Step Climb Mid-Cruise

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📍 Route: EGLL → KJFK⏱ ~5 minutes📊 6 steps🎓 Enroute Operations

Mid-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; the new cruise level is entered on INIT.

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.

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.

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Step-by-step: Step Climb Mid-Cruise

  1. Set up the long-haul cruise. Type EGLL/KJFK and press 1R to enter your route.

    Eastbound and westbound transatlantic flights typically step climb 1-2 times during the cruise. As fuel burns off, the aircraft's optimum altitude rises — flying at the optimum saves fuel directly. The OFP usually pre-plans these step climbs, but you have to execute them by changing CRZ FL when ATC clears the new level.

  2. Set the flight number BAW117. Type BAW117 and press 3L.
  3. Set initial cruise level FL340. Type 340 and press 6L.

    Semi-circular rules: westbound (track 180-359°) uses even levels, eastbound (000-179°) uses odd. Heavy aircraft can't reach their optimum altitude immediately — at takeoff weight, FL340 may be the highest practical level. As fuel burns the optimum rises by ~1,000-2,000 ft per hour of cruise.

  4. Two hours into the cruise, you've burned enough fuel to step up. Open the PROG page to see the recommended maximum altitude.

    PROG is the in-flight situational page. The REC MAX value (here shown as FL398) is the absolute ceiling for the current weight. OPTimum is usually 2,000-4,000 ft below REC MAX. You always step up to a level below REC MAX to leave margin for turbulence and weight uncertainty.

  5. Return to the INIT page to update the cruise level.
  6. Step up to FL360. Type 360 and press 6L to update CRZ FL.

    After updating CRZ FL the FMS recalculates the rest of the cruise at the new altitude. Real Airbus pilots cross-check the new fuel prediction against the OFP step-climb plan before accepting. If predicted arrival fuel is below reserves, you don't step 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; INIT is where the new level is entered.
  • 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

Background reading

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