Mid-Cruise Fuel Check (FUEL PRED)
PremiumintermediateThirty minutes into a Heathrow–Geneva sector, the fuel check: what the tanks actually hold against what the plan said they would.
What this scenario covers
FUEL PRED is the in-flight face of the fuel planning entered before departure. It shows fuel on board, the predicted fuel at destination and at the alternate, and the margin against the reserves — all recomputed continuously against the actual burn.
The scenario updates the page with the current weights and fuel state and then compares against plan. That comparison is the entire point: the number matters much less than the trend it is on.
How it applies in flight ops
Airline SOPs mandate a fuel check at regular intervals, typically at each waypoint or every thirty minutes. The crew compares actual fuel against the plan figure for that point, and a growing negative difference is investigated long before it becomes a reserve problem.
The causes of a drift are mundane and diagnosable — a level below plan, a stronger headwind than forecast, an engine anti-ice selection left on. Catching it at the first check gives hours to act; catching it on descent gives minutes.
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: Mid-Cruise Fuel Check (FUEL PRED)
- Press the FUEL PRED key to open the fuel prediction page.
FUEL PRED is your mid-flight fuel monitoring page. The FMS computes EFOB (estimated fuel on board) at destination and alternate, and warns you if either falls below the regulatory minima. Garbage in, garbage out — the page is only useful if ZFW, FOB, and reserves are kept current.
- Enter ZFW/ZFWCG. Type 62.5/27.0 and press 3R.
ZFW is Zero Fuel Weight — the aircraft, crew, passengers, and cargo, but no fuel. ZFWCG is the longitudinal centre of gravity at that weight, expressed as a percentage of the Mean Aerodynamic Chord. For a typical short-haul A320 load, 62.5 t and 27% MAC are normal; the FMS uses both to build accurate trip fuel and trim predictions.
- Enter Fuel On Board. The fuel page shows 8.5 t. Type 8.5 and press 4R.
FOB is your actual fuel right now, read from the FQI (Fuel Quantity Indicator). The FMS combines FOB with current GW and route distance to compute EFOB at destination. Always update this against the FQI — fuel can leak, transfer, or simply burn faster than predicted in turbulence.
- Enter route reserve. Type 0.2/5.0 and press 3L.
Route reserve (also called contingency fuel) is the buffer for unforeseen events: stronger headwinds, ATC routing changes, or holding. The 5% percentage is the ICAO/EASA regulatory baseline against trip fuel. For a ~3.8 t short-haul trip, 5% ≈ 0.2 t. Some operators use 3% with statistical fuel, but 5% is the safe textbook answer.
- Enter final reserve. Type 1.1/0030 and press 5L.
Final reserve is the fuel you must land with regardless of conditions. ICAO/EASA require 30 minutes holding at 1500 ft above the alternate. For an A320 at light landing weight, that's ~1.1 t. The HHMM field is the duration: 0030 = 30 minutes. The FMS uses this as a hard floor in its EFOB warnings.
- Enter minimum destination FOB. Type 2.6 and press 6L.
MIN DEST FOB is the minimum fuel you must have at destination = alternate fuel + final reserve + extra. For LSGG with a typical close-in alternate (LFLB Chambéry), alternate fuel ≈ 1.5 t, final 1.1 t = 2.6 t. The FMS continuously compares predicted destination EFOB against this number; if EFOB drops below, you get a "DEST EFOB BELOW MIN" warning and need to consider diverting earlier.
What to take away
- FUEL PRED continuously predicts destination and alternate fuel against reserves.
- The routine is compare-against-plan at intervals, not read-the-number once.
- A drift has causes worth diagnosing: level, wind, configuration, anti-ice.
- Early detection converts a fuel problem into a fuel decision.
The rest of Performance & Fuel
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