How To Use The Airbus Autopilot in Aerofly FS

The Flight Control Unit (FCU) is a box in the glareshield, right in the center of the flight deck. It contains of two EFIS control panels, one for each pilot, and the Auto-Flight-System Control-Panel (AFS CP). The latter is the interface to the autopilot with knobs and buttons to activate modes of the autopilot.

From left to right the knobs on the autopilot control

• Speed
• Direction/Heading
• Altitude
• Vertical Speed

These knobs can be pushed and pulled and there are also buttons next to the knobs to activate specific modes.

The Flight Mode Annunciator (FMA) is the most important instrument when using the autopilot. The FMA is the upper section of the primary flight display (PFD) and it displays to the pilot what the autopilot is currently doing and what modes have been activated.

The FMA is split into several columns:

• Active Auto-Thrust mode and in newer Airbuses Auto-Brake mode
• Active and armed vertical mode as well as armed vertical approach mode
• Active and armed lateral mode
• Information about approach capabilities of the aircraft and approach minima
• Autopilot, Flight-Director and Auto-Thrust engagement status

Superimposed on the attitude indicator of the primary flight display (PFD) we can see the flight director (F/D), visible as a horizontal and vertical green line. The flight director can be turned on and off for by pressing the F/D buttons on either side in the A320 or the single F/D button in center of the panel on the A380. When both flight directors are off and the autopilot is also off the entire system is turned off and is reset.

The horizontal flight director bar moves up and down to indicated the target pitch attitude. When the bar moves up you should pitch up to catch the bar with the current attitude. The bar moves back to the center when you are at the target pitch angle.

The vertical flight director bar moves left and right to show a target bank angle. When you roll to the side of the deflection the flight director bar moves back towards the center to indicate that you are at the target bank angle.

The autopilot sends digital signals to the flight control actuators which in turn move the flight control surfaces. The autopilot doesn’t move the passive sidesticks in the A320 and A380 so there is no direct feedback for the pilots on their control input devices. The pilots have the option to deflect the controls to immediately disengage the autopilot but this usually requires some break away force and the disengagement isn’t soft.

To engage the autopilot

• Select the desired modes with auto-flight-system control-panel (AFS CP)
• Confirm the selection on the flight mode annunciator (FMA)
• Push the AP1 or AP2 button, it turns green when the autopilot is engaged
• Release the side-stick

To disengage the autopilot correctly:

• Push the red takeover button on the sidestick

The A320 and A380 have auto-thrust systems (A/THR) which compute the thrust command for the engines. The thrust levers in the cockpit do not move automatically and the pilots can move them manually to override the system.

To use A/THR

• Push the A/THR button to arm the system, the button turns green when A/THR is armed
• Move the thrust levers to the CLB detent
• Pull the vertical speed knob to force the A/THR system into SPEED mode

To turn off the A/THR

• Move the thrust levers to idle
• Or push the instinctive buttons on the thrust levers

For route planning and long-term complex navigation functions the aircraft is equipped with a Flight Management System (FMS) that stores the flight plan and pre-programmed performance values and computes the most economical flight profile. Pilots can change the flight plan or enter values through either a Multifunction-Control-Display-Unit (MCDU) or a Multi-Function-Display (MFD) in the cockpit.

Per default the flight directors in the A320 and A380 are almost always turned on for you. You can toggle the flight directors with the FD buttons in the EFIS control panels. Turning them both off and back on resets all entered values.

• Push the FD buttons to toggle the flight directors

The light in the respective button should be green when the FD is on

The selected airspeed is used by the auto-thrust to control thrust in the SPEED mode and by the autopilot to pitch for the target speed when the auto-thrust is not holding the speed.

• Pull the airspeed knob to activate the selected airspeed mode
• Rotate the airspeed knob to set the target airspeed in knots in the digital display above it

We can instruct the autopilot to fly a specific heading. The autopilot will then turn left or right to fly the selected compass heading.

• Pull the heading knob to activate HDG mode
• Rotate the heading knob to set the desired heading

Using the vertical speed mode allows us to set the climb and descent rate directly. The autopilot will target the vertical speed and then level off at the pre-selected altitude once it comes near it.

