A320 Managed vs Selected Modes — When to Push, When to Pull, and Why the Plane Ignores You

There is a moment every Airbus simmer has. You are at 8,000 feet, cleared to climb, you spin the altitude knob to FL340, and you push it. The aeroplane keeps flying straight and level as if you had not touched anything at all. So you push it again, harder, as though the FMGC were a lift button in a hurry.

The A320 is not ignoring you. It is refusing you, which is a different thing, and it has told you why on the FMA — you just have not learned to read the answer yet.

Almost every "why is it doing that" moment on an Airbus comes back to one question with two possible answers: whose number is the aeroplane flying, mine or the box's? Get that question and its four windows straight and the aircraft stops being mysterious. This guide is that mental model, applied across speed, heading and altitude together.

The One Rule

Every knob on the FCU does the same three things, and they never change meaning between knobs:

• Push — hand the target to the FMGS. This is managed mode. The FlyByWire documentation puts it as plainly as it can be put: push to "let the FMGS manage the corresponding mode".
• Pull — take the target yourself. This is selected mode: "use the flight crew selected value for the corresponding mode".
• Turn — change the number, for whichever of the two is currently in charge.

That is the whole convention. Managed modes "are activated when the corresponding knob on the FCU is pushed in"; selected modes "are activated by pulling the corresponding knob in the FCU". Speed, heading, altitude, vertical speed — same grammar, four times.

The mental shorthand that makes it stick: push the knob in and the target goes into the aeroplane. Pull it out and the target comes out to you.

Boeing pilots coming across find this alien mostly because Boeing splits the same idea across separate buttons — LNAV, VNAV, HDG SEL — where Airbus overloads one knob per axis with a push/pull axis of its own. If you are switching between the two types regularly, the A320 vs 737 comparison covers where else the philosophies diverge.

Dots, Dashes, and the One Window That Lies

You can read who owns each axis without touching anything, straight off the FCU.

In managed mode, a window "shows 3 dashes and a dot to the right". In selected mode, "the display shows the selected value and no dot". Dashes mean the aircraft has a target you cannot see from here — it lives in the MCDU. A number means you put it there.

So the healthy cruise picture is dashes and dots in the speed and heading windows, because the FMGS is flying its own speed schedule along its own route.

And then there is the altitude window, which is the exception that catches everyone. Per the same documentation: "The altitude window always displays an altitude selected by the pilot and never dashes. The dot signifies managed altitude."

Read that twice, because it is the single most common misread on the flight deck. The altitude window always shows a number. That number is not evidence of anything. It is your cleared altitude, and you set it whether you are in managed climb or open climb or vertical speed. The only thing that tells you who owns the vertical path is the dot — and, definitively, the FMA.

This is why simmers fly entire sectors in selected modes without noticing. Speed and heading windows announce their state loudly by going blank. The altitude window looks identical in both, so a pull you made forty minutes ago is still in force and nothing on the FCU is shouting about it.

One more piece of FCU trivia worth knowing because it saves a lot of spinning: the outer ring of the ALT knob "switches the step-size of the inner knob from 100 to 1000 and vice versa".

A Short FMA Primer (Because the FCU Is Not the Answer)

The FCU shows what you asked for. The FMA — the lines across the top of the PFD — shows what the aircraft is actually doing. When those two disagree, the FMA is right and you are wrong. FlyByWire's documentation is unusually blunt about this: "The FMA always show the actual state of autoflight and should always be the main reference for pilots in regard to autoflight."

It has five columns, left to right:

1. Autothrust mode — THR CLB, THR IDLE, SPEED, MACH, and so on.
2. Vertical mode — CLB, DES, OP CLB, OP DES, ALT, ALT CST, V/S, G/S.
3. Lateral mode — NAV, HDG, TRK, LOC, RWY, APP NAV, GA TRK.
4. Approach capability — CAT 1, CAT 3 DUAL and friends.
5. AP / FD / A-THR engagement — what is actually switched on.

Two colours carry almost all the information. Green means engaged right now. Cyan (blue) means armed — the mode is queued and will engage when its conditions are met. NAV, for example, is "displayed in green when NAV mode is engaged" and "displayed in blue when NAV mode is armed". And when anything changes, you get a "white box around the new annunciation for 10 seconds" — the aircraft flagging its own mode change so you cannot miss it.

