747 Speeds
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747 Speeds
As long as the runway could give adequate V1 how would you 747 pilots feel about an increase in Vr by 10 kts, thus an increase in V2 by 10 kts? I understand that V2 must be accomplished such that if the critical engine fails you must be able to make obstacle clearance.
If operational procedures were to change such that a "variable" Vr was used to enhance climb how would you pilots feel? In this I mean: Leave V1 the same as you have it today. Your initial Vr would still be the same as today. But if nothing has gone wrong(ie. engine failure) you stay on the runway till you reach your optimal Vr. If something does happen you can climb at any point between the two Vr points. Lets call them Vr "initial" and Vr "optimal". All of the safety margins are still the same. If an engine fails between Vr initial and Vr optimal the plane's increased velocity will only help engine out climb and remember you can rotate anytime between the two Vr points in case of an emergency. Vr optimal would have to be such that if critical engine fails at Vr the plane can still make obstacle clearance.
This second scenario will give you more altitude at cutback due to increased climb rate. Some of you already initiate cutback below 1000'. This will put you above 1000' ft at most airports that can handle a 747.
If operational procedures were to change such that a "variable" Vr was used to enhance climb how would you pilots feel? In this I mean: Leave V1 the same as you have it today. Your initial Vr would still be the same as today. But if nothing has gone wrong(ie. engine failure) you stay on the runway till you reach your optimal Vr. If something does happen you can climb at any point between the two Vr points. Lets call them Vr "initial" and Vr "optimal". All of the safety margins are still the same. If an engine fails between Vr initial and Vr optimal the plane's increased velocity will only help engine out climb and remember you can rotate anytime between the two Vr points in case of an emergency. Vr optimal would have to be such that if critical engine fails at Vr the plane can still make obstacle clearance.
This second scenario will give you more altitude at cutback due to increased climb rate. Some of you already initiate cutback below 1000'. This will put you above 1000' ft at most airports that can handle a 747.