• Rotate the altitude knob to set a new target altitude to capture
• Pull the vertical speed knob to activate the V/S mode
• Rotate the vertical speed knob to select a vertical speed value

When we are satisfied with the flight director guidance and the modes displayed in the flight mode annunciator (FMA) we can turn on the autopilot and auto-thrust system. To successfully engage an autopilot a couple of conditions have to be met first:

1. Airspeed above stall speed and below maximum speed, check that you are not currently flying too fast for the flap setting you have
2. Pitch angle between about 25° and -15° and bank angle less than 45°
3. Flight control inputs neutral and aircraft trimmed out
4. Aircraft in the air at least 100 feet above the ground after takeoff or above 400 feet prior to landing

• Push the AP1 button to engage the autopilot no. 1
• Neutralize your hardware-controls and release them
• Push the A/THR button to arm the auto-thrust
• Move your thrust levers to the CLB detent. Look down at the thrust levers in the virtual cockpit to confirm the thrust lever position

With the autopilot and auto-thrust engaged we can perform a climb or descent to a new target altitude using the OP CLB and OP DES.

• Rotate the altitude knob to set a target altitude
• Pull the altitude knob to command a flight-level change

The OP CLB or OP DES mode engages and the autopilot now pitches up and down to hold the target airspeed value. The auto-thrust system commands climb thrust during OP CLB and idle thrust during OP DES.

Note - If you are flying manually at this point be careful. You need to use pitch control to maintain airspeed, the auto-thrust system is not holding the airspeed for you in this mode! Use vertical speed mode instead if you want the auto-thrust to maintain speed for you.

The autopilot can follow the route all the way to the destination runway threshold. You first have to program a route using the Aerofly FS navigation menu or via MCDU or MFD in the cockpit.

With a route set up we can arm the lateral navigation:

• Steer the aircraft onto an intercept course with the route on the navigation display (ND)
• Push the heading knob in to arm the NAV mode

When the aircraft comes near the route it captures the route and NAV mode engages.

If you wish to edit the flight plan from within the cockpit and using the MCDU check out our dedicated MCDU tutorial:

When we have a route programmed we can tell the autopilot to fly the vertical profile of the route for us as well.

Note - The vertical navigation (VNAV) in the Airbus requires the NAV mode to be active. You cannot use the CLB and DES modes when you don’t have NAV engaged. Use OP CLB and OP DES when you are not following the route yet.

To climb to the cruise altitude or descent for the approach with NAV engaged

• Rotate the altitude knob to set a target altitude
• Push the altitude knob in to engage CLB or DES mode

The autopilot now pitches for the target airspeed whilst auto-thrust is commanding climb thrust or idle thrust. At the target altitude the autopilot levels off and thrust-mode changes back to SPEED.

When a route has been set up and you are near the route you can use the target airspeed computed by the flight management system (FMS) in the so called managed speed mode. The target speed depends on altitude, economical factors and speed constraints along the route.

• Push the airspeed knob to use managed speed

When the auto-thrust is in SPEED mode the aircraft will automatically accelerate or decelerate towards the target airspeed. During the approach phase the speed is kept high until you extend flaps, giving some speed control to the pilots.

And when the aircraft is climbing or descending the autopilot uses the speed target to pitch for the target speed. During the descent you might see a speed range instead of a fixed target speed, which allows the speed to vary slightly to decrease fuel consumption and maintain idle thrust for most of the descent.

During the ILS approach you may receive the clearance to intercept the localizer of a runway but are not yet given full approach clearance. This is when the LOC mode can be used. This mode requires you to have an ILS localizer frequency tuned, an ILS course set and a valid ILS localizer signal to be received.

• Push the LOC button to arm the LOC mode

The mode LOC will be shown in blue in the flight mode annunciator until the localizer moves off the full scale deflection towards the center. The autopilot then turns the aircraft onto the selected ILS course and intercepts the localizer in the LOC* mode. After localizer capture the mode changes to LOC tracking mode.

After receiving full ILS approach clearance we can start descending once we capture the ILS localizer beam. This approach mode requires you to have an ILS localizer frequency tuned, an ILS course set and a valid ILS localizer and glide-slope signal to be received.

