pressure to the PCU pressure control valve and command the associated rudder SOV to close. The rudder Push Off switch-light(s) also commands the FCECU to actuate the rudder SOV. In the de-energized condition, the rudder SOV de-pressurizes its PCU by porting return pressure to the PCU pressure port for flutter suppression. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 64 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER SHUT OFF VALVE (SOV) TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 65 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM PCU INPUT BUNGEE PURPOSE The PCU input bungees transmit rudder system control feel unit assembly inputs to the rudder PCU. There are two PCU input bungees, one for each rudder PCU. Each PCU input bungee has a spring strut and a motion detector. Each spring strut is installed between the feel unit assembly and its related PCU summing bar. A spring strut motion detector is installed parallel to each spring strut and has a cam arm, link, and limit switch. During normal operation, each spring strut length stays constant. Any rotation of the rudder aft quadrant by the pilot is directly transmitted through the spring strut to its related PCU. In the event of a jam of the PCU or its linkage, any further pilot input to the rudder aft quadrant causes an inner spring in the strut to either stretch or compress. This action either increases or decreases the overall length of the strut. The change in strut length causes the motion detector cam arm to trigger the limit micro-switch. When the limit micro-switch has been triggered, the applicable RUD 1 or RUD 2 rudder switch-light on the glare-shield panel comes on with the inscription, PUSH OFF, to warn of the jammed condition. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 66 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER PCU INPUT BUNGEE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 67 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER POSITION LVDT PURPOSE The rudder position Linear Variable Differential Transformer (LVDT) supplies an electrical signal, which is equivalent to the angular position of a flight control surface. A rudder position LVDT is located in the vertical stabilizer next to the rudder. It monitors the position of the rudder then transmits the rudder position data to the Flight Control Electronic Control Unit (FCECU). The FCECU rudder position LVDT also transmits the rudder position data (through the IFC) to the Powered Flight Control Surface Indicator (PFSCI) located on the pilot Multi-Functional Display (MFD) to display the position of the rudder and to the FDR. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 68 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER POSITION LVDT TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 69 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER POSITION LVDT CONTROLS AND INDICATIONS The rudder position LVDT also transmits the rudder position data to the Powered Flight Control Surface Indicator (PFSCI) located on the pilot Multi-Functional Display (MFD) to display the position of the rudder. A white rudder position indicator displays against a white scale. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 70 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - MULTI-FUNCTION DISPLAY/RUDDER POSITION TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 71 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER POSITION LVDT CONTROLS AND INDICATIONS When the PCU input bungee limit micro-switch has been triggered, the applicable RUD 1 or RUD 2 rudder switch-light on the glare-shield pane comes on with the inscription, PUSH OFF, to warn of the jammed condition. The switch-light can then be pushed to depressurize the jammed system. The illuminated inscription on the switch-light then changes to OFF to show the pilot that the switch has been pushed. The RUD 1 and RUD 2 POWERED FLIGHT CONTROL SHUTOFF (PFCS) switchlights are interfaces with the FCECU and are centrally located on the glare-shield. Pushing either RUD 1 or RUD 2 PUSH OFF switch-light cause the FCECU left or right channel to command zero regulated pressure to the appropriate rudder PCU and caption the switch-light to OFF. Pushing either RUD 1 or RUD 2 PUSH OFF switch-light will also cause the selected rudder system rudder shut off valve to close and bypass the rudder PCU load limit pressure reference relief valve for flutter suppression. The FCECU inhibits both PFCS switch-lights from being manually actuated OFF at the same time and captions both RUD 1 and RUD 2 switch-lights to PUSH. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 72 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER PUSH OFF SWITCH-LIGHTS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 73 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER POSITION LVDT CONTROLS AND INDICATIONS If hydraulic failure does occur, the related No.1 RUD HYD or No.2 RUD HYD caution light comes on. These caution lights also come on if the FCECU has shut down one of the hydraulic systems due to valve malfunction or if either RUD 1 or RUD 2 switchlight is pushed. The No.1 or No.2 RUD HYD caution light comes on for the following: • • No.1 or No.2 Hydraulic system pressure is <350 ± 50 psi (2413 ± 344.7 kPa) RUD Push Off switch is depressed or the shut-off valve is de-energized The RUD CNTRL caution light comes on for any of the following: • • • • • • • FCECU detects a difference of 17 knots or more between the Airspeed 1 and Airspeed 2 from the Air Data Units FCECU loses its ability to limit hydraulic pressure Both hydraulic systems fail If airspeed is invalid the rudder pressure will default to 700 psi/channel If both flap positions are valid and flaps >5 the pressure will default to 1225 psi/channel If airspeed and flap position