Flight Controls Description and Operation Table of Contents 1 INTRODUCTION .......................................................................................................................... 2 1. Flight Controls ............................................................................................................................... 2 2 PRINCIPLE OF TABS................................................................................................................... 4 1. 2. 3. 4. Trim tabs ....................................................................................................................................... 4 Balance tabs ................................................................................................................................. 4 Trim/balance tabs ......................................................................................................................... 4 Spring tabs .................................................................................................................................... 4 3 CABLE SYSTEMS ........................................................................................................................ 6 This is an Uncontrolled Copy. For Training purposes only All rights reserved. Disclosure to third parties of this document or any part thereof, or the use of any information contained therein for purposes other than provided for by this document, is not permitted, except with prior and express written permission by the Accountable Manager of the Aircraft Maintenance & Training School. Fokker 50/60: 27-01 Code 3001N/Issue 1 Page 1 1 INTRODUCTION 1. Flight Controls The flight controls described in this chapter are: - the primary flight controls, which are: - the elevators· - the ailerons - the rudder - the supplementary flight controls, which are: - the elevator trim tab - the aileron balance tab, spring tabs and trim/balance tab - the rudder balance tab and trim tab - the secondary flight controls, which are: - the flaps. The primary flight controls are operated by a combination of cables and push-pull rods, the supplementary flight controls by cables; the trim for the aileron, however, is electrically operated. The flaps are operated by a flap power drive unit which normally operates in the hydraulic mode but which also has an electric motor for alternate operation. The flight control lock system prevents damage to the flight controls by wind gusts. When operated, the flight controls are locked as follows: - the elevators down - the ailerons and rudder in neutral. It also limits the movements of the POWER levers. A stall warning system gives an alert in case the angle of attack is too high. The Fokker 50/60 has a take-off warning system which gives audible and visible alerts in case the flight controls are in unsafe positions before take-off. Fokker 50/60: 27-01 Code 3001N/Issue 1 Page 2 Location of Flight Controls RH Elevator Trim/Balance Tab Trim Tab Rudder Trim Tab RH Aileron Spring Tab Balance Tab LH Elevator RH Outer Flap RH Inner Flap LH Inner Flap LH Outer Flap LH Aileron Spring Tab Balance Tab Fokker 50/60: 27-01 Code 3001N/Issue 1 Page 3 2 PRINCIPLE OF TABS The Fokker 50/60 has the following tabs: - a trim tab on the right elevator - a balance tab and a spring tab on the left aileron - a trim/balance tab and a spring tab on the right aileron - a balance tab and a trim tab on the rudder. 1. Trim tabs These tabs are used to keep a certain aircraft attitude in flight. They give a means of eliminating unwanted control forces, normally necessary after a disturbance of the attitude. They are controlled from the flight compartment. 2. Balance tabs These tabs are used to keep the control forces within limits. They are connected to the aircraft structure and their deflection is proportional to the travel of the relevant flight control. 3. Trim/balance tabs This tab is used to keep a certain attitude and to keep the control forces within limits. 4. Spring tabs These tabs are used to decrease the control forces when the airload on the ailerons increases. Fokker 50/60: 27-01 Code 3001N/Issue 1 Page 4 Flight Control Tabs Trim Tab No Aerodynamic Load Aerodynamic Load Spring Tab Balance Tab Fokker 50/60: 27-01 Code 3001N/Issue 1 Trim/Balance Tab Page 5 3 CABLE SYSTEMS The primary flight controls use lock-clad cables. Lock-clad is a trade name for cables with an aluminum tubing swaged around them. The other flight controls use carbon steel cables. As a general rule the cables run from below the flight compartment floor along the electrical power center into the ceiling of the forward passenger compartment. From there they run through the partial pressure bulkhead to the center wing. The aileron cables run to the crosswheel behind the rear spar of the center wing and then along the rear spar of the center wing and outer wings to the aileron differential sectors. The cables of elevators and rudder go from the center wing through the dorsal fin to the rear fuselage (tail) and stop at tension regulators. The cables for the elevator trim tab run below passenger compartment floor to the rear fuselage. Because the screw jack is in the elevator itself, the cable run is through the right elevator's torque tube. The cables for the rudder trim tab run parallel to the rudder cables to the screw jack in the leading edge of the rudder. Cable connectors fore and aft of the partial pressure bulkhead are installed for quick replacement of worn cables. The tension of the cables is set by turnbuckles. The cables are supported by pulleys, fairleads and seals. The seals in the partial pressure bulkhead have each a silicon rubber seal between two metal cover plates. The assembly is attached to the bulkhead with bolts. The cable moves through pressure seal halves which are kept in position in the nipple of the seal. Cable System Pressure Seal Halves Structure Partial Pressure Bulkhead Lock-clad Cable Nipple Cable Connector Cover Plate Silicone Rubber Seal Cover Plate Fokker 50/60: 27-01 Code 3001N/Issue 1 Page 6 Elevators Description and Operation/Maintenance Information Table of Contents 1 ELEVATORS ................................................................................................................................ 2 1.1 1.2 1.3 Introduction ................................................................................................................................... 2 Mechanical System ....................................................................................................................... 2 Elevator Feel Control System ....................................................................................................... 6 • Introduction.............................................................................................................................. 6 • Modes of Operation................................................................................................................. 6 • Fault Indication ........................................................................................................................ 6 1.4 Maintenance Information – Configuration 1.................................................................................. 9 1.5 Maintenance Information – Configuration 2................................................................................ 11 1.6 Trim Tab Control System ............................................................................................................ 13 Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 1 1 ELEVATORS 1. Introduction Control columns control the elevators. There is an elevator connected through hinges to the left and right trailing edges of the horizontal stabilizer. The range of the elevator is 25° up and 22° down. A trim tab is connected through hinges to the trailing edge of the right elevator, inboard side. The range of the trim tab is 23° up and down. 2. Mechanical System The torque tube below the flight compartment floor connects the two control columns with each other. The two columns use ball bearings as pivot points. A horizontal rod connects a drive arm on the left end of the torque tube to a bellcrank which is attached with a bearing to the aileron intermediate torque tube. Two adjustable push-pull rods with an idler lever connect the bellcrank with an operating lever on the elevator intermediate torque tube. This torque tube is installed in the ceiling of the flight compartment entrance and is supported by two ball bearings on brackets. The drive sector, connected by bolts to the right end of the elevator intermediate torque tube, has two grooves for the dual two-way cable system, which runs to the cable tension regulator. The idler lever, operated by two adjustable push-pull rods, forms together with stop blocks the secondary stops. Behind Flight Compartment Operating Lever Intermediate Torque Tube Elevator (Dual) Cables Stop Bracket Aileron Cables Drive Sector Aileron Intermediate Torque Tube Bellcrank Horizontal Rod Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 2 Mechanical System Elevator Control Levers Actuator Cable Tension Regulator Bungees Control Columns Intermediate Torque Tube Vertical Linkage Torque Tube Bellcrank Horizontal Rod Flight-compartment Controls Control Column Head Control Column Control Wheel Scuff Plate Rigging Hole Hinge Point Stick Shaker Torque Tube Base Cover Guard Plate Drive Arm Base Aileron Cable Pulleys Horizontal Rod Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 3 The cable tension regulator system has two practically identical