Ata 27 Fcs System Overview.docx

27 - Flight Controls Level 2 27 - Flight Controls Level 2

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SYSTEM OVERVIEW 2

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 Control surfaces The control is achieved through the following conventional surfaces. PITCH 3

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Pitch achieved by: o Elevator o THS Pitch control is achieved by two elevators and the Trimmable Horizontal Stabilizer (THS). Elevators are used for short-term activity. The THS is used for long-term activity. ROLL 4

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Roll achieved by: o Ailerons o Spoilers 2 to 5 Roll control is achieved by one aileron and spoilers 2 to 5 on each wing, numbered from wing root to wing tip. YAW 5

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Yaw achieved by: o Rudder o Yaw damper The rudder fulfills yaw control. The rudder is used during cross wind take-off and landing, and in case of engine failure (thrust asymmetry). The yaw damper function controls the rudder for Dutch roll damping and turn coordination. SPEED BRAKES 6

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Speed brake function fulfilled by: Spoilers 2 to 4 o Used in flight The speed brake function is used in flight to increase the aircraft drag. Spoilers 2 to 4 are used. Roll orders and speed brake orders are added with priority given to the roll function. GROUND SPOILERS 7

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Ground spoiler function fulfilled by all spoilers o In case of landing or aborted take-off

The ground spoiler function is used to destroy the lift during landing and in case of aborted take-off. All spoiler panels are used. AILERON DROOP 8

 Aileron droop function increases lift The aileron droop function increases the lift on the part of the wing which is not equipped which flaps. The ailerons are deflected downwards when the flaps are extended. HIGH LIFT 9

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High lift function fulfilled by: o Slats o Flaps  Double slotted flaps on A321 Slats and flaps achieve the high lift function. There are two flaps, inboard and outboard, and five slats on each wing, numbered from wing root to wing tip. The A321 is equipped with double slotted flaps. 10

 Electrically controlled and hydraulically operated  2 SFCCs with slat and flap channels The slats and flaps are electrically controlled and hydraulically operated. Two Slat Flap Control Computers (SFCCs) ensure control and monitoring. Each computer has one slat and one flap channel. The slat and flap systems are similar. 11

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Systems driven by PCUs o 2 hydraulic motors o Torque shafts and gearboxes transmit mechanical power A Power Control Unit (PCU) drives each system with two hydraulic motors coupled to a differential gearbox. Torque shafts and gearboxes transmit the mechanical power to the actuators, which drive the surfaces. 12

 Valve block controls the direction of rotation and speed  POB locks transmission Each motor is powered by a different hydraulic system and has its own valve block and Pressure Off Brake (POB). Valve blocks control the direction of rotation and the speed of their related PCU output shaft. The POB locks the transmission when the slat and flap surfaces have reached the selected position or if hydraulic power fails. 13

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WTB stop and lock the system o Reset on ground

Wing Tip Brakes (WTBs) are provided in order to stop and lock the system when major failures are detected. They are hydraulically activated and can only be reset on ground. 14

 PPU sent slat and flap position feedback Position Pick-Off Units (PPUs) send slat and flap position feedback to the SFCCs and ECAM. 15

 Flap sensors to detect failures  Signals sent to the SFCCs via the LGCIU Flap sensors installed between inboard and outboard flaps inhibit further flap operation when a flap attachment failure is detected. The signal is sent to the SFCCs via the Landing Gear Control and Interface Units (LGCIU). To prevent an aircraft stall, slats cannot be fully retracted at high angles of attack or low speeds (Alpha/speed lock function). COMPUTERS 16

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 Computer arrangement A computer arrangement permanently controls and monitors the flight control surfaces, it also records and stores faults. This arrangement includes: 17

 2 Elevator Aileron Computers  3 Spoiler Elevator Computers  2 Flight Augmentation Computers  2 Flight Control Data Concentrators  2 Flight Management Guidance Computers  2 Slat Flap Control Computers - 2 Elevator Aileron Computers (ELAC) for pitch and roll control, - 3 Spoiler Elevator Computers (SEC) for pitch and roll control, - 2 Flight Augmentation Computers (FAC) for yaw control, - 2 Flight Control Data Concentrators (FCDC) for indication and maintenance tests, - 2 Flight Management Guidance Computer (FMGC) for autopilot commands, - 2 Slat Flap Control Computers (SFCC) for slat and flap control. ACTIVE SERVO CONTROLS 18

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2 servo controls for each aileron, for each elevator and for the yaw damping function Normal configuration : 1 active servo control, 1 in damping mode centering mode applied to the only manual pitch trim available elevators. Actuators hydraulically maintained in neutral position.

There are two servo controls for each aileron, for each elevator and for the yaw damping function. In normal configuration, one servo control actuates the surface. It is called active servo control. The second, which follows the surface deflection, is in damping mode. When only manual pitch trim is available, the centering mode is applied to the elevators. The actuators are hydraulically maintained in neutral position. RECONFIGURATION PRIORITIES 19

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Servo loop control in normal configuration Priorities in case of computer failure or loss of hydraulic circuits In normal configuration, the following computers ensure the servoloop control. The arrows indicate the actuation reconfiguration priorities in case of computer failure or loss of hydraulic circuits. DAILY CHECK 20

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Daily check includes external walk around: visual check of the flight control surfaces for general condition. During the daily check, the external walk around will include the visual check for evidence of damage and fluid leakage of the: - Left and right wing leading edge slats, - Left and right wing trailing edge flaps and flap track fairings, - Left and right ailerons, - Left and right THS surfaces, - Left and right elevators, - Rudder. NOTE: The visual check of the Flight Control Surfaces is made from the ground with Flaps/Slats in the retracted position. MEL/DEACTIVATION AILERONS 21

