Walkthrough / Guide including AOC/ATSU flows for A319-A321 **UPDATED 7th Jan 2020**

[Koen Meier 1456]

3 minutes ago, Alaa Riad said:

Hi Koen, I meant how do I know "as a pilot" when to turn them off or leave them on? is there a chart or indication for that?

There is no chart or indication for it. I usually run 1 pack on the ground and turn that one off when reaching the holding point if i was doing a pack less takeoff. This keeps passenger comfort at a good level. If i was doing a a take off with packs i leave both on when on the ground.

certainly in summer in hot destinations and short runway. Having both packs on at high till i reach the holding point as it helps comfort.

for places like Innsbruck i keep the packs on but i use the apu bleed to drive the packs instead. This will cause the engines to still have the same power.

[David Murden 930]

To add to what Koen says.

Its also airline SOP, e.g BA like packs OFF for take off, another airline like USA ones like packs ON. There is no right/wrong. Its down to weather temp etc and Airline SOP.