units; one unit for the elevators; one unit for the rudder. Both units are with bearings on a common tube. The cable tension regulator makes sure that a cable tension is maintained irrespective of temperature and structural movements. Each regulator has an upper and lower quadrant connected to a drive arm by hinges. There are compression springs between the frame on the drive arm assembly and the upper and lower quadrants. After the force is adjusted, any change in cable tension results in a swinging motion of the upper and lower quadrants about their axis. This increases or decreases the pull on the cables, necessary to maintain the cable tension. When a control force is applied, a brake assembly stops this regulating action between upper and lower quadrant. On the regulator is an indicator scales for rigging purposes. To each cable tension regulator unit are also attached: - stop blocks which limit the flight control travel (primary stops) - flight control lock tracks - quadrant for the cables from the servo of the autoflight control system (AFCS). To make the "feel" of the elevator control system better, a bungee is connected to the drive arm on the regulator. The other end of the bungee is connected to an actuator, which is electronically controlled. Drive rods connect the drive arm of the elevator cable tension regulator to the control levers of the left- and right elevators. Mechanical System in Tail Section Rudder Cable Tension Regulator Rudder Left Primary Stop Elevator Cable Tension Regulator Elevator Down Primary Stop Elevator Drive Rods Flight Control Lock Side Beam Rudder Drive Rod Stop Blocks Elevator and Rudder Stop Assembly AFCAS Cable Elevator Up Primary Stop Rudder Right Primary Stop Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 4 Cable Tension Regulators Elevator Cable Tension-Regulator Brake Assembly Compression Springs Rudder Cable Tension-Regulator Bungees Attachments Stop Block Elevator Drive Arm Support Tube Rudder Drive Arm Upper Quadrant Brake Assembly Barrel Forked Nut (Right Threaded) Spacer Friction Washers Rotating Bolt Forked Nut (Left Threaded) Lower Quadrant Compression Springs Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 5 3. Elevator Feel Control System • Introduction To make the control of the aircraft better, the tension in the bungees is controlled. As a result, the pilot does not feel the out-of-trim forces at the control column. The system has a single-channel modulated bungee control unit, an electrically operated bungee modulating actuator and a mechanical system. The position of both power levers and the flaps are inputs for the modulated bungee control unit. When the AUTO EL FEEL CTL pushswitch is, normal, the control unit gives a signal to the bungee modulating actuator. This actuator controls the tension of the springs in the bungees. A position sensor gives a feedback signal about the actual position of the actuator to the control unit. When the power to the actuator is stopped, the actuator keeps its last position. • Modes of Operation The system has three modes of operation: - the parking mode when the flight control lock is on - the taxiing mode when the flight control lock is off - the flight mode. In the parking mode the actuator is in the 25° position. This is also the rigging position. In the taxiing mode the actuator is between 7° and 21°. This depends on the position of the flaps only. In this mode the POWER levers are simulated in the take-off position to prevent the system to follow the various power selections during taxiing. In the flight mode the actuator is between 7° and 60°. This depends on the position of the POWER levers and flaps. • Fault Indication The system is continuously monitored through a test-circuit. If there is a fault in a power lever angle input or flap position input, a level 2 alert comes on 15 seconds after touch-down. During flight an action of the pilots is, in this case, not necessary. When there is an actuator or control unit related fault, the system stops; a level 2 alert comes on immediately. The AUTO EL FEEL CTL pushswitch must be pushed to off to keep the actuator in its last position. When the AUTO EL FEEL CTL FAULT light is on, use the red LED’s in the front panel of the control unit to isolate the faulty component and/or related wiring. There are red LED’s for: - power lever circuits (PLA 1 and PLA 2) - flap circuit (FLAP) - actuator circuit (BOX/ACT). When the AUTO EL FEEL CTL FAULT light is on and there are no red indications on the control unit, the control unit itself must be checked. Overhead Panel Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 6 Modes of Operation FLIGHT MODE TAXI MODE PARK MODE FLAPS UP 25° FLT CTL LOCK ON FLAPS >8° TOUCH-DOWN 7° - 21° FLAP PLA: <TO FLAPS UP 7° - 60° PLA + FLAP LIFTOFF 7° - 21° FLAP PLA: TO FLAPS >8° 25° TAXI MODE FLT CTL LOCK OFF PARK MODE 2736-001 Elevator Feel Control Principle Elevators From Flight Compartment Cable Tension Regulator Modulated Bungee Control Unit 0° – 75° LH & RH PLA Flap Position Flight Control Lock LH & RH Ground/Flight Bungee Modulating Actuator Park Mode 25° (rigging/dispatch position) Taxiing Mode 7° – 21° (Flap input) Flight Mode 7° – 60° (Flap + PLA input) Bungees Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 7 Elevator Feel Control - hookup 28V DC COMMON DCBUS AUTO EL FEEL CTL OFF L PLA FAULT IAU OFF LEVEL 2 ON RPLA BUNGEE CONTROL UNIT FLAP POSITION INDICATOR INH TAKE-OFF FAULT MTP EXTEND R GND OPER L GND OPER ON M PLA1 RETRACT PLA2 FLAP FEEDBACK BOX/ ACT GUSTLOCK BUNGEE MODULATING ACTUATOR 2700-017B Power-lever Position Transmitter POWER Levers Links Lever Selector Position Transmitters Lever Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 8 1.4 Maintenance Information – Configuration 1 When the ELEVATOR FEEL CONTROL TEST toggle switch on the maintenance and test panel is operated, the TIP (test in progress) magnetic indicator shows white for about 30 seconds. The test circuit in the control unit starts a test program and the actuator goes to approximately 26°. When there are no faults, the test is completed with the level 2 alert. The system is automatically reset. When the TIP (test-in-progress) magnetic indicator stays black and the level 2 alert stays off, the control unit must be removed for a bench test. If the system is unserviceable, the mechanical system can be fixed with a special tool at 25°. The elevator system is now safe for flight, however, there is limited center of gravity range (refer to MMEL). Maintenance and Test Panel (MTP) Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 9 Tail Section Flight Compartment entrance, left side Modulating Bungee Control-Unit (MBCU) Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 10 1.5 Maintenance Information – Configuration 2 The fault read-out of configuration 2 is with numbered LED’s. Elevator Feel Control – hookup (configuration 2) 28V DC COMMON DCBUS AUTO EL FEEL CTL OFF L PLA FAULT IAU OFF LEVEL 2 ON RPLA BUNGEE CONTROL UNIT FLAP POSITION INDICATOR INH TAKE-OFF FAULT MTP EXTEND R GND OPER L GND OPER ON GUSTLOCK M 8 4 2 1 RETRACT FEEDBACK 1 3 5 7 9 11 13 15 FAULT PROB. CAUS E WINDOW FEEDBACK PLA FLAP POS DEADBAND Δ BETA CURRENT DIRECTION MBCU ACT/MBCU POT/MBCU IND/MBCU MBCU/ACT MBCU/ACT MBCU/ACT MBCU BUNGEE MODULATING ACTUATOR 2700-018B Tasks Flight Compartment entrance, left side Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 11 • Modulated Bungee Control Unit fault monitoring Four LEDs on the MBCU give up to 8 different fault codes. The fault codes are shown on a placard. Each LED represents a value; you have to add up the values of the activated LEDs to find the fault code. E.g. LEDs 1 and 4 are on to indicate fault code 5, this means that one (or both) PLA inputs are unreliable. Faults related to PLA or flap input signals only give a fault light when the aircraft is on the ground and the faulty input defaults to a fixed value. Faults, which are related to the actuator movement, give a fault light in flight or on the ground. The LEDs reset 46 seconds after the start of a system test on the ground. Fault LED 8 Window 1 -Feedback 3 -PLA 5 -Flap Position 7 -Deadband 9 √ Δ Beta 11 √ Current 13 √ Direction 15 √ Park Fault None -“- -“: LED is off; “√”: LED is on 4 --√ √ --√ √ -- 2 -√ √ --√ -√ -- 1 -√ √ √ √ √ √ √ -- FAULT Light On Ground/In Flight On Ground/In Flight On Ground only On Ground only On Ground/In Flight On Ground/In Flight On Ground/In Flight On Ground/In Flight Only when Flt Ctl lock on Details Actuator stops Actuator stops Default: PLA 80º Default: Flaps 8º Actuator stops Actuator stops Actuator stops • Window monitor The purpose of this monitor is to prevent full stroke actuator runaways during flight. The monitor sets a window in which the actuator is allowed to move. A change in flap position shifts the window. The monitor trips when the actuator position moves outside the window. • PLA input channel monitor The PLA input channels get inputs from PLA potentiometers. Each input has it own monitor, which trips when the left or the right PLA input voltage is outside the expected range. • Flap-input channel monitor The flap input uses an input voltage from the flap indicator. The flap input channel monitor trips when the flap input voltage is outside the expected range. • Feedback A potentiometer inside the actuator gives a feedback signal to the MBCU. A monitor trips when the feedback input voltage is out of range; this indicates an open or a shorted feedback signal. • Deadband The position of the actuator is represented by the angle Beta (β). The actuator starts to move whenever the difference between the actuator position and the feedback signal Δβ>2°. When moving, the actuator stops when Δβ<0.5°. This is controlled by a deadband circuit, which switches between a 0.5° mode and a 2° mode whenever the actuator starts or stops. The deadband monitor trips when the deadband circuit does not return to the 2° mode within 23 seconds. • Δ Beta The Δ Beta monitor checks for incorrect follow-up from the actuator and actuator runaways. The monitor trips when Δβis outside the nominal zero range for more than 11.5 seconds. • Current This monitor trips when the actuator current becomes too high; this indicates a jammed actuator. Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 12 1.6 Trim Tab Control System Trim wheels on the pedestal control the trim tab, which is attached to the right elevator. Each wheel has its own shaft. Chains and sprockets connect the two wheels to a common shaft below the floor of the flight compartment. On this shaft is a drum for the cable to the drive mechanism in the right elevator. This mechanism has a cable drum which operates a screw jack through gears. Cable drum and screw jack drive-arm are on the elevator hinge line; so elevator movement does not disturb the trim drive mechanism. The drive-a.rm controls the trim tab through a drive rod. A stop mechanism limits the angular travel of the control wheel to about one turn from neutral in either nose up or nose down direction. A mechanical dial near each control wheel shows the amount of trim. The pitch trim servo of the autoflight control system (AFCS) is connected through a chain and sprockets to the common shaft below the floor of the flight compartment. Elevator Trim Tab Cable Drum Bracket Gear Screw Jack Drive Arm Drive Rods Elevator Trim Tab Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 13 Mechanical System Trim Tab Trim Tab Drive Mechanism Trim Wheel Mechanical System in Pedestal Trim Control and Indicator Mechanism Trim Wheel Chain Tensioning Device Layshaft Assembly AFCS Drive Sprocket Fokker 50/60: 27-02 Code 3001N/Issue 1 Page 14 Elevators Description and Operation/Maintenance Information Table of Contents 1 ELEVATORS ................................................................................................................................ 2 1. 2. 3. Introduction ................................................................................................................................... 2 Mechanical System ....................................................................................................................... 2 Longitudinal Stability Augmentation System (LSAS) .................................................................... 6 • Introduction.............................................................................................................................. 6 • System set up.......................................................................................................................... 6 Controls and indications................................................................................................................ 8 Monitoring ..................................................................................................................................... 8 Maintenance Information .............................................................................................................. 9 • Built-In-Test ............................................................................................................................. 9 • Dispatch with an inoperative system..................................................................................... 10 • Dispatch with a degraded system ......................................................................................... 10 Trim Tab Control System ............................................................................................................ 11 4. 5. 6. 7. Fokker 50/60: 27-02 Code 3002N/Issue 1 Page 1 1 ELEVATORS 1. Introduction Control columns control the elevators. There is an elevator connected through hinges to the left and right trailing edges of the horizontal stabilizer. The range of the elevator is 25° up and 22° down. A trim tab is connected through hinges to the trailing edge of the right elevator, inboard side. The range of the trim tab is 23° up and down. 2. Mechanical System The torque tube below the flight compartment floor connects the two control columns with each other. The two columns use ball bearings as pivot points. A horizontal rod connects a drive arm on the left end of the torque tube to a bellcrank which is attached with a bearing to the aileron intermediate torque tube. Two adjustable push-pull rods with an idler lever connect the bellcrank with an operating lever on the elevator intermediate torque tube. This torque tube is installed in the ceiling of the flight compartment entrance and is supported by two ball bearings on brackets. The drive sector, connected by bolts to the right end of the elevator intermediate torque tube, has two grooves for the dual two-way cable system, which runs to the cable tension regulator. The idler lever, operated by two adjustable push-pull rods, forms together with stop blocks the secondary stops. Behind Flight Compartment Operating Lever Intermediate Torque Tube Elevator (Dual) Cables Stop Bracket Aileron Cables Drive Sector Aileron Intermediate Torque Tube Bellcrank Horizontal Rod Fokker 50/60: 27-02 Code 3002N/Issue 1 Page 2 Mechanical System Elevator Control Levers Actuator Cable Tension Regulator Bungees Control Columns Intermediate Torque Tube Vertical Linkage Torque Tube Bellcrank Horizontal Rod Mechanical System in Flight Compartment Control Column Head Control Column Control Wheel Scuff Plate Rigging Hole Hinge Point Stick Shaker Torque Tube Base Cover Guard Plate Drive Arm Base Aileron Cable Pulleys Horizontal Rod Fokker 50/60: 27-02 Code 3002N/Issue 1 Page 3 The cable tension regulator system has two practically identical units; one unit for the elevators; one unit for the rudder. Both units are with bearings on a common tube. The cable tension regulator makes sure that a cable tension is maintained irrespective of temperature and structural movements. Each regulator has an upper and lower quadrant connected to a drive arm by hinges. There are compression springs between the frame on the drive arm assembly and the upper and lower quadrants. After the force is adjusted, any change in cable tension results in a swinging motion of the upper and lower quadrants about their axis. This increases or decreases the pull on the cables, necessary to maintain the cable tension. When a control force is applied, a brake assembly stops this regulating action between upper and lower quadrant. On the regulator is an indicator scales for rigging purposes. To each cable tension regulator unit are also attached: - stop blocks which limit the flight control travel (primary stops) - flight control lock tracks - quadrant for the cables from the servo of the autoflight control system (AFCS). To make the "feel" of the elevator control system better, a bungee is connected to the drive arm on the tension regulator via an actuator which is electronically controlled. Drive rods connect the drive arm of the elevator cable tension regulator to the control levers of the left- and right elevators. Mechanical System in Tail Section Rudder Cable Tension Regulator Elevator Cable Tension Regulator Rudder Left Primary Stop Elevator Down Primary Stop Elevator Drive Rods Flight Control Lock Side Beam Rudder Drive Rod Stop Blocks Elevator and Rudder Stop Assembly AFCAS Cable Elevator Up Primary Stop Rudder Right Primary Stop Fokker 50/60: 27-02 Code 3002N/Issue 1 Page 4 Cable Tension Regulator Bungee Actuator connection to Cable Tension Regulator Elevator Lever Elevator Lever Auto-pilot Quadrant Tension Regulator Elevator Drive Hub WL 935 Main Shaft Shaft Support Bracket Bungee Actuator Spring Bungee Bungee Actuator Attachment Spring Bungee Bungee Actuator Attachment A/P Servo Fokker 50/60: 27-02 Code 3002N/Issue 1 Page 5 3. Longitudinal Stability Augmentation System (LSAS) • Introduction To make the control of the aircraft better, the tension in the bungees is controlled. As a result, the pilot does not feel the out-of-trim-forces caused by engine power setting, flap position change and airspeed change. The system also damps possible pitch oscillation. • System set up The system has a single-channel Elevator Modulating Bungee Control Unit (EMBCU) and an electrically operated bungee actuator. The actuator is connected to the elevator cable tension regulator. When the system is in operation, the control unit gives a signal to the actuator. The actuator changes the actuating arm (angle) of the bungee spring on the elevator cable tension regulator. The system has three modes of operation: - the take off mode 13° - the en-route mode 13° - 52° - the landing mode 13° - 60°. The control unit uses the following information: - power lever angle (PLA)from engine electronic control units (EEC) - flap position from the flap position transducer - indicated airspeed (IAS)from air data computer 1 (ADC1) - angle off pitch (AP)from attitude and heading reference system 1 (AHRS 1) - ground/flight information from ground/flight relays - flight control lock position. At power up the system starts in the take off mode. After flap selection, flight control lock off, power levers in take-off, lift-off and flaps up, the system changes from take-off mode to the enroute mode. The system now uses power lever angle, flap position and indicated air speed information