Pit Groben

Okay, but then you should also not be able to start the engines with the same ground air otherwhise that would be a little contradictory.

Thanks for your reply. But if the air from the ground cart is going into the manifold then why are there 45 PSI in the bleed air system as indicated in the EICAS ECS Page? AFAIK the CRJ-700 can receive low-pressure air from a ground car to the manifold as well as high pressure to the bleed air system. With the ground cart simulated it is possible to start the engines so that would indicate as well that the simulated ground cart delivers high pressure air?

The packs are outlined in white on the ECS page with ground air prior to APU start and the sensed temperature is equal to the outside temperature. When the APU has been started and then shut off, the packs are outlined in green and the sensed temperature is increasing to the selected temperature.

When the aircraft is on ext AC power and ground air is connected, the aircraft packs wont start. The fault lights disappear though. When the APU is started once and then shut off the aircraft packs work as intended with the ground air cart.