Boeing 737 NG Systems Review
Forward Overhead Panel  800/900
Display Selector
Bleed Air Panel 800/900
Air Conditioning PACK Switch

OFF –
  • Pack is signalled OFF.

AUTO –
  • With both packs operating, each pack regulates to low flow.

  • With one pack operating, the operating pack regulates to
    high flow in flight with the flaps up.

  • When operating one pack from the APU (both engine
    BLEED air switches OFF), regulates to high flow.

HIGH –
  • Pack regulates to high flow.

  • Provides maximum flow rate on the ground with the APU
    BLEED air switch ON.