to position the actuator to the correct angle. In addition to this the angle of pitch information is used to damp possible pitch oscillation. During the descent the system changes from the en-route mode to the landing mode when the power levers are selected out of take-off and the flaps are selected. After touch-down and the flight control lock selected to "on", the system changes from the landing mode to take-off mode. Elevator Feel Control Principle Elevators From Flight Compartment Cable Tension Regulator 0° – 75° Modulated Bungee Control Unit Bungee Modulating Actuator LH & RH PLA Flap Position Flight Control Lock LH & RH Ground/Flight IAS (ADC) Pitch (AHRS) Take-off Mode 13° En-route Mode 13° – 52° Flight Mode 13° – 60° Bungees Fokker 50/60: 27-02 Code 3002N/Issue 1 Page 6 Elevator Feel Control OHP DEGRADED STAB AUG 28V DC DCBUS 1 IAU FAULT OFF LEVEL 2 OFF LEVEL 1 INH INH TAKE-OFF POWER SUPPLY POWER SUPPLY A B MONITOR B L EEC OK # REEC B MAIN FLAP POSITION B ON OK DISPATCH POSITION CONTROLLER # GUSTLOCK A POWERMODULE ADC ACTUATOR DRIVER AHRS GND L OPER DISPATCH POSITION DRIVER # FEED BACK SHUT-OFF M == GND R OPER 2737-003 ELEVATOR MODULATING BUNGEE CONTROL UNIT Fokker 50/60: 27-02 Code 3002N/Issue 1 ACTUATOR Page 7 4. Controls and indications The controls and indications of the system are on the general switching panel on the overhead panel. There are the following controls: - the STAB AUG pushswitch to switch of the system and to show the status of the system, normal (no lights), faulty (amber FAULT light on) or off (white OFF light on) - the DEGRADED light to alert the crew that the system is degraded in its function. 5. Monitoring The system is continuously monitored. When an actuator related fault is detected (runaway, incorrect positioning), a level 2 alert comes on immediately and the actuator stops in the last position. The STAB AUG pushswitch must be switched to OFF. When a power lever angle input or a flap position input fails, the level 2 alert comes on 15 seconds after touch-down. A flap position input failure also makes the DEGRADED light to come on. This DEGRADED light also comes on when the IAS, or angle of pitch input fails. 13° FLT CTL LOCK ON 13° - 60° PLA + FLAP TOUCH-DOWN 13° - 52° PLA + IAS + ANGLE OF PITCH + FLAP FLAPS >8° 13° PLA: <TO TAKE-OFF MODE FLAPS UP LANDING MODE PLA: TO EN-ROUTE MODE LIFT-OFF TAKE-OFF MODE FLT CTL LOCK OFF FLAPS >8° Modes of Operation 2737-002A Overhead Panel Fokker 50/60: 27-02 Code 3002N/Issue 1 Page 8 6. Maintenance Information • Built-In-Test Bite is available on the front panel of the control unit. Operate the SELECT button until the display shows TEST. Operate the ENTER button and the display is tested. When you release the ENTER button the test starts. The display shows BUSY. After 30 seconds the FAULT light and the DEGRADED light come on. Switch the STAB AUG pushswitch to OFF and normal again. The display shows PASS when the test was successful, and FAIL when a fault was detected. Push SELECT again and the display shows the "dashnumber" of the control unit. Push SELECT again and the display shows END. When a fault was detected, fault codes can de selected on the display for trouble shooting with the ENTER and SELECT buttons. BITE Instructions Menu’s Position Information Verification Test Start Display blank 15 minutes after last key strike Current Faults History Faults Memory Clear Fokker 50/60: 27-02 Code 3002N/Issue 1 ‘FD’: fault detected Page 9 • Dispatch with an inoperative system When the system is inoperative it can be fixed in a dispatch position. This can be done in two ways: 1. Operate the DISP POS button on the front panel of the control unit. The actuator will go to the dispatch position (25°). This is shown by a flashing LED. When the actuator is at 25°, the LED is on permanent. Now the STAB AUG pushswitch must be switched to OFF. 2. Remove the actuator and secure the mechanism in the dispatch position with a pin. This is also the rigging position. There is limited center of gravity range (refer to MMEL). • Dispatch with a degraded system The aircraft can be dispatched with a degraded system, however there is limited center of gravity range (refer to MMEL). Tail Section Actuator Fokker 50/60: 27-02 Code 3002N/Issue 1 Page 10 1.7 Trim Tab Control System Trim wheels on the pedestal control the trim tab, which is attached to the right elevator. Each wheel has its own shaft. Chains and sprockets connect the two wheels to a common shaft below the floor of the flight compartment. On this shaft is a drum for the cable to the drive mechanism in the right elevator. This mechanism has a cable drum which operates a screw jack through gears. Cable drum and screw jack drive-arm are on the elevator hinge line; so elevator movement does not disturb the trim drive mechanism. The drive-arm controls the trim tab through a drive rod. A stop mechanism limits the angular travel of the control wheel to about one turn from neutral in either nose up or nose down direction. A mechanical dial near each control wheel shows the amount of trim. The pitch trim servo of the autoflight control system (AFCS) is connected through a chain and sprockets to the common shaft below the floor of the flight compartment. Pedestal Elevator Position Indicator Elevator Trimwheel Fokker 50/60: 27-02 Code 3002N/Issue 1 Page 11 Elevator Trim – Mechanical System Trim Tab Trim Tab Drive Mechanism Trim Wheel Mechanical System in Pedestal Trim Control and Indicator Mechanism Trim Wheel Chain Tensioning Device Layshaft Assembly AFCS Drive Sprocket Fokker 50/60: 27-02 Code 3002N/Issue 1 Page 12 Ailerons Description and Operation/Maintenance Information Table of Contents 1 AILERONS .................................................................................................................................... 2 1. 2. 3. Introduction ................................................................................................................................... 2 Mechanical System ....................................................................................................................... 2 Trim/Balance Tab Control System ................................................................................................ 8 Fokker 50/60: 27-03 Code 3001N/Issue 1 Page 1 1 AILERONS 1. Introduction Two control wheels, one on top of each control column, control the ailerons. There is an aileron connected through hinges to the trailing edge of each outer wing, outboard side. The ailerons extend from the outer flap, outboard side, to the wing tips. The range of the ailerons is 33° up and 22° down. A spring tab is connected through hinges to the trailing edge of each aileron, inboard side. The range of these spring tabs is 13° up and down. A balance tab is connected through hinges to the trailing edge of the left aileron, outboard side. A trim/balance tab is connected through hinges to the trailing edge of the right aileron, outboard side. The range of this tab is 16° up and down. 2. Mechanical System Each control wheel drives through a single gear a cable drum in the head of the column. Secondary stops limit control wheel movement. A two-way cable system runs from each drum through the control column, around pulleys, under the flight compartment floor, rearwards to quadrants on the aileron intermediate torque tube. This torque tube provides synchronization of the control wheels. Head of Control Column Column Head Shaft Stop Block Hub Cap Retaining Nut Control Wheel Control Column Fokker 50/60: 27-03 Code 3001N/Issue 1 Page 2 Mechanical System Aileron Crosswheel Differential Sector Aileron Control Wheel Intermediate Torque Tube Control Column Head Control Column Control Wheel Scuff Plate Rigging Hole Hinge Point Stick Shaker Torque Tube Base Cover Guard Plate Drive Arm Base Aileron Cable Pulleys Horizontal Rod Fokker 50/60: 27-03 Code 3001N/Issue 1 Page 3 The aileron intermediate torque tube has: - four small cable quadrants for the cables from the control wheels - a large drive sector for the cable system to the aileron crosswheel - an elevator bellcrank. The large drive sector forms an integral part with the two smaller cable quadrants on the left. All quadrants are attached to the torque tube with bolts. The elevator bellcrank is on the left end of the torque tube. It rotates freely about the torque tube through a ball bearing. A cable system connects the large drive sector to the aileron crosswheel on the rear spar of the center wing. The aileron intermediate torque tube is accessible through a detachable floor panel in the flight compartment entrance. Below Flight Compartment entrance Drive Sector To Intermediate Torque Tube Aileron Intermediate Torque Tube Bulkhead Left Outer Quadrant Left Inner Quadrant Elevator Bellcrank Horizontal Rod Right Inner Quadrant Right Outer Quadrant Fokker 50/60: 27-03 Code 3001N/Issue 1 Page 4 Behind Flight Compartment Operating Lever Intermediate Torque Tube Elevator (Dual) Cables Stop Bracket Aileron Cables Drive Sector Aileron Intermediate Torque Tube Bellcrank Horizontal Rod Fokker 50/60: 27-03 Code 3001N/Issue 1 Page 5 The cast aileron crosswheel has three grooves; one for the cable system from the aileron intermediate torque tube; two for the cable systems to the differential sectors on the rear spar of the outer wings near the inboard end of each aileron. To the crosswheel are attached: - a quadrant for the cable from the servo of the autoflight control system (AFCS) - a lockplate with a hole for the flight control lock. The aileron crosswheel is accessible through a door on the left side of the center wing, provided