How do I plan aircraft fuel and refuelling stops for a flight?

Plan aircraft fuel one leg at a time: calculate taxi, trip, contingency, alternate, final-reserve and any additional fuel using aircraft performance data and forecast conditions. Schedule a refuelling stop whenever that block fuel exceeds usable capacity or loading limits, or predicted landing fuel would breach the required reserve. Then verify airport suitability and fuel availability.

For Aviation & Real-World Flying, approved aircraft documentation, applicable operating rules and official weather and aerodrome information take precedence over simulator estimates. Published maximum range is not a fuel plan; it rarely represents your payload, routing, wind or required reserves.

What is the best time to choose fuelling stations in a flight plan?

Choose provisional refuelling airports while building the route, then make the final selection after the payload, forecast wind, weather and aircraft performance are known. Do this before filing or committing to the flight, not after the aircraft is already approaching its endurance limit.

Fuel availability, opening hours and operational conditions can change, so reconfirm them close to departure and again before leaving the preceding stop. An airport symbol showing fuel does not guarantee that the correct grade will be available when you arrive.

How does aircraft fuel planning work for each leg?

Each take-off-to-landing sector receives its own calculation, including the fuel needed after reaching the proposed stop. A common planning structure is:

required block fuel = taxi + trip + contingency + alternate + final reserve + additional or discretionary fuel

The categories and minimum quantities vary by jurisdiction, VFR or IFR status and type of operation. Our worked breakdown of taxi, trip, contingency, alternate and reserve fuel explains the calculation without treating one percentage as universal.

1. Establish usable capacity. Use usable fuel rather than total tank volume. Check the aircraft flight manual or pilot’s operating handbook for capacity, approved grades and tank limitations.
2. Apply loading limits. Determine how much fuel can be carried without exceeding ramp, take-off or landing mass, centre-of-gravity limits, runway performance or obstacle-clearance requirements.
3. Build the actual route. Include expected departure routing, climb, cruise, descent, approach and realistic diversions around terrain, airspace or weather. Straight-line distance is rarely the distance flown.
4. Convert distance into flight time. Apply forecast winds at the planned levels and use aircraft-specific climb, cruise and descent performance. A headwind increases time and fuel burn even though the map distance is unchanged.
5. Add the required margins. Contingency, alternate and final-reserve fuel serve different purposes. Review how those protected fuel categories differ rather than combining them into an unexplained buffer.
6. Compare required fuel with allowable fuel. If the block figure cannot be carried within tank, mass, balance and performance limits, shorten the leg or reduce payload where permitted.
7. Repeat the calculation. Treat every subsequent departure as a fresh leg with its own route, weather, alternate and uplift.

A fuel planning system is a calculation aid, not a substitute for sound input data. If its aircraft profile, wind, routing or reserve policy is wrong, the resulting fuel figure will also be wrong. Check what the system includes before adding reserves manually, or the same component may be counted twice.

When is a fuel stop required?

A fuel stop is required when the planned leg cannot be completed while preserving all applicable fuel requirements and operating limits.

• The required block fuel exceeds usable tank capacity.
• The fuel can fit in the tanks, but carrying it would breach mass, balance, runway or climb-performance limits.
• The expected landing fuel would be below the required alternate, final-reserve or other protected quantity.
• Uncertain winds, weather, routing or delays make the margin too small to support a credible diversion.
• Fuel availability farther along the route is doubtful, making an earlier confirmed stop the safer choice.

There is no universal maximum leg time or safe percentage of advertised range. A route may fit comfortably in still-air range and still be unsuitable with a strong headwind, heavy payload, lengthy approach or limited diversion options.

How do I choose a refuelling airport?

The best fuel stop is a suitable airport with confirmed fuel and useful operational margin, not the airport nearest the edge of theoretical range.

• Fuel specification: confirm the required grade, dispensing arrangement, nozzle compatibility, minimum uplift and any additive requirements that apply to the aircraft.
• Service availability: check opening hours, prior-arrangement requirements, payment restrictions and whether the fuel provider must be called out. Obtain direct confirmation when the stop depends on a single supplier or pump.
• Arrival suitability: assess runway dimensions, surface, wind, terrain, lighting, weather and available approaches.
• Departure performance: repeat the runway and obstacle calculation at the heavier post-refuelling weight, particularly in high temperature or at an elevated aerodrome.
• Legal and administrative access: account for permission, customs, immigration, security and operating-hour restrictions before committing to an international or restricted airport.
• Route efficiency: compare the detour and extra burn with the reliability, weather and runway advantages gained from the stop.
• Fallback: identify another suitable airport that remains reachable with the required fuel margin if weather deteriorates or the intended stop becomes unavailable before landing.