Columns two and three are your push/pull scoreboard. If column three says HDG, your lateral target is yours. If it says NAV, it is the box's. There is no ambiguity and no need to guess.

That is as much FMA as this guide needs. The discipline it buys you is simple and non-negotiable: after every push or pull, look up and confirm what changed. Not the FCU — the FMA.

Managed Speed: Where the Magenta Number Actually Comes From

"Managed speed" is not one speed. It is a schedule, and the FMGS picks whichever element of that schedule applies right now. With NAV engaged, the profile runs in this order:

"V2, SPD LIM, SPD CSTR (if applicable), ECON CLB SPD/MACH, ECON CRZ MACH, ECON or preset DES MACH/SPD, SPD LIM, SPD CSTR (if applicable), HOLD SPD (if applicable), VAPP."

Unpacked, there are four sources feeding that:

ECON speed comes from the cost index you typed on INIT A, combined with aircraft weight. Low cost index means slow and efficient; high means fast and thirsty. It is why cost index is not a decorative field — it is the number that decides your cruise Mach and both your climb and descent speeds. You can watch it move the schedule directly in the cost index experiment in our free browser MCDU trainer.

SPD LIM is the low-altitude speed limit. In managed climb below the transition it is what puts you at 250 kt — FlyByWire's own FCU example describes the managed window as meaning "250 kt below 10 000 ft, 290 kt above". Worth knowing where that limit comes from, though: it "can be either a system default, a NAV database airport default, or a pilot entry", so do not assume 250/10000 is universal. Check the PERF page rather than trusting the habit.

SPD CSTR are the speed constraints attached to individual waypoints by your SID or STAR, or typed in yourself on a vertical revision. The F-PLN page grades its own homework here: a magenta asterisk means the FMGS predicts it will make the constraint (altitude within 250 ft, speed not more than 10 kt above), an amber asterisk means it predicts a miss. Learn to scan that column. Building and reading those constraints is exactly what the VERT REV constraints scenario drills.

The PERF phase decides which of the above is even in play. Press PERF and "the page for the currently active phase is brought up" — so the page you land on tells you what phase the aircraft thinks it is in. Each of those pages carries an ACT MODE field that "displays the preselected or active speed mode: SELECTED or MANAGED" and cannot be edited from there. It is a read-out, not a control — a second opinion on the FCU dot, from the other side of the cockpit.

Click to expand PERF CLB with 230 kt entered as a preselected speed: ACT MODE now reads SELECTED, while the managed target is still listed on the MANAGED line. Rendered by our own A320 MCDU trainer.

The rule that surprises people

Here is the connection almost nobody makes until it bites them:

"Managed speed accounts for all speed constraints in the flight plan when the lateral navigation NAV is enabled. Otherwise, any speed constraints are ignored."

Your speed constraints only exist while NAV is engaged. Take a radar vector, pull the heading knob, and your carefully-entered 210 kt at the initial approach fix quietly stops applying — even though the speed window still shows dashes and a dot, and even though the constraint is still sitting there on the F-PLN page. Managed speed keeps running, just on the shorter profile: V2, SPD LIM, ECON, SPD LIM, VAPP.

The lateral mode is not a separate concern from the speed mode. Pulling one knob changes what a different knob means.

NAV vs HDG: What Arms and What Engages

Laterally the choice is straightforward. NAV is managed — it flies the F-PLN. HDG (or TRK, depending on the FCU selector) is selected — it flies the number in the window.

NAV has exactly one precondition, and it is the obvious one: it "requires a valid flight plan defined in the MCDU". No flight plan, no NAV — the push does nothing at all, because there is nothing to navigate along.

NAV is also the standard example of arming. Before takeoff you set it up on the ground and it sits in the FMA in cyan, waiting; it goes green once airborne and the conditions are met. Armed is not engaged. A cyan NAV is a promise, not a state.