the flaps are down. Each differential sector transfers the movement of the aileron cables to the spring tab balance unit on the aileron through a push-pull rod. Because of the angular attachment of this rod in relation to the center point of the sector, its linear travel in one direction is greater than in the other direction. This causes a greater "up" deflection of the aileron than a "down" deflection. This arrangement is necessary because an equal deflection results in an increase of drag on the wing with the "down" aileron (high wing) which causes a force on the aircraft into the wrong direction. Each differential sector is accessible through an access panel in the underside of the outer wing. The spring tab unit is attached to the front spar of the aileron. Each spring tab balance unit has: - a balance lever - a support shaft - a torsion bar - a housing. - a control lock. Push-pull rods connect the balance lever to the differential sector and drive rods to the spring tabs. The balance lever is attached to the hollow support shaft which rotates in ball bearings in the housing. The housing itself is attached to the aileron structure with bolts. Inside the support shaft is the torsion bar which is connected with tapered pins to the balance lever on one end and to the housing on the other end. Without airload, the torsion bar holds the balance lever in the center position and the aileron is aligned with the spring tab. With airload, the control force necessary to move the aileron causes the torsion bar to twist. This causes the spring tab to deflect with respect to the aileron surface which gives an aerodynamic boost. This boost decreases the control force necessary to move the aileron. The spring tab deflection is proportional to the airload on the aileron. The deflection is, however, limited by a stop pin at the fork end of the balance lever. Rollers on a bracket can lock each balance lever when the bracket is turned in the horizontal position. This prevents the spring tabs to move their aileron because of wind gusts. This spring tab control lock is cable operated to lock and is springloaded to unlock. The aileron travel is limited by two adjustable primary stops on the wing trailing edge. Principle of Differential Aileron Up Aileron Fokker 50/60: 27-03 Code 3001N/Issue 1 Down Aileron Page 6 Aileron From Flight Compartment Lock Plate Control Lock To left Differential Sector Crosswheel AFCAS Quadrant Cable Guard From AFCAS Servo Balance Unit B Aileron Stop A Bracket Differential Sector Aileron Torsion Bar Spring Tab Balance Lever Aileron End Rib ‘Down’ Stop Bolt Support Shaft Stop Arm Housing ‘UP’ Stop Bolt View B View A Fokker 50/60: 27-03 Code 3001N/Issue 1 Stop Pin Control Lock Page 7 Trim/Balance Tab Control System The double aileron-trim toggle-switch on the pedestal controls the trim/balance tab through an electrically operated actuator on the rear spar of the right outer wing. The actuator moves the tab through a drive arm, push-pull rods, idler levers and drive rods. The idler levers are on one end attached to the aileron main hinge bracket through pivots for balancing. A trim indicator near the toggle switches shows the trim position. A potentiometer in the actuator controls this indicator. NOTE: Without electrical power the indicator is in the full left position. Aileron Trim/Balance Tab Rear Spar Motor Actuator Grease Nipple Double Fork-end Grease Nipple Screwjack Drive Arm Push-pull Rods Rigging Pin Hole Idle Levers Main Hinge Bracket Drive Rods RH Aileron Trim/Balance Tab Fokker 50/60: 27-03 Code 3001N/Issue 1 Page 8 Aileron Trim Control 28V DC COMMON DC BUS AILERON TRIM PANEL DOWN UP RIGHT WING AILERON POSITION INDICATOR UP DOWN DOWN M == UP AILERON TRIM DRIVE UNIT 2714-001 Pedestal RUDDER Trim Knob Aileron Trim Position Indicator AILERON Trim Switch FLIGHT CONTROL LOCK Lever Fokker 50/60: 27-03 Code 3001N/Issue 1 Page 9 Pedestal Aileron Trim Switch Aileron Trim Indicator Aileron and Spring Tab Down Stop Spring Balance Unit Aileron 33 Spring Tab 13 13 Differential Sector Up Stop Fokker 50/60: 27-03 Code 3001N/Issue 1 Spring Tab Stop 22 Page 10 Rudder Description and Operation/Maintenance Information Table of Contents 1 RUDDER....................................................................................................................................... 2 1.1 1.2 1.3 Introduction ................................................................................................................................... 2 Mechanical System ....................................................................................................................... 2 Trim Tab Control System .............................................................................................................. 4 Fokker 50/60: 27-04 Code 3001N/Issue 1 Page 1 1 RUDDER 1. Introduction Rudder pedals, one set for each pilot, control the rudder. The rudder is connected through hinges to the trailing edge of the vertical stabilizer. It extends over the full span of the vertical stabilizer and has a horn balance. The range of the rudder is 20° to the right and left. A balance tab is connected through hinges to the trailing edge of the rudder; bottom side. The range of this balance tab is 3°. A trim tab is connected through hinges to the trailing edge; top side. The range of the trim tab is 17° to the right and left. 2. Mechanical System Support tubes below the main instrument panel, one on each side of the pedestal carry the rudder pedals. Each support tube is attached to brackets on the pedestal and side wall of the flight compartment. Adjustable push-pull rods connect quadrant levers, one on each rudderpedal adjustment-mechanism to quadrant levers on the rudder intermediate torque tube. This torque tube is below the flight compartment floor. A cable connects a large drive section the intermediate torque tube to the cable tension regulator in the rear fuselage. A drive rod connects the regulator to the control lever of the rudder. Mechanical System Rudder Cable Tension Regulator Rudder Pedals Rudder Intermediate Torque Tube Fokker 50/60: 27-04 Code 3001N/Issue 1 Page 2 The balance tab is controlled by an adjustable push-pull rod, connected to the short arm of an Lshaped balance lever. The forward end of this lever is attached to a lug on the vertical stabilizer structure. The rear end is mounted through a pivot to a bracket on the rudder main spar. This point is on the rudder hinge line, so movement of the rudder does not affect the position of the lever but causes the rod to move the tab in opposite direction. This reduces the control force necessary to operate the rudder. Secondary stop on the drive sector limits the rudder pedal travel. A scuff plate on the floor prevents damage of the floor panels. The rudder pedals are adjustable in a fore and aft direction with a crank between the pedals. A brake pedal is mounted in bearings on the fore end of each rudder pedal. The arrangement is such that movement of the rudder pedals does not affect the brake system. Mechanical System in Flight Compartment Side Wall Bracket Pedal Lever Support Tube Crank Pedestal Drive Shaft Rudder Pedal Brake Pedal Scuff Plate Push-pull Rod Rudder Intermediate Torque Tube Cast Frame Drive Sector Stop Bolt Toothed Quadrant Lever Worm Wheel Stop Pin Torque Tube Support Bracket Fokker 50/60: 27-04 Code 3001N/Issue 1 Page 3 1.3 Trim Tab Control System The drive mechanism of the rudder trim tab is between the two rudder ribs. This mechanism has a drum which operates a screw jack through gears. The screw jack moves the trim tab through a drive arm and drive rod. Cable, cable drum and screw jack drive-arm are on the rudder hinge line; so rudder movement does not disturb the trim drive mechanism. A pointer on the pedestal near the trim knob shows the amount of trim. Mechanical System in Tail Section Trim Tab Screw Jack Trim Tab Cable Drum Lug on Vertical Stabilizer Balance Lever Bracket Balance Tab Rudder Hinge Line Fokker 50/60: 27-04 Code 3001N/Issue 1 Rudder Page 4 Rudder Trim –mechanical system Trim Tab Drive Mechanism Trim Tab Balance Tab Trim Control Rudder Trim Knob Trim Knob Indicator Dial Torque Shaft Bearing Plate Distance Tube Drum Housing Drum Shaft Cable Drum Fokker 50/60: 27-04 Code 3001N/Issue 1 Page 5 Vertical Stabilizer Trim Tab Balance Tab Fokker 50/60: 27-04 Code 3001N/Issue 1 Page 6 Flight Control Lock Description and Operation Table of Contents 1 FLIGHT CONTROL LOCK............................................................................................................ 2 1. 2. Introduction ................................................................................................................................... 2 Mechanical System ....................................................................................................................... 