• Push the APPR button to arm both the LOC and G/S modes

The localizer capture works exactly like in the localizer only mode. Once the LOC* or LOC mode is engaged the glide slope can be captured as well. This is indicated with a G/S* capture and G/S tracking mode on the flight mode annunciator.

When the LOC and G/S modes are both engaged and the runway is usable for an automatic landing and the aircraft systems allow it then you can let the autopilot land the aircraft for you in an ILS autoland.

• Capture the ILS LOC and G/S as described before
• Engage both autopilots AP1 and AP2
• Extend flaps and gear, arm ground spoilers and arm autobrakes like usual
• Reduce speed to final approach speed

At 400 feet above the ground the lateral and vertical modes combine to LAND. They then change to FLARE and ROLLOUT.

• At 10 feet above the ground when the RETARD callout is made, pull the thrust levers to idle
• Disengage the autopilot with the red takeover button on the sidestick when the landing is finished or when you want to vacate the runway

The autopilot is able to fly even a curved and sloped approach fully automatically. So called area navigation approaches (RNV-Approaches) rely on GPS signal and triangulation of radio-navaids to compute the aircraft position to a high degree of accuracy. This accuracy is not high enough to perform an automatic landing but with these approaches the airport doesn’t need to have an ILS installed on the runway that you want to land.

During a managed approach the autopilot uses the flight management system computed navigation route and vertical path and steers the aircraft to stay on the planned route. To use an RNV approach you first have to select it in the navigation menu or via the MCDU or MFD in the cockpit.

• Fly along the route with NAV mode and descent to the initial approach fix altitude
• Deselect the LS system display on the PFD as we won’t be needing it
• Push the APPR button to arm the approach

APP NAV will arm and engage once you are on the route. The FINAL vertical mode will arm and once you intercept the final approach segment the FINAL APP mode engages, combining the APP NAV and FINAL modes.

• At the minimum descent altitude disengage the autopilot and land manually

Non-Precision Approaches like VOR approaches can be flown using selected modes as well. During the final approach the TRK and FPA modes are used and small corrections are made by the pilot to steer towards the VOR needle and planned descent profile e.g. based on DME distance.

To fly a VOR approach

• Tune and identify the VOR station using the MCDU RAD/NAV page
• Set the VOR course on the MCDU RAD/NAV page
• Select the VOR rose mode on the navigation display (ND)
• Switch to the BIRD display by pressing the HDG/TRK VS/FPA pushbutton to select TRK FPA
• Pull the heading knob to engage TRK mode and rotate the knob to steer the aircraft left/right onto the VOR needle
• Pull the vertical speed knob to engage FPA mode rotate the knob to adjust the descent angle (typical -3.0°)
• At the minimum descent altitude disengage the autopilot and land manually

When the approach phase is active and when flaps have been extended the go-around mode becomes available. To perform a go-around:

• Move the thrust levers all the way forward to the TOGA detent

The auto-thrust disarms and MAN TOGA is shown in the flight mode annunciator. The vertical speed reference mode (SRS) engages and commands a pitch up to fly the go-around speed. The lateral mode changes to GA TRK (go-around track), which is the current track at the time of the go-around trigger.

• Retract gear and set go-around flaps
• Engage NAV mode to fly the go-around route or pull the heading knob and rotate it to fly a certain heading
• Pull the thrust levers back to CLB when you are above above the go-around thrust reduction altitude
• Pull the altitude knob if OP CLB is desired
• Pull the airspeed knob and set a desired speed if desired

When you want to come back around for landing

• Activate the approach phase on the MCDU

• Set target altitude
• Set thrust levers to FLX/MCT or TOGA
• Manually maintain centerline
• Rotate at VR
• Follow SRS flight director guidance
• NAV mode engages when you have a route, otherwise HDG engages
• Engage Autopilot
• LVR CLB flashing, move thrust levers to CLB at thrust reduction altitude

• After takeoff CLB mode engages when route is planned, otherwise OP CLB activates
• Climb to target altitude
• Autopilot levels off at selected altitude

When DECELERATE is shown on PFD:

