Systems Guide

A318/A319/A320/A321
Professional
SYSTEMS
Systems guide
Vol
4
04-03-13
11 July 2018
• The autopilot is automatically disengaged when the throttles are set above FLX/MCT on ground.
• The autopilot is automatically disengaged when a normal law is exceeded, or pitch or bank angle
are excessive.
• The autopilot is automatically disengaged during a non-precision approach when the aircraft
reaches MDA minus 50 feet.
AUTOPILOT & SPEED BRAKES
With the autopilot engaged the speed brakes are limited to ½ deflection. When autopilot is engaged with
speed brakes extended beyond ½ they will retract to ½. Note this will cause a sudden pitch up.
AUTOTHRUST
The autothrust system reduces workload for the pilot, provides additional comfort for the passengers and
reduces fuel use. Two main modes are included:
• Fixed Thrust Modes
o Uses constant thrust; airspeed is controlled with pitch. Normally used for level changes
when no specific vertical speed is required.
• Variable Thrust Modes
o In variable thrust mode the airspeed remains constant by changing the amount of
thrust. Normally used for level flight or when a certain airspeed is required during level
change.
AUTOTHRUST ARMING STATUS
When autothrust is OFF the thrust is controlled manually and corresponds to the position of the trust
levers. When autothrust is ARMED and the thrust levers are moved into the A/THR active the autothrust
status changes to ACTIVE. The status is shown on the FMA (blue indicates armed mode and white
indicates active mode). Autothrust is automatically armed during takeoff when thrust levers are in the
TOGA or FLX detent.
AUTOTHRUST ACTIVE STATUS
The autothrust system controls thrust only in active status. Both fixed (MCT, CLB, IDLE, THR) and variable
thrust (SPEED, MACH) modes are available in active status.
AUTOTHRUST DEACTIVATION
The autothrust system can be disabled by depressing the FCU A/THR pb or by retarding the throttles to
the idle detent. A single chime and a short amber master caution illumination alerts the pilot.