4 Fokker 50/60: 27-05 Code 3001N/Issue 1 Page 1 1 FLIGHT CONTROL LOCK 1.1 Introduction A lever in the rear of the pedestal, left side, controls the flight control lock system through cables. The cables run to the center wing where they divide. One set runs to the aileron control lock pulley behind the rear spar of the center wing and to the aileron spring tab control-locks; the other set runs through the dorsal fin to the common pulley of the elevators and rudder control lock units near the cable tension regulators in the rear fuselage. The aileron control lock pin engages in a hole of a locking plate of the aileron crosswheel; the aileron spring-tab control lock holds the balance lever in the neutral position; the pins of the elevator and rudder control locks engage in holes of the lock tracks on the cable tension regulators. The flight control lock lever is mechanically connected to the power-lever locking-device in the pedestal. When on, the system also limits the movements of the POWER lever to prevent takeoff power selections with the flight controls locked. A cam on the drive pulley under the pedestal operates switches for the take-off warning system but also for the flight data recorder and cockpit voice recorder. Mechanical System Aileron Spring Tab Control Lock Elevator and Rudder Control Lock Aileron Control Lock Power Lever Lock Mechanism Fokker 50/60: 27-05 Code 3001N/Issue 1 Flight Control Lock Lever with Microswitch Page 2 Pedestal RUDDER Trim Knob Aileron Trim Position Indicator AILERON Trim Switch FLIGHT CONTROL LOCK Lever FLIGHT CONTROL LOCK Lever Thumb Lock Fokker 50/60: 27-05 Code 3001N/Issue 1 Page 3 1.2 Mechanical System The control locks of the aileron crosswheel, elevator and rudder are similar. Each lock has two springs. When the flight control lock lever is moved to the ON position and the flight controls are not in the correct position for locking, the locking pin compresses the locking spring. When the flight controls move to the correct position, the locking pin engages the lock plate. When a flight control lock cable breaks, the retract spring makes sure that the locking pin is pulled out of the lock plate. Flight Control Lock - Aileron Pinion Gear Shaft Housing Cable Guard Retainer Retract Spring Tapered Pin Aileron Crosswheel Flanged Bushing Lock Pin Locking Plate Drive Pulley Safety Spring Fokker 50/60: 27-05 Code 3001N/Issue 1 Page 4 Flight Control Lock – Elevator and Rudder Longitudinal Side Beam Cable Guard Pin Retainer Track of Tension Regulator Rudder Control Lock Locking Pin Elevator Control Lock Torque Tube Drive Pulley Aileron Balance Unit Flight Control Lock Fokker 50/60: 27-05 Code 3001N/Issue 1 Page 5 Pedestal FLIGHT CONTROL LOCK Lever Fokker 50/60: 27-05 Code 3001N/Issue 1 Page 6 Flaps Description and Operation/Maintenance Information Table of Contents 1 FLAPS........................................................................................................................................... 2 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Introduction ................................................................................................................................... 2 Mechanical System ....................................................................................................................... 4 Hydraulic Operation ...................................................................................................................... 8 Electrical Operation..................................................................................................................... 10 Flap Position Indication............................................................................................................... 12 Flap Failure Indication................................................................................................................. 12 Flap Asymmetry Protection......................................................................................................... 14 2 MAINTENANCE INFORMATION ............................................................................................... 16 2.1 2.2 2.3 2.4 Inspection and Servicing............................................................................................................. 16 Flap Asymmetry Test .................................................................................................................. 17 Flap Position Control-Unit Test................................................................................................... 18 Maintenance Intervals................................................................................................................. 19 3 LOCATION OF COMPONENTS................................................................................................. 20 Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 1 1 FLAPS 1.1 Introduction Each wing has an outer and inner flap. Rollers on the end ribs of these flaps are connected to tracks on the trailing edges of the outer wing and center wing. Rotating spindles along the end ribs and drive nuts connected to the end ribs move the flaps up or down. A flap power drive unit in the left nacelle controls the spindles through gearboxes and torque shafts. The flap power drive unit has a hydraulic motor and an electric motor. The flaps operate normally on hydraulic power. The travel of the outer flaps is from UP to 35 (up to down) with fixed preset positions at: UP 5, 10, 15, 20, 25 and 35. These positions are selected with the flap selector in the flight compartment. The travel of the inner flaps is only 2/3 of the outer flaps. Alternate flap operation is with the DC electric motor. The travel range is the same as in the hydraulic mode; however, any selection is possible. The DC electric motor is controlled by a switch on the pedestal. In the hydraulic mode, the travel time of the flaps from full up to full down is 20 seconds; this is 100 seconds in the electrical mode. Flap Control in Pedestal Flap Selector Alternate Flap Control Switch Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 2 Location of Components Intermediate Gearbox Flap Selector Outer Flap Support Hinge Visual Flap Position Indication Main Torque Shaft Spindle Gearbox Inner Flap Flap Power Drive Unit with Main Gearbox Flap Spindle with - Mechanical Stops - Limit Switches Flaps – left wing Outer Flap Surface Inner Flap Surface Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 3 1.2 Mechanical System In the hydraulic mode the flap selector on the pedestal is used to control the flap position. When the flap selector is moved from one to another position, a single closed-loop cable system is operated. This cable system runs from a cable quadrant in the pedestal (left side!) along the cables of the other flight controls to the center wing front spar. From this front spar the cable system runs through the leading edge to the left nacelle, through the accessory bay to the input pulley on the flap power drive unit in the ceiling of the left main gear bay. Flap Power Drive-unit with Main Gearbox Flap Power Drive Unit Flap Position Transmitters Input Pulley Filler Plug Drain Plug Drive Rods Fokker 50/60: 27-07 Code 3001N/Issue 1 Level Sightglass Main Gearbox Electric Motor Page 4 Flap Selector in Pedestal Flap Selector Detent Positions in Pedestal Rigging Pin Hole Control Rod Cross Shaft Control Rod Main Output Shaft Assembly Cable Quadrant Hub Cable Quadrant Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 5 Rollers on the end ribs of the flaps, tracks on the trailing edge of the outer wings and center wing support the flaps. Each outer flap has an additional support from a hinge in the middle of that section. The flap power drive unit with hydraulic and electric motors controls the main gearbox; the main gearbox drives through drive shafts the gearboxes of the spindles of the left outer and inner flaps. The inboard gearbox of the left inner flap drives through a drive shaft the inboard gearbox of the right inner flap. This latter gearbox drives an intermediate gearbox in the right main gear bay (ceiling). This gearbox in turn drives the three remaining gearboxes of the flaps on the right wing. Each drive shaft is a light alloy torque tube, which makes sure that sudden stops do not damage the gearboxes and support bearings. There are mechanical stops on the outboard spindle of the left inner flap. They stop the flaps in case of overtravel. There are two switches along the outboard spindle of the left inner flap. These switches are operated by an adjustable stop on the associated nut drive. They stop the electric motor in the full up and down positions when the flaps operate in the electrical mode. Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 6 Left Main Wheel Bay Position Transmitters Flap Power Drive Unit with Main Gearbox Flap System Cable Run from Fl-dk Cable Separation Detector Spindle Gearbox Flap Power Drive-Unit Main Gearbox Intermediate Gearbox P * Asymmetry Transducer operated by Support Hinge Fokker 50/60: 27-07 Code 3001N/Issue 1 Mechanical Stops Limit Switches Inner Flap Outer Flap Flap Power Drive Unit with - Hydraulic and Electric Motor - Selector Valve - Transmitters - Feedback Page 7 1.3 Hydraulic Operation In the hydraulic mode the flap selector in the flight compartment controls the flap selections. When a selection is made, the flap selector controls a input pulley on the flap power drive unit through a cable system. This pulley operates a single planetary gear which in turn moves through a gear wheel the actuating arm of a selector valve. This causes hydraulic pressure to drive the hydraulic motor, the main gearbox and flaps. When the flaps move, the feedback in the flap power drive unit rotates the single planetary gear which causes the selector valve to move back to neutral, then the flaps stop. In the hydraulic mode electrical power is needed to open the shut-off valve. Flap Hydraulic Operation 3000 psi Shut Off FPCU Flap Power Drive Unit Electrical Control Selector Flap Selector Input Feed Back Cable Separation Detector Main Gearbox Fokker 50/60: 27-07 Code 3001N/Issue 1 Transmitters Page 8 Another transmitter in the flap power drive-unit sends flap position information to the flap position control unit. This unit supplies flap information to external systems. A transmitter controlled