Speed & Altitude Constraints (VERT REV)
PremiumintermediateATC wants you at an altitude by a waypoint. The vertical revision page is where that promise gets written into the flight plan.
What this scenario covers
A vertical revision is opened by right-selecting a waypoint on the F-PLN page. It carries the vertical data for that point: altitude constraints, speed constraints, and the wind and step information the FMGS uses to build its profile.
Entering a crossing altitude there does more than annotate the display. The FMGS re-plans the vertical path so that the profile actually meets the constraint, which is what makes managed descent able to fly it.
How it applies in flight ops
Crossing restrictions are the currency of arrival management — "cross ABCDE at or below FL100 at 250 knots" is a normal instruction into any busy terminal area. Typing it into the box means the aeroplane will plan for it rather than the crew flying it by hand and hoping.
It is also a trap worth respecting. A constraint the aircraft cannot make is shown as unable, and crews are expected to notice and tell ATC rather than discover it at the fix. The FMGS will tell you; it will not negotiate for you.
Fly this one with Premium
Everything about this scenario is on this page, steps included — reading it costs nothing and always will. What Premium adds is doing it: the MCDU validates every entry as you make it, tells you when an entry was accepted but wrong, and saves your progress across devices.
Step-by-step: Speed & Altitude Constraints (VERT REV)
- Enter a route. Type EGLL/LFPG into the scratchpad and press 1R.
This seeds a route with a discontinuity between EGLL and LFPG — we will close it with a waypoint, then put a constraint on that waypoint.
- Press F-PLN to open the flight plan.
Constraints are entered per waypoint on the flight plan, so we work from the F-PLN page.
- Close the gap so there is a waypoint to constrain. Type DVR into the scratchpad and press 2L (the discontinuity line).
DVR (Dover VOR) is now an enroute waypoint between EGLL and LFPG — exactly the kind of point you would cross at a charted altitude.
- Open the vertical revision for DVR. Press 2R — the RIGHT line key next to DVR.
On the real A320, a LEFT line-select opens LAT REV (lateral — routing); a RIGHT line-select opens VERT REV (vertical — speed and altitude). This is the page where crossing constraints live.
- Enter a crossing altitude. Type FL100 into the scratchpad and press 1R (ALT CSTR).
ALT CSTR FL100 tells the FMGS to cross DVR at 10,000 ft. It now feeds the descent/climb profile and the predictions. A constraint shown in magenta is one the FMGS predicts it will meet; an amber one would warn it expects to miss it — which you fix by managing the energy state (speed/speedbrake), not by retyping the altitude.
What to take away
- Right-select a waypoint on F-PLN to open its vertical revision.
- Altitude and speed constraints entered there reshape the computed descent path.
- Managed descent flies constraints; it cannot fly the ones you never entered.
- If the profile says unable, that is a call to ATC, not a number to overwrite.
The rest of Enroute Operations
Step Climb Mid-Cruise
PremiumadvancedMid-Atlantic at FL340, hours of fuel burnt off, and the aircraft can now fly higher and cheaper. Check the maximum, then step up.
📍 EGLL → KJFK⏱ ~5 min📊 6 stepsATC Shortcut: Going Direct
Premiumintermediate"Direct OCK" — five seconds of radio and a chunk of your flight plan gone. On this FMS the keypress is the commitment: there is nothing to confirm and nothing to undo.
📍 EGLL approach — direct routing⏱ ~4 min📊 5 stepsDiversion to Alternate
PremiumintermediateMid-planning, ATC sends you to Brussels instead of Paris. Rebuild the flight around a new destination without unpicking the whole thing.
📍 EGLL → LFPG, then divert to EGLL → EBBR⏱ ~4 min📊 8 stepsEntering a Holding Pattern (HOLD)
PremiumintermediateHolding is not a manoeuvre you fly from memory on an airliner — you build it in the box. Here is where the HOLD page hides and what it wants.
📍 HOLD AT LFPG⏱ ~4 min📊 6 steps
Background reading
- GuideWhy VNAV Doesn't Work When You Turn On the Autopilot
VNAV won't engage or won't descend in MSFS 2024? The 6 most common causes on the PMDG 737 and Airbus A320 — and exactly how to fix each one.
- GuideThe A320 MCDU Explained: Every Page, Simply
What is the A320 MCDU? A plain-English guide to every Airbus MCDU page — INIT, F-PLN, PERF, RAD NAV and more. Practice free in our MCDU trainer.
- GuideMastering VNAV Descent: Stop Arriving Too High and Too Fast
How VNAV descent works in the PMDG 737 and Airbus A320 — PATH vs SPD, managed descent, altitude constraints, and how to recover when you're too high.