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Aileron o 2 servocontrols o Reconfiguration priority + droop function  MMEL item  Deactivation procedure o Disconnect electrical connector & receptacle o Attach connector to a pipe with a tie-wrap As aileron servocontrol is a MMEL item, its deactivation is performed by disconnecting the related electrical connector. The detailed procedure is given in the AMM. SPOILERS

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1 servocontrol for each spoiler MMEL item Deactivation of the spoiler servocontrol procedure: o Symmetrical disconnection of ELEC plugs The spoiler servocontrol is a MMEL item. To deactivate the spoiler servocontrol, disconnect the electrical connector from the receptacle of the servocontrol. The detailed procedure is given in the AMM. ELEVATORS 23

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2 servocontrols for each elevator MEL item If ECAM & CFDS warnings o Servocontrol position XDCR swapping The elevator servocontrol position transducer (XDCR) is a MMEL item. If an ECAM warning "ELEVator SERVO FAULT "appears with a Centralized Fault Display System (CFDS) message "USE STandBY XDCR", the two plugs of the elevator servocontrol position XDCRs must be swapped. Detailed procedures are given in the AMM. ELAC 24

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If total electrical power failure o ELAC 1 is supplied via CSM/G (B servo controls) o ELAC 2 is powered at L/G extension (G & Y servo controls)  MMEL item o ELAC 2 inop: NO GO o ELAC 1 deactivation There are two ELACs (ELAC 1 and 2). Both ELACS are MEL items. Inoperative ELAC 2 is a NO GO item. Except for Extended Range (ER) operations, ELAC 1 or any ELAC 1 function may be inoperative provided all the MMEL restrictions are applied. Maintenance procedures related to ELAC 1 deactivation are detailed in the AMM. SEC 25

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MMEL item o Only one SEC inoperative o SEC deactivation There are three SECs.

Only one SEC out of three can be inoperative and deactivated provided all MMEL restrictions are applied. Maintenance procedures related to one SEC deactivation are detailed in the AMM. FAC 26

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MMEL item o FAC 1 inop: NO GO o FAC 2 deactivation There are two FACs (FAC 1 and FAC 2) are installed on the A/C. An inoperative FAC 1 is a NO GO item. FAC 2 may be inoperative and deactivated provided all MMEL restrictions are applied. Maintenance procedures related to FAC 2 deactivation are detailed in the AMM. FCDC 27

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MMEL item o FCDC 1 inop: NO GO o FCDC 2 inop: deactivation There are two FCDCs are installed on the A/C. An inoperative FCDC 1 is a NO GO item. FCDC 2 may be inoperative and deactivated following a flight crew procedure. SFCC 28

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SFCC 1&2: control & monitoring SFCC 1 inop: NO GO item SFCC 2 inop: MMEL restrictions o Slats & flaps operable on SFCC 1 o Operation of SFCC 1 WTB confirmed by test before each flight o All ELAC, SEC, LGCIU, RA, FAC & ADIRS operative o Takeoff in CONF 1+F not available (only for SFCC 2 slat channel inoperative) SFCC1 and SFCC2 monitor and control the flaps. An inoperative SFCC 1 is a NO GO item. Only SFCC 2 flap and slat channel may be inoperative provided all restrictions given in the MMEL are applied. WTB 29

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MEL items: o WTB solenoids associated to SFCC2

1 or 2 solenoids INOP if SFCC 1 associated WTB checked On SLAT or FLAP WTBs, one or two solenoids associated with SFCC 2 may be inoperative provided operation of SFCC 1 WTB is confirmed by a test before each flight. The related procedure for deactivation of the WTB solenoid is detailed in the AMM. MAINTENANCE TIPS - EXT/RET OF THE SPOILERS o

EXTENSION 30

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Extend the slats and flaps Depressurize the hydraulic systems Install the LOCKING TOOL -FLAP/SLAT CONTROL LEVER (98D27803000000) on the flap/slat control lever.  Deactivate spoilers electrical control (pull CBs)  Install the SPOILER MAINTENANCE KEY (98D27603002001) on the servocontrol. To be unlocked, the servo control actuator must be depressurized. After the Flaps full extension the Slats/Flaps Locking Tool must be installed on the flap/slat control lever. Deactivate the spoilers electrical control by pulling the corresponding Circuits Breakers. The maintenance unlocking device tool can be engaged by using a key equipped with a red flame. This tool cannot be removed when the servo control is in maintenance mode. SAFETY COLAR INSTALLATION 31

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Move the spoiler to the extended position by hand. Put the COLLAR-SAFETY, SPOILER (98D27604000000) on the rod of the servocontrol. Once the maintenance-unlocking device is engaged the spoiler surface can be raised manually for inspection purposes. After the spoiler is fully raised by hand, install the Safety Collar on the servocontrol rod. RETRACTION 32

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Spoiler retraction: do opposite sequence with hydraulic systems depressurized Remove the COLLAR-SAFETY SPOILER (98D27604000000) from the rod of the servocontrol. Lower spoiler by hand to retract Remove the SPOILER MAINTENANCE KEY

(98D27603002001) from the servocontrol  Reactivate spoilers electrical control (push CBs)  Do the operational test of the spoiler hydraulic actuation (Ref.TASK 27-64-00-710-001)  Remove the LOCKING TOOL -FLAP/SLAT CONTROL LEVER (98D27803000000) on the flap/slat control lever.  Retract the slats and flaps  Depressurize the hydraulic systems To retract the spoiler, the Safety Collar must be removed from the servocontrol rod. When the maintenance unlocking device tool is turned and disengaged, the spoiler servocontrol is back to active mode. Reactivate the spoilers electrical control by reengaging the corresponding Circuits Breakers. Do the operational test of the spoiler hydraulic actuation. Return the aircraft to the initial configuration (retract Flaps/Slats).

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