CRJ-700 Pro 5 Systems Practice Test

Bleed air source for the packs is chosen on the bleed air panel. That panel lets you select which source feeds the environmental control system packs: Engine 1, Engine 2, or the APU. This control directly determines where the conditioned air for the packs comes from, which is important for cabin conditioning and pressurization, especially on the ground with the engines off or when prioritizing a particular source. The automatic crossfeed valve control is related to balancing or supplying bleed air between sources if needed, but it is not the control that selects the packs’ bleed source. The fuel panel and the electrical load management computer do not control bleed air.