FCU - Flight Control Unit
The Flight Control Unit (FCU) provides controls and indicators which affect both the aircraft's attitude and the other display windows (ND & PFD). It is broken into two parts:
- Electronic Flight Information System (EFIS) Control Panel. This affects what is shown in the Nav Display (ND) and Primary Flight Display (PFD) windows.
- Autopilot/Autothrottle Control Panel. These controls implement familiar autopilot (AP) and autothrottle (AT) functions.
The knobs on the panel have different behavior for the left mouse button (LMB) vs. the right mouse button (RMB). Be sure you know which function you want when you click on a knob.
EFIS Control Panel
The controls in this section of the FCU window primarily affect the ND window. As you would expect, the altimeter adjustments affect the altitude shown in the PFD.
Altimeter adjustment
The FCU reads the same flight simulator variables as any other panel. Using the flight sim command to automatically set the altimeter will change the value shown in the vasFMC FCU. Naturally, you can also set it manually.
- Left click on the knob to enable altimeter changes.
- Left click on either in Hg to set the altimeter using imperial units, or hPa to use metric units.
- Use the mouse wheel over the knob to scroll the display to the desired setting. You can also click to the left or right of the knob to increase or decrease the value.
- Right click on the knob to set standard pressure (STD). This disables changes - left click to enable changes again.
- The altimeter displayed in the PFD will change with this selection. When STD pressure is set the PFD will display the altitude set as a flight level (FL). For example, 24,000 ft would be shown as "FL240" at STD pressure, but "24000" at any other pressure.
ND & PFD control
- To select the ND display mode, left/right click to rotate the knob left/right. You can also use the mouse wheel over the knob to scroll through the selections.
- To select the range displayed by the ND, left/right click to rotate the knob left/right. You can also use the mouse wheel over the knob to scroll through the selections. Note that the selected distance represents the width of the display. Modes which have the aircraft in the center will extend half as far. That is, the selected distance is the diameter so the radius is half as wide.
- To select whether VOR1, ADF1 or nothing is shown in the lower left of the ND, click the VOR/ADF/OFF selections under the left knob (1). The lower right display is similarly controlled by the VOR/ADF/OFF selections under the right knob (2).
- To turn on/off the display of airports (ARPT), NDBs, VORs or crossing restrictions (CSTR), click the corresponding button above the knobs. Note that by default only airports with runways 2000m or longer will be shown. This helps declutter the ND, especially in large urban areas.
- To show the ILS indicators on the PFD, click the ILS button under the altimeter knob.
- To show the flight director (FD) arrows on the PFD, click the FD button under the altimeter knob.
Flight Control Unit (FCU)
Autothrottle (AT)
The autothrottle (AT) controls let you hold a set speed, the current speed or a given N1 percentage (N1 is used only on turbojets & turboprops).
- Select Indicated Airspeed (IAS) or Mach by clicking the SPD/MACH button.
- To hold the current speed, click the A/THR button to arm the AT. Then left click on the speed knob to engage AT. The display will change to show the speed being held, and the AT will adjust the engine power as needed to hold the given speed (up to the engine(s) limit). The light above the button label will come on and SPD will show in the PFD.
- To change the set speed, scroll the mousewheel over the speed set knob. You can also click to the left/right of the knob to decrease/increase the set speed.
- To hold a given N1 %, set the percentage of climb thrust on the MCDU PERF climb page. Then click the small screw next to the LOC button. The N1 indicator will show in the PFD.
- To disengage the AT, click the A/THR button. The light above the label will go out along with the SPD indicator on the PFD.
Important: If you enabled the Airbus
Throttle mode on the MCDU MENU/SETTINGS page, the At will behave
differently.
Take a look into the advanced flight chapter for details.
Altitude setting
You can set a desired altitude and rate of climb/descent and the autopilot (AP) will manage the aircraft's pitch to achieve the goal you set (up to the aircraft's limits). The AP must be engaged for the controls to take effect.
To set the desired altitude:
- Left click to the left/right of the altitude knob to change the altitude by 100 feet. You can also scroll the mousewheel over the knob to change in 100 foot increments.
- Right click to the left/right of the altitude knob to change the altitude by 1000 feet.
- Left click to the left/right of the rate knob to change the rate by 100 feet. You can also scroll the mousewheel over the knob to change in 100 foot increments.
- Right click to the left/right to change the rate by 1000 feet.
Speed dependend climb/descend (OP CLB/DES, FLCH):
- Left or right click on the altitude knob to enable the flight level change mode. In this mode, the thrust and the speed (IAS or MACH) will be fixed and the actual climb/descent rate depend on the aircraft performance and the environment (altitude, wind changes, etc.).
To level off at the current altitude and enter V/S hold mode:
- Left click on the V/S rate knob. Note that the actual altitude reached will depend on how quickly the aircraft responds to the V/S change. The preset altitude will not be changed. This is one way to effect a stepped climb or descent. The PFD will still show the ALT indicator.
To hold the current vertical speed (climb or descent) and enter V/S hold mode:
- Right click on the rate knob.
Lateral navigation (LNAV)
You can set the FCU to control the aircraft's heading either in a fixed direction or to change directions as needed to follow the current flight plan. The AP must be engaged for the controls to take effect.
To toggle flight plan following (LNAV):
- Left click on the heading knob to enable lateral navigation (LNAV).
- When vasFMC is following the flight plan the ND will show a solid flight plan line. The PFD will show (L)NAV. The heading indicator on the FCU will show "---" to show that the heading will follow the flight plan.
- When vasFMC is not following the flight plan the ND will show a dashed flight plan line. The PFD will show HDG. The heading indicator on the FCU will show the current heading bug setting.
To fly the current heading and enter the HDG mode:
- Right click on the heading knob.
- When tracking the current heading the heading bug will be set to the current heading and the autopilot heading mode will be engaged.
To set the heading bug:
- Left click to the left/right of the knob to change the heading by 1 degree. You can also scroll the mousewheel over the knob.
- Right click to the left/right of the knob to change the heading by 10 degrees.
Approach control
There are two buttons which will follow an ILS. Before the FCU can follow the signal, the ILS frequency must be set in NAV1 and an ILS signal must be received.
To have the FCU track only an ILS localizer:
- Click the LOC button. This will turn off APPR. The PFD will show LOC.
To have the FCU track both the localizer and glideslope:
- Click the APPR button. This will turn off LOC. The PFD will show LOC and G/S.