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.
What this scenario covers
A step climb is a cruise-level change taken as weight decreases. The optimum altitude for a jet rises as it gets lighter, so the flight that departed unable to make FL360 can make it comfortably two hours later. The PROG page shows the recommended maximum and optimum, and it is also where the new cruise level goes in — INIT is a preflight page, and by the top of climb it is behind you.
The scenario is a check-then-act sequence: read what the aircraft says it can do, then commit the level change. The order matters — asking for a level the aircraft cannot hold is how you end up at cruise thrust and decaying speed.
It is also the one exercise in the A320 set that runs in a declared cruise phase rather than on the stand, so the PERF key opens CRZ instead of TAKE OFF and the pages for the flown climb are gone. That is the FMGS behaving as it does in flight, not a restriction of the trainer.
How it applies in flight ops
On the North Atlantic Track system, step climbs are planned into the flight plan and requested from oceanic control at specific points. Getting the step is worth real money in fuel, which is why dispatchers plan for it and crews chase it.
The limiting factor is buffet margin, not thrust alone. MAX REC on PROG already accounts for it, which is why crews treat that figure as the ceiling rather than working it out from first principles at three in the morning.
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: Step Climb Mid-Cruise
- Press PERF. Note which page opens.
The PERF key is phase-sensitive on the real MCDU: it always opens the page for the active flight phase. On the ground that is TAKE OFF; in the cruise it is CRZ. This is worth feeling once, because it is the fastest way to confirm what phase the FMGS thinks you are in when something is not behaving.
- Look ahead at the descent. Press 6R (NEXT PHASE) to step forward to PERF DES.
Crews routinely brief the descent from the cruise, so the chain always lets you walk forward. What it will not do is let you walk back past the phase you are in.
- Come back to the cruise page. Press 6L (PREV PHASE).
On PERF CRZ there is no PREV PHASE prompt at all — the climb is flown, and the FMGS does not offer pages for flown phases. It is not drawn rather than drawn-and-refusing, which is the Airbus convention: a prompt on the screen is a promise that the key does something.
- Open PROG to see the recommended maximum altitude.
REC MAX (here FL398) is the ceiling for the current weight, and it accounts for buffet margin, not just thrust. OPT is usually 2,000–4,000 ft below it. You step up to a level below REC MAX to leave margin for turbulence and weight uncertainty.
- Take the step. Type 360 and press 1L to enter the new cruise level.
Westbound tracks use even levels, so FL340 steps to FL360. On the North Atlantic the step is planned into the OFP and requested from oceanic control at a specific point, rather than taken when it suits. Real crews cross-check the new arrival-fuel prediction against the plan before accepting a step — if it puts arrival fuel below reserves, you do not go up, even if ATC offers it.
What to take away
- Optimum altitude rises as fuel burns off — the step climb is how you collect it.
- PROG shows recommended maximum and optimum, and takes the new cruise level in flight.
- The PERF key opens the page for the phase you are in — CRZ in the cruise, not TAKE OFF.
- Check before you climb: a level above MAX REC cannot be held.
- On oceanic tracks the step is planned in advance and requested, not taken.
The rest of Enroute Operations
ATC 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
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📍 EGLL → LFPG, then divert to EGLL → EBBR⏱ ~4 min📊 8 stepsSpeed & 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.
📍 EGLL → DVR → LFPG⏱ ~4 min📊 5 stepsEntering a Holding Pattern (HOLD)
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📍 HOLD AT LFPG⏱ ~4 min📊 6 steps
Background reading
- GuideFlying Long-Haul in MSFS 2024: The Complete Guide from Planning to Parking
Fly a full long-haul in MSFS 2024 in the PMDG 777 — SimBrief planning, North Atlantic Track procedures, step climbs, fuel and descent planning.
- 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.
- GuideA320 vs 737 in Flight Sim: Which Should You Fly?
A320 vs 737 in MSFS and X-Plane — fly-by-wire vs conventional, which addons get each right, the cost, and which airliner is more fun to fly.