• Select lower altitude for the approach
• Push altitude knob to initiate DES mode when you have a route planned, otherwise pull the knob for OP DES
• Use speedbrakes as needed

• Activate approach phase if flying without route or when not near route
• Maneuver on an intercept course with ILS localizer beam and descent to initial approach altitude (e.g. runway elevation + 2000 feet)
• Push APPR button to arm ILS approach
• LOC and G/S capture
• LAND mode engages automatically at 400 feet
• FLARE engages before touchdown at 50 feet
• Pull thrust lever to idle between 20 and 10 feet
• ROLLOUT engages after touchdown
• Disconnect autopilot to vacate runway

After takeoff, when you are in the air with the auto-thrust system turned on, you should keep the thrust levers in the CLB detent throughout the flight. When the thrust levers are above the CLB detent you are commanding manual thrust and you can see a LVR CLB message blinking in the FMA and MAN THR is shown.

When your thrust levers are below the CLB detent your maximum engine thrust is limited to your thrust lever position and auto-thrust cannot command more thrust. In this case LVR CLB is also flashing in the FMA and SPEED/THR CLB/THR IDLE is shown.

• Move your thrust lever to the climb (CLB) detent

Note - In case one engine is off the message shows LVR MCT and you should move the levers to the FLX/MCT detent instead.

During landing, shortly before touching down, a callout is made to remind you to close the thrust levers and set them to IDLE. The callout “RETARD, RETARD” is repeated until you have reduced thrust to idle or triggered a go-around.

During automatic landing (auto-land) the callout activates at 10 feet above the ground and during manual landing the callout comes on at 20 feet.

• Pull the thrust lever to IDLE

When the flaps are extended and you are below 2000 feet above the ground the aircraft monitors if your aircraft is getting too low on energy or too slow. When your flight path cannot be maintained with current engine thrust, e.g. you are getting dangerously low on airspeed and are approaching a stall condition, then the aircraft issues a “SPEED, SPEED” callout.

• Immediately increase thrust and lower the nose to pick up speed

The reason for this occurrence could be that you accidentally turned off the auto-thrust. Make sure that if you are flying manually that the auto-thrust is controlling airspeed by pulling the vertical speed knob.

When the auto-thrust system is active the minimum target airspeed for the A/THR is kept above the velocity low speed (VLS), a.k.a. velocity lowest selectable. The VLS is shown on the airspeed tape as a thin yellow line and it is based on flap setting, spoiler position and aircraft weight. The VLS is the first defense against a stall in an Airbus and it allows a level flight turn up to about 30 degrees without getting into the stall protection zone.

• Select a higher flap setting to decelerate further
• Retract speedbrakes to increase the stall margin
• Increase the selected airspeed above the VLS

When the angle of attack (alpha) is approaching a stall condition then the auto-thrust system turns on automatically in the ALPHA FLOOR (A.FLOOR) mode and commands full TOGA thrust to prevent the stall. When the angle of attack reduces again or when the pilot holds the side-stick forward for about one second to recover from the stall then the mode switches from A.FLOOR to TOGA LOCK (TOGA LK). During TOGA LK the TOGA thrust is kept until you manually move your thrust levers.

Notice that the active thrust mode on the flight mode annunciator (FMA) is now A.FLOOR or TOGA LK boxed in an amber color and flashing. On the engine display (upper ECAM) you can see an amber pulsating A.FLOOR or TOGA LK text.

• Push the nose down to recover from the approaching stall
• Add full TOGA thrust manually

When stall condition has been recovered - Move thrust levers to CLB

Note - You can cancel the A.FLOOR and TOGA LK modes by moving the thrust levers and setting them to idle or by pushing the instinctive auto-thrust disconnect buttons on the thrust levers. A.FLOOR won’t trigger again until the stall has been recovered and a new stall occurs.

When you hear a “Tick Tick Tick” (Triple Click, Triple Ticking sound) in the cockpit then the autopilot is trying to get your attention. Look at the flight mode annunciator (FMA) and check if any mode or indication is boxed in white or amber.

