How to read an aircraft range ring
Updated
A range ring marks every place within a set distance of an
airport. Type 3000nm@DXB in AvMap and it shades
everything within 3,000 nautical miles of Dubai. Bangkok (2,647
nm) and London (2,969 nm) fall inside. Singapore (3,157 nm) and
Johannesburg (3,463 nm) are just outside.
Why the ring isn’t round on a flat map
On the globe, a range ring is a true circle: every point on its edge is the same great-circle distance from the airport. A flat Mercator map stretches areas more toward the poles, so a large ring centered away from the equator looks like an egg that bulges toward the nearer pole. Very large rings can wrap across the 180° meridian or enclose a pole. Switch AvMap to the 3D globe to see the ring’s real shape.
Writing a range ring
A ring is a distance, a unit, @, and an airport code.
AvMap accepts nautical miles, statute miles, and kilometers, so
3000nm@DXB, 3452mi@DXB, and
5556km@DXB draw nearly the same ring. Rings can be mixed
with routes, separated by commas, as in
DXB-LHR, 3000nm@DXB.
Comparing aircraft or bases
Draw two rings from the same airport to compare two aircraft, or the same radius from two airports to compare bases. The table below compares 1,500 and 3,000 nautical mile rings from Dubai.
| Destination | Distance | 1,500 nm ring | 3,000 nm ring |
|---|---|---|---|
| Mumbai BOM | 1,040 nm | Inside | Inside |
| Cairo CAI | 1,305 nm | Inside | Inside |
| Istanbul IST | 1,636 nm | Outside | Inside |
| Nairobi NBO | 1,922 nm | Outside | Inside |
| Bangkok BKK | 2,647 nm | Outside | Inside |
| London LHR | 2,969 nm | Outside | Inside |
| Singapore SIN | 3,157 nm | Outside | Outside |
| Johannesburg JNB | 3,463 nm | Outside | Outside |
Great-circle distances from AvMap’s airport data.
Choosing a radius
Manufacturers publish a range for each aircraft model, usually in nautical miles and for a stated passenger load with standard reserves. That figure is a best case for those conditions. Many people draw a second, smaller ring next to it to show a more conservative figure.
What a ring does not tell you
- Winds. A ring assumes still air. Headwinds shorten the real reach and tailwinds extend it, so the reach changes with direction and season.
- Routing. Real routes are longer than the great circle. See why flight routes curve on a map.
- Payload and rules. Cargo, passengers, fuel reserves, and diversion rules for twin-engine aircraft all reduce what is practical.
Range rings in AvMap are for visualization and early discussion. They are not a substitute for performance data or flight planning.
Try it
Open 1,500 and 3,000 nm rings from Dubai, or see the 3,000 nm ring on the globe for its true shape.