A320 FLIGHT CONTROL UNIT

SPD/MACH knob

Display range: between 100 and 399 kt for speed, between 0.10 and 0.99 for Mach number.
One rotation of the knob corresponds to approximately 32 kt or M 0.32.

Pushing this pushbutton changes the SPD target to the corresponding MACH target and vice versa.

Pushing this pushbutton arms, engages, or disengages the LOC mode or the LOC B/C mode.

The flight crew uses this pushbutton to select HDG (associated with V/S) or TRK (associated with FPA). Pushing it:

Displays the Flight Path Vector (FPV) on the Primary Flight Display (PFD) or deletes it.
On the PFD, changes the FD crossbar display (with the aircraft attitude as its reference) to the aircraft Flight Path Director (with the flight path vector as its reference) and vice versa.
Changes heading reference into track reference in the HDG/TRK window and vice versa.
Changes vertical speed reference target into flight path angle reference target in the V/S-FPA window and vice versa.

The flight crew uses these pushbuttons to engage or disengage the autopilots. The buttons illuminate green when the autopilot is engaged.
In normal procedures, the autopilot is not disengaged by pressing the AP buttons on the FCU but by pressing the takeover pushbutton on the sidestick.

The flight crew uses this pushbutton to arm, activate, or disconnect the autothrust (A/THR). This button illuminates green if the A/THR is armed or active.
In normal procedures the Autothrust is not disengaged by pressing the A/THR button on the FCU but by pressing the disconnect pushbutton on the throttle levers or by setting both thrust levers to idle.

Display range: 100 to 49 000 ft

The outer knob has two positions: 100 and 1000
The inner knob sets the altitude in the FCU window in increments of 100 or 1 000 ft, depending upon the position of the outer knob.

This pushbutton engages the expedite mode, which is used in climb or descent to reach the desired altitude with the maximum vertical gradient.

This pushbutton is used to display the FCU altitude target in meters on the ECAM, or the current altitude and FCU/FM altitude target in meters on the PFD.

For V/S mode, the range of this value is from - 6000 to + 6000 ft/min
For FPA mode, the range of this value is from - 9.9° to + 9.9° descent/climb angle.
When the flight crew pushes the V/S or FPA knob, the system commands an immediate level-off by engaging the V/S or FPA mode with a target of zero. When the aircraft V/S or FPA becomes zero, the FMA displays V/S = 0. If the flight crew then turns the knob to set a new value for V/S or FPA, the aircraft changes flight path accordingly.

This pushbutton arms, disarms, engages, or disengages the approach modes:

LOC and G/S modes, if an ILS approach is selected in the active F-PLN.
APP NAV-FINAL modes, if a non precision approach is selected in the active F-PLN.

A320 Guide ⮞