Some of the conditions that trigger the attention getter sound:

1. The lateral navigation is lost and the aircraft reverted to heading select
2. The vertical mode changed on its own without pilot action
3. The approach capability downgraded, e.g. after disconnecting the autopilot or auto-thrust
4. The selected vertical speed is excessive and the autopilot cannot maintain the selected vertical speed

• Double check the active modes and selected values and change them if needed

With the vertical speed mode (V/S) engaged the aircraft tries to pitch for the selected vertical speed target. This affects the airspeed and if climb thrust is not enough to stay above the stall speed or when even at idle thrust the aircraft still speeds up above the maximum allowed airspeed, then the vertical speed mode starts flashing in amber color on the FMA. The autopilot issues a triple clicking sound “Tick Tick Tick” and adjusts the vertical speed target to stay within the safe airspeed envelope.

• Check your airspeed and adjust the vertical speed target
• Increase thrust or increase drag if needed

During an ILS approach pilots should select the ILS needle display with their EFIS controller. If the autopilot is armed to intercept the localizer or is already capturing it then an amber “ILS” is flashing on the primary flight display (PFD) in the lower right corner of the attitude indicator to remind pilots to turn on the landing system display.

• Push the LS button on the EFIS controller to turn on the landing system display

When no ILS approach has been selected then the ILS needles should not be displayed on the primary flight display. If the pilots have turned on the landing system display but no ILS approach is planned, then the primary flight display shows an amber V/DEV flashing in the top right corner of the attitude indicator.

• Push the LS button on the EFIS controller to turn off the landing system display

When the active lateral mode can no longer be maintained then the autopilot reverts to the basic mode HDG. This change triggers the attention getter triple clicking sound (“Tick Tick Tick”) and the flight director lateral steering bar is flashing on and off. The lateral mode on the FMA is boxed in white and flashes for several seconds.

Reasons why this happened:

1. The NAV mode was active but you flew too far off the planned course or flew over the end of the flight plan
2. The LOC mode was active and the localizer signal was lost

• Verify the active lateral and vertical modes and change them as desired

When the active vertical mode can no longer be maintained then it automatically reverts to another mode. You can hear the attention getter triple click “Tick Tick Tick” and the vertical command bar of the flight director flashes on and off. The vertical mode on the FMA is boxed in white and flashes for several seconds.

Reasons why this has happened:

1. You pulled the heading knob when the G/S, CLB, DES, ALT CST or other modes where active which require the LOC or NAV lateral modes
2. You rotated the altitude knob when the autopilot was in the altitude capture phase (ALT* or ALT CST*)

• Adjust the altitude and pull the altitude knob if you wish to use OP CLB or OP DES modes
• Adjust the altitude and pull the vertical speed knob to set vertical speed mode

Note - If you have NAV or LOC mode engaged and CLB/DES or G/S active you can pull the heading knob and immediately after confirm the automatic change to OP CLB or V/S by pulling the respective buttons to prevent the attention getter and mode flashing.

When abnormal conditions are encountered the flight director (FD) might fail and a red FD text is visible on the primary flight display (PFD). When the autopilot was active then it disconnects itself.

Conditions that can trigger a flight director failure (red FD):

1. You are flying manually and didn’t pitch for the speed target and flew into the overspeed regime
2. The pitch angle or bank angle exceed the normal operating range
3. During an RNV approach the aircraft descended below the minimum descent altitude. Automatic landing is not possible during an RNV approach and the guidance is no longer valid and the autopilot disconnects

• If the autopilot tripped off push the instinctive takeover-button on the side-stick to cancel the warning and to take manual control of the aircraft
• Check that the airspeed, pitch and bank angles are within normal operating range

When an ILS is flown with the LOC and G/S mode they combine to the LAND mode below 400 feet above the ground. When the localizer or glide slope signals are lost or when deviations become excessive or then the autopilot is turned off below 200 feet then a red AUTO LAND indicator flashes in the glareshield.

The automatic landing is no longer possible and the landing should be aborted unless you have the runway in sight and can take manual control.

• Take manual control if you have the runway in sight
• Otherwise perform a go-around by moving the thrust levers to TOGA

During cruise the navigation display displays the point at which you need to start descending (the top of descent, TOD) in form of a white arrow pointing down and right. That is the point at which the descent should be initiated. When you have flown past the top of descent point (TOD) then a white DECELERATE text is written on the primary flight display (PFD) reminding you that you should descent or slow down at least.

