A320 V speeds

[Boyington]

Why is it that in the Octupus speed charts of the A320, the V Speeds for a lower Takeoff weight is higher than that for a higher takeoff weight, all other conditions and limitation codes being the same.

[MD80rookie]

Could you attach the chart for reference?

[tubby linton]

To improve performance the speeds are adjusted/optimised to give a higher V2 . at higher weights you are seeing the "real" speeds.
http://www.pprune.org/tech-log/41321...d-v-speed.html

[Boyington]

V Speeds in A320

In the Octopus charts for some fields on the A320 the V speeds for a lower weight are higher than that for a higher Take off weight, all other conditions like limitation codes etc remaining the same. Why is it so?

[Cough]

Briefly - Increased V2 climb.

Having a higher V2 can lead to greater flex temps. When you are light you can accelerate to the higher speeds in the runway length hence use a greater flex.

When heavier, you can't accelerate as quickly, so the flex temp falls rapidly as engine thrust compensates for aerodynamic inefficiency.

[vilas]

Boyington
In this case you are obstacle and brake energy limited.

• To reduce take off distance you should increase V1 but V1 is limited by MAX brake energy speed.
• The brake energy limitation depends on weight and thrust.
• When OAT increases the weight and the thrust decrease.
• When OAT increases, MAX V1 limited by MAX brake energy speed increases.