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Old 14th March 2011 | 06:12
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Wizofoz
 
Joined: Jun 2001
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From: Boldly going where no split infinitive has gone before..
On the 777, the FMC provides the Vx, which is usually around 240-270 kts. Vy is Vref30+ 140 (which is also Vcl + 60).

We use them in the standard way- to meet a lateral requirement (cross X at or above Y) we use Vx, to meet a time requirement (expedite trough X leve) we use Vy.

V2 IS the best speed to fly for obstacle clearence after takeoff, as the acceleration segment to get to Vx would rob to much distance, which I think is what Genghis was alluding to.
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