Range calculator
Range is endurance turned into distance by groundspeed. Because groundspeed carries the wind, the same fuel gives very different ranges on different days.
Calculator
This is an educational and planning aid. Use current official weather, your aircraft flight manual, and the rules that apply to your flight before you act on any figure here. See the aviation disclaimer.
What the result means
The main figure is how far you can fly with the endurance you have, at the groundspeed you expect to hold.
The radius of action shown underneath is half that, and it only means anything if the groundspeed is the same in both directions. With a real wind it rarely is, which is what the point of no return calculator exists for.
When this is useful
- Checking whether a destination is reachable on the fuel available before planning the route in detail.
- Comparing how far the same fuel takes you with and against a forecast wind.
- Sizing up whether a fuel stop is needed on a long trip.
How it is calculated
Multiply the endurance by the groundspeed. Endurance should already have the reserve removed, and groundspeed should already include the wind.
range = usable endurance x groundspeed
Worked example
- Usable endurance
- 3 hours 30 minutes
- Planned groundspeed
- 110 kt
Range is 385 NM, giving a radius of action of about 192 NM in still air.
Check: 3.5 hours at 110 kt is 385 NM. As a cross check, in 1 hour you cover 110 NM, in 3 hours 330 NM, and the remaining half hour adds 55 NM, totalling 385 NM.
Limitations
- It assumes one groundspeed for the whole flight. Climb and descent are flown at different speeds, and the wind changes with altitude and along the route.
- A headwind hurts range twice over. It lowers your groundspeed, and it means the engine runs longer for every mile covered.
- This is not the aircraft maximum range. That depends on flying at the best range speed and power setting from the flight manual, which is usually slower than a normal cruise.
Common mistakes
- Entering true airspeed instead of groundspeed, which quietly removes the wind from a calculation that exists to show the effect of wind.
- Using endurance that still includes the reserve.
- Treating the radius of action as usable when there is a significant wind, since the return leg will have a different groundspeed.
Sources
- Pilot's Handbook of Aeronautical Knowledge, aircraft performance , US Federal Aviation Administration