Equal Time Point (ETP) Calculator
Find the point where continuing and returning take the same time. Enter the distance between the two airports, your diversion speed and the wind along the route.
Formula
ETP distance from A = D × H ÷ (O + H), where D is the distance between the airports, O is the ground speed when continuing to B (speed + tailwind) and H is the ground speed when returning to A (speed − tailwind). The time to either airport from the ETP is then equal.
FAQ
Why is the ETP not at the midpoint?
Wind along the route makes one direction slower than the other, so the point where the times are equal moves toward the airport that is harder to reach.
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