The trap is the reversion. When the aircraft reaches a discontinuity in the flight plan, "the NAV mode automatically reverts to the HDG (TRK) mode". Nobody pulled anything. The aeroplane demoted itself, because the route ran out. And the moment that happens you have silently lost your speed constraints too, per the rule above — one unnoticed discontinuity, two systems degraded.

Click to expand A discontinuity on the F-PLN page: EGLL to LFPG with only MID entered, and the route broken at the amber line. Reaching that line is what drops NAV into HDG.

Discontinuities are why "it just flew off on a heading" is such a common report, and closing them is a two-minute MCDU skill: work through it in the discontinuity scenario. If your lateral guidance is failing in ways that feel more fundamental than this, LNAV not working in MSFS covers the cross-platform causes.

Managed CLB and DES vs OP CLB and OP DES

Vertically you have two pairs, and the difference between them is one word: constraints.

Managed CLB and DES honour the altitude constraints in your flight plan. They fly the FMGS's vertical profile, levelling at crossing restrictions along the way — that is what the ALT CST annunciation means when it appears, the aircraft capturing a constraint altitude rather than your FCU altitude.

OP CLB and OP DES do not. They are pulled, not pushed, and "the OPEN DES mode disregards all altitude constraints" — as does OPEN CLB up to the FCU selected altitude. They climb or descend straight to the number in your window and ignore everything in between. That is not a fault; it is the point. When ATC says "climb FL200, disregard published restrictions", OP CLB is precisely the correct tool.

The thrust behaviour differs too. Open modes are the classic thrust-and-pitch arrangement: OP CLB uses climb thrust with pitch holding the speed, OP DES is an idle descent with pitch holding the speed. The managed modes are flying a computed path instead, which is a fundamentally different job.

The engagement conditions are where pushes get refused. For managed CLB, all of these must hold: airborne for more than 5 seconds, the FCU selected altitude above the current altitude, not in descent, approach or go-around phase, NAV engaged, and not in G/S mode.

For managed DES: the FCU altitude below the present altitude, "either NAV, LOC*, LOC are active", not in takeoff, climb or go-around phase, the "vertical flight path is valid", and not in TO, G/S, LAND, FINAL or GA mode.

Read those lists again and notice what they share. Both managed vertical modes require a managed lateral mode. There is no managed climb or descent while you are in HDG. If you are on a vector and you push the ALT knob expecting the aircraft to start down its profile, it will decline — correctly — because there is no lateral path for a vertical path to sit on top of.

And "the vertical flight path is valid" is doing quiet work in that list. A flight plan that ends at an airport with no arrival, or one broken by a discontinuity, may not give the FMGC enough to build a descent path from. No path, no managed descent, no matter how hard you push.

Managed descent is deep enough to deserve its own treatment — the idle and geometric segments, the vertical deviation donut, being high and getting back down. Our A320 managed descent guide goes through DES and OP DES specifically. This guide stops at the push/pull boundary.

The Traps

Stuck in selected without noticing

The most common one, and the reason for the altitude-window warning above. You pull the speed knob for one ATC restriction, deal with it, and never push it back. Twenty minutes later you are wondering why the aircraft is not slowing down for the STAR. It is doing exactly what you told it to and has not changed its mind since.

There is a real fix and it is the FMA discipline: after every intervention, plan the return to managed. A pull is a loan, not a transfer.

The V/S trap

V/S is the most dangerous knob on the FCU precisely because it is the most obedient. It is a pitch mode — the elevator holds the vertical speed you asked for, and "the corresponding A/THR mode is SPEED or MACH", meaning the autothrust is left to chase the speed with whatever thrust it has.

Follow that through. If you demand a climb rate the engines cannot support at that altitude, the aircraft still holds the vertical speed, because that is what you asked for. The thrust runs out. Speed is the variable that gives. Managed and open climb modes cannot do this to you — in those, pitch is holding speed and vertical rate is the variable — which is exactly why V/S is a tool for small, deliberate, monitored adjustments and not a way to fly a climb.

If you ever need out immediately, the escape is built into the same knob: push the V/S-FPA knob and "an immediate level off is commanded (V/S of 0)".

The baro knob inverts the rule

This one is genuinely cruel, and it is inches away on the same glareshield. On the EFIS control panel, the barometric reference knob also pushes and pulls — but pulling selects STD, and pushing recalls the last QNH or QFE setting.

