Ok,ok... There is a big problem. I am not at all an airline pilot, just 13 year old, and I really didn't check my profile, just clicked "yes" everywhere. My native language is french, but I am learning english. I AM NOT A PILOT!
Last question: So BLEED AIR is taken from high pressure stage or low pressure stage, depending on what we need...
But has the APU BLEED already got that air? Because at the beginning of the thread, the apu bleed air turned a box to turn the compressor, so does the APU BLEED AIR get's compressed twice, or does it come as normal air and then get's compressed?