Mid-Cruise Fuel Check (PROGRESS)
PremiumintermediateThirty minutes into the sector: read the predicted destination fuel on PROGRESS, then reconcile PERF INIT against what the gauges actually say.
What this scenario covers
PROGRESS is the in-flight status page — distance and time to the next waypoint and the destination, and the predicted fuel remaining on arrival. It is the page a fuel check is read from.
The second half of the scenario updates PERF INIT with the current fuel on board and gross weight against the fuel quantity indication, so the FMC is predicting from reality rather than from the gate figures.
How it applies in flight ops
Airline SOPs require periodic fuel checks — commonly at every waypoint or on a fixed interval — comparing actual against planned. What is being watched is the trend: a small deficit that grows is a problem long before the absolute number looks alarming.
Discrepancies have prosaic explanations: a cruise level below plan, stronger headwinds than forecast, anti-ice running, or a plan built on the wrong weight. Each one is fixable if it is found early.
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 CDU validates every entry as you make it, and tells you when an entry was accepted but wrong.
Step-by-step: Mid-Cruise Fuel Check (PROGRESS)
- Open the PROGRESS page to see the predicted destination fuel.
PROGRESS is your in-flight fuel-monitoring page. It computes EFOB (estimated fuel on board) at the destination from current FOB minus predicted burn. Boeing keeps PROGRESS read-only — FOB and reserves are updated on PERF INIT, then PROGRESS re-computes.
- Open PERF INIT to update the fuel state to match the FQI.
The Fuel Quantity Indicator on the overhead now reads 4.0 t — different from what the FMC originally calculated. Discrepancies happen: fuel temperature, gauge tolerance, taxi-fuel variance, or non-standard winds in the climb. Crew updates PERF INIT to bring the FMC back in sync with the airframe.
- Update FUEL on board to 4.0 tonnes (current FQI reading). Type 4.0 and press 2L.
FUEL is FOB — what the gauges show right now. Updating it triggers a fresh EFOB calculation on PROGRESS. Underline this: every fuel discrepancy you find on a long leg becomes a manual update here, then a re-check on PROG, then a comparison against the flight’s reserves. Careful with the words here: MIN DEST FOB is an Airbus field and the 737 has no such thing. The Boeing equivalent is RESERVES on PERF INIT, and it is the FMC’s own trigger — predicted fuel at destination below RESERVES shows USING RSV FUEL on the CDU.
- Update Gross Weight to 62.2 tonnes (ZFW 58.2 + new FUEL 4.0). Type 62.2 and press 1L.
Gross weight (GW, the first half of the GW/CRZ CG pair on 1L) is the FMC's reference for performance — V-speeds, OPT/MAX altitude, descent path. After the FOB update it's out of date until you adjust GW too. Some FMC revisions auto-update GW when FUEL changes; the trainer asks you to update explicitly so you see the linkage.
- Return to PROGRESS and read the DEST row’s FUEL figure against the flight’s reserves.
The DEST row now predicts about 1.5 t at destination (FOB 4.0 − ~2.5 t remaining burn). On the 737 that column is just labelled FUEL — predicted fuel remaining at the destination (§11.41.17). Now compare it with the 2.0 t of RESERVES this flight was planned with, and read the answer honestly: 1.5 is BELOW 2.0. This is not tight, it is a flight that will arrive into its reserves, and the FMC says so — USING RSV FUEL on the CDU (§11.32.3). The decision it forces is a diversion or a request for a shorter routing, taken now while there is still fuel to take it with. That is what the mid-cruise check is for.
What to take away
- PROGRESS carries the predicted fuel at destination — the fuel-check number.
- Reconcile FOB and gross weight against the gauges, not the paperwork.
- Watch the trend across checks, not a single reading.
- Level, wind, configuration and a wrong initial weight are the usual causes.
The rest of Performance & Fuel
Pre-Flight Fuel Planning (PERF INIT)
PremiumintermediateAt the gate with the OFP for a Geneva sector: weights and fuel on PERF INIT, on one page where the Airbus uses two.
📍 EGLL → LSGG — pre-flight planning⏱ ~5 min📊 7 stepsTAKEOFF REF — V-speeds
PremiumintermediateTakeoff flap and V-speeds on the TAKEOFF REF page — the three numbers that turn a runway analysis into a takeoff you can fly.
📍 LEMD → EGLL⏱ ~3 min📊 6 stepsAssumed Temperature — Reduced Thrust Takeoff
PremiumbeginnerReduced-thrust takeoff, Boeing's way: the assumed temperature method. Tell the engines it is hotter than it is and they produce less thrust.
📍 LOWW → EDDM⏱ ~3 min📊 5 stepsCost Index — What Does It Do?
PremiumbeginnerThree cost index values on PERF INIT — 0, 30 and 80 — and the speed schedule changes under you.
📍 LIRF → LEMD⏱ ~3 min📊 5 steps
Background reading
- GuideThe Boeing 737 CDU / FMC Explained: Every Page
What is the 737 CDU and FMC? A plain-English guide to every Boeing 737 CDU page plus the EXEC/MOD workflow. Practice free in our CDU trainer.
- GuidePMDG 737 FMC Tutorial: Program Your First Flight Plan Step by Step
Program the PMDG 737 FMC from scratch: IDENT, POS INIT, ROUTE, PERF INIT, takeoff speeds, and VNAV setup. Every CDU page explained with the exact inputs.
- Guide737 FMC Constraints — 250B/, 10000A, and Every LEGS-Page Format That Actually Works
Every 737 CDU constraint format that works: A and B suffixes, speed/altitude pairs, the trailing slash rule, windows, DELETE, and why entries get rejected.