BA have a SOP that all takeoffs above 300 tons are packs off. It is not often a performance issue, more as has been alluded to, fuel and engine conservation. But they do operate hot and high where, on some days, packs off are required for performance.
eg. Jo'burg, Nairobi, Mexico.
And to muddy the waters, they also in addition load the aircraft with an aft C of G to squeeze the last kilo out of the performance.
Last edited by L337; 5th Feb 2009 at 04:52.
Reason: spelling