by the flap selector sends position information to the control unit. The unit supplies flap selector position information to external systems. This information is not available when the flaps operate in the electrical mode. Flap selector discretes (ground applied) - 0° - 6.5° AFCS (ATA 22) - 0° - 14° AFCS - 0° - 22° AFCS - 0° - 33° AFCS - 33° - 35° ISU (ATA 34). Flap position discretes (ground applied) - 0° - 2° AFCS - 0° - 20 IAU (TO warning) (ATA 27) - 22° - 35° IAU (TO warning) (ATA 27) - 0° - 22° GPWS (ATA 34) - 22° - 35° IAU (LG warning) (ATA 32) - 28° - 35° IAU (LG warning) (ATA 32). Flap Power Drive-Unit – Position Transmitters Flap Position Transmitters Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 9 4. Electrical Operation In the electrical mode, the ALTERNATE FLAP CONTROL toggle switch controls the electric motor. This switch must first be pulled before UP or DOWN can be selected. When operated, first the latched-type alternate control relay changes position. This causes: - the shut-off valve to close the hydraulic pressure supply to the selector valve in the flap power drive unit - DC electrical power for the electric motor through contacts of the electric motor relay. Limit switches, operated by the nut on the outboard spindle of the left inner flap, de-energize the electric motor relay when the flaps are in the full up or full down position. Once they operate in the electrical mode, the flaps cannot operate in the hydraulic mode. To get back in the hydraulic mode the latched-type alternate control relay must change position. This occurs when: - the aircraft is on the ground, and - the flap selector is operated. When the flap selector is operated, a flap-selector operation-detector in the flap position control unit supplies a ground signal for the relay. Left Nacelle Limit Switches DoF Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 10 Normal and Alternate Flap Control SHUT-OFF 28V DC COMMON DCBUS RESET GND FLT SELECTOR OPERATED ALTERNATEFLAP CONTROL FLAP POSITION CONTROLUNIT HYDRAULIC ALTERNATE PEDESTAL ALTERNATE FLAP CONTROL UP DOW N LIMIT UP LIMIT ELECTRIC MOTO R DOWN UP DOWN SHUT-OFF VALVE BRAKE FLAP POWER DRIVE UNIT Fokker 50/60: 27-07 Code 3001N/Issue 1 ENERGIZED OPEN M DOWN UP 2754-002A Page 11 5. Flap Position Indication A flap position indicator shows the flap position. The indicator receives position information from a transmitter in the flap power drive-unit. 6. Flap Failure Indication An amber FLAP light on the central annunciator panel (CAP) comes on in any of the following situations: - there is in the hydraulic mode a discrepancy between flap selector position and actual flap position for more than a predetermined time - the cable between the flap selector and pulley on the flap power drive unit breaks. A failed cable detector senses this. The detector is in the pedestal. The predetermined time is 2 seconds necessary to examine if the flaps move and 20 seconds to examine if the flaps are on the selected position. Flap Position Indication 28VDC EMERDCBUS2 FLAP POSITION INDICATOR EL FEEL CTL LSAS FLIGHT DATA ACQUISITION UNIT MODULATED BUNGEE CONTROLUNIT TRANSMITTERS FLAP POSITION CONTROLUNIT FLAPPOSTION FLAPPOWER DRIVEUNIT Fokker 50/60: 27-07 Code 3001N/Issue 1 2756-001 Page 12 Flap Position Control Unit (FPCU) 28V DC EMERDCBUS2 POWER SUPPLY L FLAP POSITION TEST RFLAP POSITION IAU: FLAP ASYM ASYMMETRY >Δ2.5° COMPARATOR Δ4° SHUT-OFF TEST MTP SHUT-OFFVALVE FLAP ASYM TEST1 RESET TEST2 TEST CABLEDISCONNECT CABLEDISCONNECT DISCONNECT IAU: FLAP RESET SEPARATIONDETECTOR SELOPERATED DISCRETES FLAP SELECTOR POSITION FLAP POSITION SELECTOR POSITION TEST 14° DISAGREE SEL≠ FLAP T>2s & T> 20s TEST 16.5° FLAP POSITION DISCRETES TEST 2754-004 DISAGREE INH TEST ALTERNATE MODE ALTERNATE MODE RESET FLAP POSITION CONTROLUNIT Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 13 1.7 Flap Asymmetry Protection Flap asymmetry is not allowed. Therefore the left and right outer flap positions are continuously compared in the flap position control unit. Two position transducers, one controlled by each outer wing, send position information to the control unit. When the difference between the left and right outer flaps is more than 2.5°, the asymmetry comparator in the control unit energizes the shut-off coil of a latched-type relay in the control unit. This causes the shut-off valve in the flap power drive unit to close off the hydraulic pressure and therefore the flaps stop. The FLAP ASYM light on the central annunciator panel (CAP) comes on. NOTE: When the flaps operate in the electrical mode, they continue in case of an asymmetry. Reset of the protection occurs when the FLAP ASYM toggle switch on the maintenance and test panel is operated. Right Wing Flap Asymmetry Transducer DoF Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 14 Flap Control CAP FLAP ASYM BU FLAP N N BU IAU LEVEL 2 28V DC EMER DC BUS 2 LEVEL 2 INH INH TAKE-OFF POWER SUPPLY L FLAP POSITION TEST R FLAP POSITION ASYMMETRY >Δ 2.5° COMPARATOR Δ 4° SHUT-OFF TEST MTP TEST 1 FLAP ASYM RESET TEST 2 TEST 28V DC COMMONDC BUS CABLE DISCONNECT CABLE DISCONNECT DISCONNECT SEPARATION DETECTOR FLAP SELECTOR POSITION FLAP POSITION GND SEL OPERATED DISCRETES FLT SELECTOR POSITION TEST 14° ALTERNATE FLAP CONTROL DISAGREE SEL ≠ FLAP T>2s& T> 20s TEST 16.5° ALTERNATE PEDESTAL ALTERNATE FLAP CONTROL UP FLAP POSITION DISCRETES HYDRAULIC DISAGREE INH DOWN LIMIT UP LIMIT TEST DOWN ALTERNATE MODE TEST ELECTRIC MOTOR RESET UP FLAP POSITIONCONTROL UNIT DOWN SHUT-OFF VALVE BRAKE FLAP POWER DRIVE UNIT Fokker 50/60: 27-07 Code 3001N/Issue 1 ENERGIZED OPEN M DOWN UP Page 15 2754-001C 2 MAINTENANCE INFORMATION 1. Inspection and Servicing The fluid in the manifold of the flap power drive unit is in accordance with MIL-L-23699C. The fluid in the main, intermediate and spindle gearboxes is in accordance with MIL-L-6085A. The main gearbox has filler and level plugs, the intermediate and spindle gearboxes have each filler, level and drain plugs. Fluid in the seal drain and overflow tank can come from: - the electric pump (fluid: MIL-H-5606E), - the flap power drive unit (fluid: MIL-L-23699C). The pressure regulator of the hydraulic reservoir (fluid: MIL-H-5606E). Tail cone, left nacelle Seal Drain and Overflow Tank Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 16 2.2 Flap Asymmetry Test With the FLAP ASYM toggle switch on the maintenance and test panel you can examine the asymmetry protection. When operated to TEST 1, an asymmetry is simulated and therefore the flaps, provided in the hydraulic mode, stop and the FLAP ASYM light on the central annunciator panel is on. This situation is reset to normal when the FLAP ASYM toggle switch is operated to TEST 2. In some configurations the positions of the FLAP ASYM test switch are TEST and RESET. Maintenance and Test Panel (MTP) Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 17 3. Flap Position Control-Unit Test On the front panel of the FPCU is a 3-position toggle switch. In the TEST position the following occurs: - a difference between the selector position and flap position is simulated. - as a result the DISAGREE magnetic indicator on the FPCU shows yellow and the CAP gives a FLAP alert. - a cable separation is simulated and therefore the CABLE DISCON magnetic indicator shows yellow and the hydraulic flap operation is not more possible. - the ALTER MODE magnetic indicator shows yellow. In the RESET position the magnetic indicators are reset. Hydraulic flap operation will start again as soon as the flap selector is operated Flap Position Control-Unit (FPCU) above forward Cargo Door TEST Position sets magnetic indicators Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 18 2.4 Maintenance Intervals The inspection intervals for cables, components and lubrication depend on the location and function Alternate Flap Position indication (typical example) Take-off Flap Setting Landing Flap Setting Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 19 3 LOCATION OF COMPONENTS Component Location Cable separation detector In pedestal Electric motor relay In rear of left main gear Flap position control unit Above forward cargo door Flap asymmetry transducers One on each outer flap support hinge Flap power drive unit On main gearbox Flap position indicator In main instrument panel, center Intermediate gearbox In right main gear bay, ceiling Limit switches Along the outboard spindle of the left inner flap Main gearbox In left main gear bay, ceiling Mechanical stops On outboard spindle, of the left inner flap Fokker 50/60: 27-07 Code 3001N/Issue 1 Page 20 Stall Warning Description and Operation/Maintenance Information Table of Contents 1 STALL WARNING......................................................................................................................... 2 1.1 1.2 Introduction ................................................................................................................................... 2 Components.................................................................................................................................. 2 • Angle-of-Attack Transducer .................................................................................................... 2 • Stick Shaker ............................................................................................................................ 2 Electrical Circuit ............................................................................................................................ 4 • Configuration 1 (vane type 1).................................................................................................. 