A pump failure discovered after landing may leave the aircraft safely stranded but unable to continue. That is preferable to departing with inadequate fuel, which is why service confirmation and a ground contingency matter on remote routes.

Should every refuelling stop be a separate flight plan leg?

Yes. A planned landing for fuel ends one operational leg and begins another; the refuelling airport should not be treated as an ordinary en-route waypoint.

Calculate and record each sector separately, and file another flight plan when required by the applicable rules and air traffic service. Our guide to planning a multi-leg route one sector at a time covers the handover between legs.

At the stop, replace estimates with actual information: establish the usable fuel remaining, obtain updated weather and operational information, account for payload changes and recalculate the next departure. Do not carry the original figures forward unchanged.

How much fuel should I add at the stop?

The planned uplift is the target block fuel for the next leg minus the verified usable fuel already onboard before refuelling.

planned uplift = target block fuel for next leg - usable fuel remaining

Keep every value in the same unit. The practical uplift calculation and unit checks explain how to handle fuel already onboard, expected ground burn and mass-to-volume conversion.

Do not automatically fill every tank. Extra fuel increases take-off mass, may reduce payload or climb performance, and consumes fuel simply by being carried. Tankering cheaper fuel only makes sense after those penalties and the next landing-mass limit have been considered.

After refuelling, compare the delivered amount with the requested uplift and expected total. Verify the units, indications and tank distribution, then complete the aircraft’s required checks for caps, vents, drains, contamination and tank selection.

How do I calculate total fuel cost?

Total fuel cost is the sum of the uplift purchased at each airport multiplied by that airport’s unit price, plus any fuel-related taxes, minimum-purchase charges or service fees.

total fuel cost = sum of (uplift quantity x local unit price) + fuel-related fees and taxes

Sum the planned uplifts, not every leg’s block-fuel figure. Fuel remaining after one leg is carried into the next and reduces the next purchase. If the plan uses kilograms or pounds but fuel is sold by litre, US gallon or imperial gallon, convert using an appropriate density for the delivered fuel and never treat those volume units as interchangeable.

What if wind, delays or remaining fuel differ from the plan?

Compare actual fuel remaining with planned fuel at meaningful checkpoints and revise the plan as soon as a shortfall or worsening forecast appears.

If the margin is shrinking, recalculate the reachable airports and divert to an earlier suitable fuel stop while the required reserve is still protected. Do not consume final-reserve fuel merely to make the original plan work. In real-world flying, follow the aircraft checklist, applicable fuel-emergency procedures and required communications.

What changes in a flight simulator?

The planning logic stays the same, but the simulator aircraft’s fuel burn may not match real-world handbook data. Default planners often use generic profiles, while detailed aircraft may calculate loading and fuel through their own electronic flight bag, flight-management system or aircraft menu.

• Use a performance profile that matches the simulated aircraft and its chosen power settings.
• Check whether the planner includes taxi, alternate and reserve fuel before adding them again.
• Load fuel through the aircraft developer’s intended method when one is provided.
• Confirm whether quantities are shown in kilograms, pounds, litres, US gallons or imperial gallons.
• Check tank distribution rather than looking only at the total quantity.
• Disable unlimited-fuel assistance when practising realistic fuel planning.

A mistake we see constantly is changing the simulator’s global fuel menu after a detailed aircraft has been loaded through its own system. The cockpit gauges, electronic flight bag and simulator state can then disagree. Recheck all three before departure, and use the aircraft-specific loading method where required.

Common fuel-planning failures and their fixes

• Using total instead of usable fuel: take capacity from the aircraft documentation and exclude unusable fuel.
• Planning from advertised range: calculate flight time with the planned payload, route, power setting and forecast wind.
• Spending the reserve in advance: keep final reserve and other protected quantities outside the planned trip burn.
• Choosing a stop at maximum endurance: move it earlier when diversion choices, weather or fuel availability are uncertain.
• Trusting a fuel symbol: verify the grade, hours and dispensing arrangements rather than relying on a directory entry.
• Filling the tanks without a loading check: recalculate ramp, take-off and landing mass, centre of gravity and runway performance.
• Mixing units: label every figure and convert mass and volume consistently.
• Reusing the original multi-leg figures: start the next calculation from verified fuel remaining and updated conditions.