uhb12b
The reason for that is that vortex is generated as a result of lift and that ceases at the moment the nose wheel touches the ground. Under normal circumstances this will occur well before the point at which the next departing aircraft will become airborne and therefore vortex separation is not applicable. It follows that a B737 can depart as soon as a preceding, landing B747 has vacated the runway. Whereas, if they were both departures or arrivals, 2 minutes would be required.
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