Systems Guide

Aerosoft
Airbus A320/A321
SYSTEMS
Systems guide
Vol
4
04-03-37
28 October 2014
There seven flight control computers that process the pilot inputs:
 2 ELAC’s (Elevator Aileron Computer)
 3 SEC’s (Spoiler Elevator Computer)
 2 FAC’s (Flight Augmentation Computer)
PITCH CONTROL
The two elevators and THS control pitch. The pitch is normally controlled by ELAC 2 and uses the green and yellow
hydraulic systems. The THS uses three electrical motors. Mechanical control using the THS always overrides the
electrical controls, but has limited elevator travel.
ROLL CONTROL
One aileron and four spoilers on each wing control roll. Roll control is normally controlled by ELAC 1, using the
blue and green hydraulic systems. Spoiler control uses SEC 3, using the green, yellow of blue hydraulic systems.
YAW CONTROL
In flight yaw control is fully automatic and the yaw orders are computed by the ELACs and handled by the FACs.
One rudder surface is used. Mechanical control is always possible and overrides the electrical controls. The single
rudder surface is moved by 3 hydraulic jacks using the green hydraulic system with a yellow hydraulic backup.
Rudder deflection is limited as a function of speed.
Yaw trim is achieved by two electric motors. In automatic flight the FACs and FMCG controls the rudder. In
manual mode the RUD TRIM rotary control on the pedestal can be used. The reset button will center the rudder.
Rudder trim and reset is NOT active when A/P is used.
FLARE MODE
When passing 50 feet on landing the flight mode changes to flare mode and the attitude is maintained. At 30 feet
the aircraft will start a pitch down maneuver to 2° nose down and gentle positive pilot action is required.
SPEED BRAKES AND GROUND SPOILER CONTROL
Spoiler 2, 3 and 4 are used as speed brakes and controlled by the speed brake lever. Speed brakes cannot be used
in flaps configuration 3 and FULL or when angle of attack protection is active.
Ground spoilers are armed when the speed brakes control lever is pulled in to armed position. It uses spoiler 1 to
5. They will extend automatically:
 At landing when both main wheels touch down and throttle is at forward idle
 At take off when reverse is selected on at least one engine and speed is over 75 knots.
OVERHEAD PANEL CONTROLS
There are two FLT CTL panels on the overhead panel. When the corresponding system is ON and without fault the
pb will be dark. When clicked OFF will show and the corresponding computer will be deactivated. When clicked
again the computer will reset and restart. The two panels are mixed so each crew member will be able to control
at least one ELAC, SEC and FAC.