Environmental System Controls

     As you can see, two switches, two knobs, and a cherry picker does it all for pressurization, unless the cabin altitude excceeds 9500 ft.  Above that, the emergency bleed valves open, bypassing the flow control valve, and pumping raw bleed air into the cabin.

     Temperature control is pretty simple.  The crew and the cabin have their own temperature control in both auto and manual.  The freon system has a three position switch, and the Aux heat has Lo Hi and Off.  Aux heat works on the ground with a generator or GPU on line.  Freon is limited to 18,000 ft and is not supposed to be used during takeoff and landing.

GO Back to Lear 55 Study Guide