Air packs for take-off VS 340-600

[22/04]

Having flown DEL/LHR and LHR/NRT/LHR in the last 3 weeks I notice that the airpacks were selcted off just before take off on Virgin A340-600s.

Is this a standard measure it does it depend on required performance.

[Hand Solo]

Pretty standard measure for most heavies unless they are fairly light. Saves on engine wear.