are invalid the pressure will default to 1225 psi/ channel TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 74 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER CONTROL SYSTEM CAUTION LIGHTS TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 75 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER SOV HYDRAULIC SCHEMATIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 76 of 340 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 77 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER FEEL AND SUMMING PURPOSE The rudder feel and summing unit transmits rudder system artificial feel to the rudder pedals and biases the complete rudder system during rudder trimming or yaw damping. INTRODUCTION The rudder feel and summing unit gives artificial feel to the rudder pedals during operation. Because the rudder system is a powered flight control, the unit is used to prevent the pilot from over controlling the aircraft in flight. GENERAL DESCRIPTION The Rudder Feel and Summing Unit (RFSU) provides artificial feel to the rudder pedals. Rudder pedal feel is artificially produced by feel springs on the rudder feel and summing unit. The rudder feel and summing unit mechanically transmits rudder system commands to the rudder Power Control Units (PCU). The rudder feel and summing unit is biased by rudder pedal input, rudder actuator trim input and yaw damper actuator input. The rudder feel and summing system has the components that follow: • • • • • Trim Actuator Rudder Feel and Summing Unit Summing-Yaw Damper Actuator Rudder Trim Switch Rudder Trim Indicator TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 78 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER FEEL AND SUMMING SYSTEM BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 79 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER FEEL AND SUMMING SIMPLIFIED DESCRIPTION The Rudder Feel and Summing Unit (RFSU ) gives artificial feel to the rudder pedals. The unit is installed just behind the rudder aft quadrant, in series with the rudder control system. The trim actuator is attached to the vertical stabilizer at one end and to the RFSU at the other end. The trim actuator uses a brushless motor to extend or retract the actuator arm. The actuator output causes the rudder to move left or right, by summing the RFSU inputs and transmitting the force to the rudder PCU. Rudder trimming biases the complete rudder system, so that a newly trimmed position is sensed by the pilot as the neutral position. Movement of the rudder pedals extends one of the two feel springs in the RFSU. The force required to extend the springs gives artificial feel to the pilots, when operating the rudder pedals. The rudder pedal output causes the rudder to move left or right, by summing the RFSU inputs and transmitting the force to the rudder PCU. When the force on the pedals is removed, the feel spring contracts, and the pedals return to the trimmed neutral position. A rudder yaw damper actuator, supplies automatic compensation for minor rudder deflections to improve directional stability and turn co-ordination. The rudder yaw damper actuator output causes the rudder to move left or right, by summing the RFSU inputs and transmitting the force to the rudder PCU. Yaw damper authority is 4.5° of fore rudder movement either side of centre. The yaw damper gets its inputs from Flight Guidance Modules No.1 and No.2 and needs both inputs for operation. The yaw damper actuator works independently or in conjunction with the Automatic Flight Control System (AFCS). TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 80 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER FEEL AND SUMMING SYNOPTIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 81 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM RUDDER FEEL AND SUMMING SIMPLIFIED DESCRIPTION The rudder trim switch, located on the centre console, is used to extend or retract the rudder trim actuator. Turning the RUDDER trim switch fully to the left (L) or right (R), gives trim at a high rate. When the switch is turned to the first graduation line, a slower trim rate is given. The trim actuator can move the rudder surface a maximum of 10° to the left or right of centre. As the rudder is being trimmed the position is shown on the RUDDER trim indicator. Rudder trim indication is transmitted by the trim actuator integral Linear Variable Displacement Transformer (LVDT) that monitors the trim actuator position and shows it on the RUDDER trim indicator. The LVDT signal is also transmitted to the IFC Flight Data Recorder (FDR). If the LVDT fails, the trim actuator stays functional but no trim position is shown on the RUDDER trim indicator. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 82 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS - RUDDER TRIM SWITCH AND POSITION INDICATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 27 - FLIGHT CONTROLS Issue 6 - January 2023 Page 83 of 340 BOMBARDIER DHC 8-400 (PWC PW150) FLIGHT CONTROLS RUDDER SYSTEM TRIM ACTUATOR PURPOSE The trim actuator transmits linear movement to the rudder feel and summing unit to bias the rudder control system for yaw deviations. The trim actuator is attached to the mid-spar of the vertical stabilizer and connected at the rear to two trim arms that form part of the summing unit. The trim actuator has a DC motor which extends and retracts the actuator. The position of the trim actuator is monitored by an integral Linear Variable Differential Transformer (LVDT) and shown on the RUDDER trim indicator located in the flight compartment on the centre console. When the RUDDER trim switch in the flight compartment is selected fully to L, power is directed through a normally closed extend limit switch for rapid left trim, causes the trim actuator to extend. If the actuator exte