Pressurization Flashcards
How high can the cj2 hold a sea level cabin altitude?
23,586 ft.
What cabin altitude would you have expect around FL450?
~8,000ft.
Give me a general description of how outflow air is controlled in a normal situation.
The pressurization controller send a signal to the climb or dive solenids at the primary ouflow valve.
The solenoids use 23psi service air for Dive and ejector vacuum for climb manipulating the control chamber of the outflow valves.
How do the cabin alt. safety limit valves work and when do they kick in?
They utilize cabin air to relieve vacuum pressre applied to the outflow valve control chamber at 14,500 ft +or- 500 ft.
What is happening with the outflow valves during a typical takeoff roll?
They are kept fully open initially by squat switches they close when throttles are advanced beyond 85% n2 and then enter flight mode when weight is removed from the wheels.
What are the inputs to the autoschedule?
Adc,departure and destination field elevation.
What is the difference between a red vs. yellow light on the pressurization controller?
Red indicates total failure while yellow indicates loss of adc input.
When would you get a cab alt master caution?
Cab alt of 10,000ft if 8,000 or less is set in controller or 14,500ft if 8,000ft or > is set.
What does the exer button do in the air?..on the ground?
In the air it does a light test on the ground it will close the outflow valves and drive the cabin down two hundred feet in about two minutes. Engines running and door must be closed.
When landing at ktex when would you expect a noticable difference in the way the cabin alt descends?
You would notice an increased rate of descent when passing through fl 245.
When would you expect a zero diff during arrival?
1500 ft agl.
When in isobaric mode are the climb and dive solenoids still in use?
Yes, the altitude controller is only capable of commanding the climb dive solenoids.
While at FL250 you hit the dump switch. Describe what should happen and how it is achieved.
The cabin should climb to 14,500 ft + or - 500ft. An electrical signal is sent to open the climp solenoid, then at 14,500 the altitude limit valve will then add cabin pressure to the vacuum air applied by the climb solenoid to regulate 14,500 + or - 500.
What protection is built into the outflow valves?
There are maximum cabin altitude and maximimum differential safety valves contained in each outflow valve.
