Hi Speedwinner,
If you've done the performance calculation assuming packs off and suffer an engine failure, the you shouldn't turn on the 1st pack until after the first thrust reduction (MCT).
Just one pack selected on the operative engine side keeps ECAM happy. If you open the cross bleed, then ECAM will invite you to turn on the second pack.
Last edited by rudderrudderrat; 5th Oct 2013 at 09:36.
Reason: Extra line