Formula
The distance is the great-circle length on a sphere with a mean radius of 6,371 kilometers:
hours = nautical miles / knots + taxi minutes / 60
A nautical mile is 1.852 kilometers. The trip time page divides a distance you already know by a speed and does not use coordinates.
Assumptions
- The Earth is treated as a sphere of 6,371 kilometers.
- The aircraft flies the great circle at a constant speed.
- Taxi minutes cover both ends together. Wind and airways are ignored.
Worked example
From 40.64°N, 73.78°W to 51.47°N, 0.45°W at 480 knots, plus 30 minutes of taxi, takes 6 h 44 min.
Input definitions
- Great circle
- The shortest path on the sphere between the two coordinates.
- Block time
- Airborne time plus the taxi minutes you type.
Limitations
This is a great-circle sketch, not a flight plan. It ignores wind, airways, and holding.
Questions
Which radius is used?
6,371 kilometers, a mean Earth radius, converted to nautical miles by dividing by 1.852.
Can I enter a known distance instead?
Yes, on the trip time page. This page is for when you have coordinates rather than a route distance.