A320 Pack Flow Question

[Club World]

Hi

Just wonder if somebody would kindly explain the following:-

On the A320/330

1)When Pack is selected to off for t/off, are both packs swithed off?

2)Why do some display on the upper ECAM say "Pack Flow High", what does it mean?

Thanks

[longarm]

1) For packs off take offs both are turned off. Some companies use packs off take offs everywhere to reduce engine wear.
2) The packs have selectable flow rates. With a light passenger load you can selects low, this reduces fuel consumption (you'd be hard pushed to notice though). We select low with pax figure of 120 or less (180seats). When packs are operated by the APU the flow rate is always high.

[Club World]

Thanks for reply, really helpful thanks.

Just with regards to Pack Flow High Inflight, does that mean that the APU is running during the cruise phase?

Thanks again

[smudgethecat]

During the cruise under normal conditions all bleed air requirements are supplied by the engines ,the apu is generally only used to supply bleed air on the ground with engines shutdown ,in fact with the engine bleed switches in the on postion the engine bleed PRSOV,s will not open until the apu bleed is selected to off if i remember rightly.