Mid-Cruise Fuel Check (PROGRESS)
PremiumintermediateThirty minutes into the sector the FMC has lost its fuel quantity data: read the predicted destination fuel on PROGRESS, then give the FMC the fuel on board by hand.
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.
Normally nobody types fuel in flight: the FMC takes the fuel on board straight from the fuel quantity system. The exception is the one this scenario practises. When the FMC stops receiving fuel data, PERF INIT shows dashes and takes a manual entry, which the FCOM says to repeat about every 30 minutes to keep gross weight current. The second half of the scenario makes that entry from the gauges, and the gross weight with it.
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
The CDU checks 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 predicts the fuel remaining at the destination from the fuel on board minus the predicted burn. PROGRESS is read-only. Normally the fuel on board comes straight from the fuel quantity system and nobody types it; when it has to be entered by hand, that happens on PERF INIT, and PROGRESS then re-computes.
- Open PERF INIT to enter the fuel on board by hand.
On a normal flight there is nothing to enter here: "Fuel on board is automatically displayed as received from the airplane fuel quantity indication system" (FCOM 11.40.26), so the FMC and the fuel gauges agree by design. This flight is the exception the FCOM describes: "In flight, when the FMC is not receiving the required fuel data, the CDU displays dashes and allows manual entry of fuel weight." The fuel gauges on the overhead still work and read 4.0 t, so that is the figure the FMC needs from you.
- Enter the fuel on board from the gauges, 4.0 tonnes. Type 4.0 and press 2L.
On the aircraft, "After manual entry, MAN (manual) appears next to the fuel weight" (FCOM 11.40.26); this trainer does not draw the MAN label. The entry is not a one-off either: "Manual entry of fuel weight should continue approximately every 30 minutes for the remainder of the flight to keep gross weight current." Each entry triggers a fresh prediction on PROGRESS, and each one is followed by a re-check on PROG 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 + 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. On the aircraft the FMC works gross weight out itself from the ZFW and the fuel figure, which is why the FCOM ties the manual fuel entry to keeping "gross weight current". This drill starts with no ZFW in the trainer, so it cannot do that sum, and it asks you to enter the weight yourself.
- 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.
- Fuel on board comes from the fuel quantity system; it is typed only when the FMC loses that data.
- 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
- 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.
- 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.