That is the opposite polarity to everything you just learned. On the FCU, pull means my number. On the baro knob, pull means the standard datum and push gives you back the local one. There is no deeper logic to reconcile; they are simply different systems that happen to share a gesture. Just know that the muscle memory does not transfer, and set the baro deliberately rather than by feel.

It is the mouse, not the aeroplane

Before you diagnose an FMGS refusal, make sure the push ever reached the aircraft. On the MSFS forums, a March 2026 thread titled "Can't change between managed and selected mode in airbus" ran to seventeen replies before the cause turned out to be a broken mouse wheel button.

The default LOCK cockpit interaction mode needs more than a left click for a push or a pull: you left-click and hold to lock onto the knob, then trigger a second button. Those are two separate bindings, and it is worth knowing them by name rather than by button, because the defaults vary and can be remapped — look under Options for cockpit interaction secondary action (that is your push) and cockpit interaction tertiary action (that is your pull). On a common mouse they land on the right button and the scroll-wheel click. If you are missing either button, or the binding is unassigned, every push you make is imaginary. LEGACY mode is the simpler alternative — it puts a small arrow on the knob you can click directly.

Test it on the ground. Pull the speed knob and watch a number replace the dashes. If it does not, your problem is in Options, not in the MCDU.

No speed profile at all

The other forum thread behind this guide — "A320neo V2 managed speed vs selected speed — I am confused" — ended with a diagnosis worth memorising: the user's gross weight field was showing dashes.

The MCDU is explicit about this. "The crew must enter the ZFW/ZFWCG values to obtain a speed profile and predictions", and the gross weight "field displays dashes, as long as the system is not calculating the Fuel On Board, or ZFW has not been entered by the flight crew".

Click to expand FUEL PRED before the ZFW is entered: amber boxes ask for ZFW/ZFWCG, and GW/CG shows dashes. With this picture, managed speed has no weight to build a schedule from.

With no weight, there is no speed schedule for managed speed to fly. So the push is refused, and it looks like a bug. It is the aeroplane declining to invent numbers it does not have. If your managed speed will not engage, go to INIT B or FUEL PRED and look at GW before you look at anything else — and if you are hazy on the initialisation sequence generally, the A320 MCDU explained walks the pages in order.

Building the Habit

There is a rhythm that experienced Airbus pilots run without thinking about it, and it is only three beats:

1. Decide whose number this should be. Is this something ATC just told me (mine, pull), or something my flight plan already knows (the box's, push)?
2. Push or pull, then read the FMA. Not the FCU. Confirm the mode you wanted is green, and note anything sitting in cyan waiting to engage.
3. Plan the way back. If you pulled, know what has to happen before you push again — and know what you lost in the meantime. A pull on the heading knob costs you your speed constraints as well as your lateral path.

The reason so much of this guide keeps pointing at the MCDU is that managed targets do not originate on the FCU at all. The FCU is a switch that says "use the box's number". Which number the box offers was decided by the cost index on INIT A, the ZFW on INIT B, the constraints on the F-PLN, and the phase pages under PERF. Push the knob and the FMGS gives you what it was told. If that turns out to be the wrong speed or the wrong path, the mistake was typed in earlier.

So the fastest way to get good at push and pull is to get good at the pages the pushes reach. All of these run in the browser, free, no simulator and no add-on required:

• Performance Init — the PERF pages that every managed speed target is read from.
• Cost Index Experiment — change one number, watch the whole ECON schedule move.
• Constraints in VERT REV — hang speed and altitude restrictions where managed modes will honour them.
• Closing a Discontinuity — repair the break that silently drops NAV into HDG.
• Descent Setup — the crossing constraint that makes a managed descent possible in the first place.

Then go and fly a sector deliberately. Every time you touch the FCU, say out loud which mode you are asking for and read the FMA to check you got it. It feels laborious for about two flights, and then it disappears into the background and the aeroplane stops surprising you.

For the wider autopilot picture across aircraft types, see our MSFS 2024 autopilot guide; if your vertical guidance is failing outright rather than merely confusing you, start with VNAV not working in MSFS 2024.