Learn when to activate the A320 Approach Phase, how DECEL triggers it automatically, when to use the MCDU manually, and common timing mistakes.
Activate the Airbus A320 Approach Phase when you are ready to begin the final deceleration and configuration sequence—normally automatically as the aircraft passes the flight plan’s DECEL point in managed NAV. Activate it manually if radar vectors, a shortcut or selected heading will prevent DECEL from sequencing, or if you need to slow earlier.
In Aviation & Real-World Flying terms, this is an FMGS timing decision, not the act of arming approach guidance. Exact crew timing follows operator procedures and ATC instructions; in a simulator, the same logic is the best baseline, subject to how completely the aircraft add-on models the FMGS.
When does the A320 activate Approach Phase automatically?
The FMGS normally activates Approach Phase when the aircraft sequences the flight plan’s DECEL pseudo-waypoint while following the active route in NAV mode. DECEL is positioned to provide room for the planned deceleration towards the approach and landing configuration.
It is not tied to one universal altitude or distance from the runway. Its position depends on the programmed route and approach, so an incomplete arrival, route discontinuity or missing approach can make it absent or unsuitable. Check how to programme the A320 MCDU arrival and approach data if the DECEL point does not appear where expected.
| Situation | Recommended action |
|---|---|
| NAV mode is following the planned route and DECEL is ahead | Allow automatic activation at DECEL. |
| ATC vectors you in HDG/TRK before DECEL | Activate manually when ready to start the approach deceleration. |
| A direct-to or shortcut bypasses DECEL | Activate manually based on the remaining track miles and energy state. |
| ATC requires a higher speed after activation | Leave Approach Phase active and use selected speed until released from the restriction. |
| No DECEL point is displayed | Check the flight plan, then use manual activation at the appropriate point. |
How do I activate Approach Phase manually?
Manual activation is performed on the MCDU PERF APPR page when the aircraft needs to begin its approach-speed schedule without sequencing DECEL.
- Prepare the approach. Confirm the runway and approach, remove unintended discontinuities, and enter the required PERF APPR data such as QNH, temperature, wind and minima.
- Choose the right moment. Use remaining track miles and the aircraft’s energy state, not merely the fact that ATC has cleared you for the approach. A clearance issued far from the airport does not by itself require immediate activation.
- Open the APPR performance page. Press
PERF, display theAPPRpage—using the next-phase prompt if required—and selectACTIVATE APPR PHASE. Confirm the selection if the MCDU presents a confirmation line. - Verify the result. Check that the activation prompt has gone and that the managed-speed target now follows the approach schedule. If selected speed is in use, it will continue to control until managed speed is re-engaged.
MCDU page layout and confirmation behaviour can differ slightly between simulated A320 implementations, but the underlying decision and flight-phase logic should be the same.
What does Approach Phase actually change?
Approach Phase changes the FMGS flight phase and enables the managed approach-speed schedule. In managed speed, the target progresses through the relevant green-dot, S and F manoeuvring references and ultimately towards VAPP as the aircraft is configured for landing.
Activation does not extend the flaps, lower the landing gear, arm an ILS, capture the glideslope or make the aircraft descend. The pilot must still manage configuration, guidance and energy.
Is Approach Phase the same as the FCU APPR button?
No: MCDU Approach Phase controls flight-phase and managed-speed logic, while the FCU APPR button arms the appropriate lateral and vertical approach guidance.
- MCDU Approach Phase: activates the approach-speed schedule and related FMGS predictions.
- FCU APPR button: typically arms localiser and glideslope modes for an ILS, or the applicable managed guidance for a supported non-precision approach.
Pressing the FCU button does not activate the MCDU phase, and activating the MCDU phase does not arm approach guidance. Our explanations of A320 FCU modes and indications cover the mode controls, while the worked A320 ILS approach sequence shows where both actions fit during an arrival.
Why did Approach Phase not activate at DECEL?
Most apparent failures occur because DECEL was not actually sequenced or because selected speed conceals the managed-speed change.
- The aircraft was being vectored in selected HDG/TRK rather than following the active route in NAV.
- A direct-to, shortcut or flight-plan edit placed DECEL behind the aircraft or removed it from the route.
- A route discontinuity prevented normal waypoint sequencing.
- Approach Phase is active, but the FCU remains in selected speed, so no automatic deceleration is visible.
- The simulated aircraft has limited FMGS modelling and does not reproduce automatic phase activation faithfully.
Check the PERF page and active flight plan before repeatedly pressing the FCU APPR button; that button cannot correct a missed MCDU phase change.
What if I activate it too early or too late?
An early activation can normally be managed with selected speed, while late activation requires prompt correction and an honest assessment of whether enough distance remains for a stabilised approach.
What should I do after activating too early?
Select the required speed and continue with Approach Phase active, then return to managed speed when appropriate. FMGS flight phases are intended to advance in sequence, so do not expect to restore the previous descent phase after confirming activation.
What should I do after activating too late?
Activate Approach Phase manually, use an appropriate selected speed if faster deceleration is needed, and configure only within the aircraft’s speed limits. Use speed brakes only as permitted by the applicable procedure. If the aircraft cannot meet the required stabilised-approach criteria, the correct response is a go-around rather than rushed flap or gear extension.