4 • Configuration 2 (vane type 1).................................................................................................. 5 • Configuration 3 (vane type 2).................................................................................................. 6 • Configuration 4 (vane type 2).................................................................................................. 7 1.3 2 MAINTENANCE INFORMATION ................................................................................................. 9 2.1 2.2 2.3 Maintenance and Test Panel ........................................................................................................ 9 Angle-of-Attack Transducer .......................................................................................................... 9 Drain of Angle-of-Attack Transducer (type 1) ............................................................................. 10 Fokker 50/60: 27-08 Code 3001N/Issue 1 Page 1 1 STALL WARNING 1. Introduction The function of the stall warning system is to give a pre-stall alert to the pilot when the aircraft attitude comes near a stall condition. To maintain lift at a low airspeed, the angle-of-attack (AoA) increases. When this angle is above the critical angle, the aircraft wing gets into a stall. Before this situation occurs the aircraft starts to shake, which is a natural alert. In the approach, however, when the flaps are down the speed difference between this natural behavior and the actual stall is very small. Therefore an alert informs the pilot before the stall condition occurs. The stall warning systems operates a stick shaker on the control column. It disconnects the auto pilot and yaw damper and gives a discrete to the ground-proximity warning system (GPWS). The stall warning systems operates in flight only. For maintenance purposes there is a test switch on the Maintenance and Test Panel (MTP). 2. Components • Angle-of-Attack Transducer There are two different vane-type transducers. The unit is installed on the right forward side of the fuselage. This transducer senses the angle-of-attack. When this angle is too much a switch closes, which starts the operation of the stick shaker when the aircraft is in flight. The vanes have one or two heating elements to prevent ice formation. The transducers are installed in the pressurized area. To overcome the difference with the outside pressure (for type 1) a balance line is installed between the housing and the forward pressure bulkhead. This also stops water ingress to prevent a frozen vane position. • Stick Shaker The stick shaker is on the left control column. It causes the two control columns to shake when the aircraft angle-of-attack gets to more than 17,5° (or 14°, depending on flap position) in flight. The stick shaker assembly has an electric motor which drives an eccentric weight. Some aircraft have a two channel system. Fokker 50/60: 27-08 Code 3001N/Issue 1 Page 2 Location of Components A B View B View A Stick Shaker Angle-of-Attack Transducer Forward Pressure Bulkhead Types of Angle-of-Attack Transducers Type 1 Fokker 50/60: 27-08 Code 3001N/Issue 1 Type 2 Page 3 3. Electrical Circuit • Configuration 1 (vane type 1) When the pilot operates the VANE pushswitch to on and the aircraft is in flight the stall-warning main-relay de-energizes. Stall sensing and vane heating are now on. When there is an open circuit in the heating element the current sensor supplies a discrete to the IAU. When the angle-of-attack is more than 17,5° a contact in the transducer closes. This supplies electrical power to the stick shaker. There is also an input for the auto pilot and the GPWS. When the aircraft touches down a ground/flight relay stops the electrical supply to the transducer and the heating element. Note: This configuration has a common DC Current Sensor for vane heating and L LO pitot mast heating. Electrical Control (transducer type 1) 28V DC DC BUS1 IAU LEVEL 2 DCBUS1 ON A/CIN FLIGHT ARM INH TD 1S TAKE-OFF STALL WRN G MAIN STALL TEST TEST MTP GND VANE FLT FAULT OFF OFF TRANSDUCER VANE HEATING CTL AUTO PILOT AND GPWS DISCONNECT STICK M SHAKER == 2735-001D Fokker 50/60: 27-08 Code 3001N/Issue 1 CURRENT SENSOR OK CURRENTSENSOR VANE/PITOT Page 4 • Configuration 2 (vane type 1) The difference between configuration #1 and #2 is a circuit for heating on the ground. Reduced heating power is available after touch-down through a resistor. Note: This configuration has a common DC Current Sensor for vane heating and L LO pitot mast heating. Electrical Control (transducer type 1) 28V DC DC BUS1 IAU LEVEL 2 ARM DCBUS1 ON INH TD 3S TAKE-OFF STALL WRN G MAIN GND FLT STALL TEST FLT GND VANE TEST FAULT OFF MTP OFF TRANSDUCER VANE HEATING CTL AUTO PILOT AND GPWS DISCONNECT STICK SHAKER 2735-002D Tasks Fokker 50/60: 27-08 Code 3001N/Issue 1 M == CURRENT SENSOR OK CURRENTSENSOR VANE/PITOT Page 5 • Configuration 3 (vane type 2) This configuration has a transducer with two switches. The stick shaker operates when: - the vane angle is 14° or more with a flap position of more than 22°, or - the vane angle is 17,5° or more and the flap position is less than 22°. The Flap Position Control-Unit (FPCU) supplies a 22° discrete to IAU. The IAU controls the Flap Position relay. Electrical Control (transducer type 2) 28V DC DC BUS1 IAU LEVEL 2 ARM DCBUS1 ON STALL WRN G MAIN GND INH TD 3S TAKE-OFF FLT VANE FAULT STALL TEST OFF TEST OFF VANE HEATING CTL MTP >14° >17,5° TRANSDUCER OK FLAP POSITION >22° CURRENT SENSOR AUTOPILOT ANDGPWS DISCONNECT STICK M SHAKER == Fokker 50/60: 27-08 Code 3001N/Issue 1 2735-007D Page 6 • Configuration 4 (vane type 2) This configuration has two Stall Warning channels, one for the left and one for the right control column. Each system has: - a stick shaker on the control column - an angle-of-attack transducer with two switches, one at 14° and one at 17.5° - a VANE pushswitch. Note: The 14° switch in the transducer is not used. DC Bus 2 supplies electrical power for the right system. Electrical Control (transducer type 2) 28V DC DC BUS1 IAU LEVEL 2 ARM DCBUS1 ON STALL WRN G MAIN GND INH TD 3S TAKE-OFF FLT VANE FAULT STALL TEST OFF TEST OFF VANE HEATING CTL MTP LH SYSTEMSHOWN RHSYSTEMSIMILAR >14° >17,5° TRANSDUCER OK CURRENT SENSOR AUTOPILOT ANDGPWS DISCONNECT STICK SHAKER Fokker 50/60: 27-08 Code 3001N/Issue 1 M == 2735-009 Page 7 Ice Protection Panel for the two Angle-of-Attack Transducers system Fokker 50/60: 27-08 Code 3001N/Issue 1 Page 8 2 MAINTENANCE INFORMATION 2.1 Maintenance and Test Panel On the MTP is the STALL TEST switch. You can do a test while the aircraft is on the ground. Maintenance and Test Panel (MTP) 2.2 Angle-of-Attack Transducer A special tool is required to adjust the angle-of-attack transducer. Leveling Pins Rigging Pins Rigging Tool Angle-of-Attack Tranducer Vane Fokker 50/60: 27-08 Code 3001N/Issue 1 Page 9 2.3 Drain of Angle-of-Attack Transducer (type 1) A drain removes any moisture which enters the housing of the transducer during flight. The drain is in the forward pressure bulkhead. Nose Wheel Bay Drain of Angle-of-Attack Transducer Fokker 50/60: 27-08 Code 3001N/Issue 1 Page 10 Take-off Warning Description and Operation Table of Contents 1 TAKE-OFF WARNING.................................................................................................................. 2 1. 2. 3. Introduction ................................................................................................................................... 2 Description and Operation ............................................................................................................ 2 Operational Test ........................................................................................................................... 4 Fokker 50/60: 27-09 Code 3001N/Issue 1 Page 1 1 TAKE-OFF WARNING 1. Introduction The Take-off Warning system informs the pilot during the take-off in case the aircraft is not in the correct take-off configuration. A red warning legend on the Central Annunciator Panel (CAP) comes on when the pilot moves the POWER levers to TO (take-off) and one of the monitored items is not in the correct mode. 2. Description and Operation The Take-off Warning System causes the red TO CONFIG light on the Central Annunciator Panel (CAP) to come on when the aircraft is not in the correct take-off configuration. This is when the aircraft is on the ground, the engines run and the pilot moves the POWER levers in the TO (Take-off) position while one of the following items is not correct: - the flaps are not in the take-off position - the rudder trim is not in neutral - the elevator trim is not in the take-off range - the parking brake is set - the engine rating selection is not in a take-off rating - the Auto Feathering System is not armed. The level 3 alert is non-resettable. Fokker 50/60: 27-09 Code 3001N/Issue 1 Page 2 Fokker 50/60: 27-09 Code 3001N/Issue 1 Page 3 3. Operational Test The pilot pushes the TO CONFIG pushbutton on the flight-deck test panel before take-off to make a check whether the aircraft is in the take-off configuration. The operation of this test-pushbutton simulates that the parking brake is off and the POWER levers are in the TO detent. As a result the pilot can make a check whether: - the flaps are in a take-off position - the rudder trim is in neutral - the elevator trim is in the take-off range - the engine rating selection is in a take-off rating. Flight-Deck Test Panel Test Button Fokker 50/60: 27-09 Code 3001N/Issue 1 Page 4
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