• Initiate the descent by selecting a lower altitude and pushing the altitude knob in or pulling it

Hint - The green dot on the altitude tape indicates the planned target altitude for the managed descent.

During the descent the flight management system computes the optimal vertical profile to meet all altitude constraints along the route. When the aircraft is too high and cannot descent in time for the next altitude constraint then a “MORE DRAG” message is shown to the pilot.

• Extend the speedbrake to descent quicker

Hint - On the navigation display a blue saw-tooth arrow points at the location where the vertical profile will be intercepted with half deflected speedbrakes.

The altitude alert is a continuous chime that plays a C-Chord note and flashes the altitude window on the primary flight display. The alert is triggered when the aircraft has not levelled off at the selected altitude and has flown through it or deviated from the selected altitude after a while. This alert is designed to get the attention of the pilots to monitor their altitude.

Reasons why this happens

1. You are in a steep descent and select an altitude very close to the current altitude. The altitude capture mode engages but the aircraft cannot pitch down in time with the maximum vertical g-load limits and overshoots the target altitude
2. You are flying manually and did not level off at the selected altitude or deviated after capturing it

• Push the master caution button to mute the altitude alert sound
• Fly back to the selected altitude or change the selected altitude

Note - A brief (about one second) c-chord can be heard and the altitude window flashes in yellow when you are approaching the target altitude and the autopilot is not flying. This is a reminder for the pilots to start leveling off now

When climbing to the cruising altitude you should switch to the standard pressure setting when passing through the transition altitude of the departure airport. Similarly during the descent you should switch back to local QNH pressure setting when you are descending through the transition level on the way to your destination airport.

When you have not switched to STD pressure setting above the transition altitude during climb the pressure setting starts flashing.

• Pull the pressure setting knob on the EFIS control panel to set standard pressure barometric reference (Std)

During the descent when you have not switched back to QNH below the transition level the pressure setting also starts flashing.

• Push the pressure setting knob on the EFIS control panel to set QNH barometric reference
• Rotate the pressure setting knob to set the local pressure setting

Hint - In the U.S. the transition altitude and transition level are 18,000ft but in Europe these values change depending on the weather and airport surroundings. Naturally you can find higher transition altitudes near mountainous terrain where it is important that aircraft know the correct height relative to mountains in the area.

When flying with autopilot engaged the maximum speedbrake deflection on the A320 is reduced to increase passenger comfort, to increase stall margins and to reduce pitch trim wear. Most of the time the reduced deflection is enough to slow down or descent back to the target path. But in some cases you may need the maximum deflection possible.

• Turn on the seat-belt signs
• Disconnect the autopilot to use maximum speedbrake deflection

Airbus aircraft also have a build in spoiler protection. When the airspeed get’s too low the speedbrakes are automatically retracted and kept in the retracted position to increase the lift and to prevent a stall. They also retract automatically when the pilots add TOGA thrust.

When the speedbrake lever is not at the retracted position and the speedbrakes have been retracted automatically then the ECAM issues a master caution with the speed brake disagreement.

• Retract the speedbrake lever and wait at least 5 seconds for the system reset if you want to deploy them again

Each approach has a minimum altitude that you are allowed to descent to or a minimum height above the ground at which you are required to have visual contact with the runway or approach lighting system. The minimum descent altitude (MDA) is a barometric altitude entered in the MCDU and the decision height (DH) is a radar altitude value also entered in the MCDU.

When the aircraft descents below these minimum altitudes then the primary flight display shows a flashing “DH”.

• If you see the runway continue the approach, disconnect the autopilot if it’s not an ILS autoland
• If you cannot see the runway: perform a go-around by moving the thrust levers to TOGA

Approach markers are radio beacons with a limited range that are installed along the final approach course for a runway. The outer marker (OM), middle marker (MM) and inner marker (IM) are displayed in the lower right corner of the attitude indicator and blink or flash when the aircraft flies over it. This is an information for the pilot that they are approaching the runway.

If you know the approach markers are installed on a runway and are working then you can double-check the distance to the threshold with these approach markers.