Air Conditioning & Pressurization Flashcards
How does ground air reach the system?
Connected thru the left air conditioning manifold and goes into the mix manifold then distributed.
Does ground air go thru the packs?
No
What is the function of the compartment temp control switches and how do they accomplish it?
Used to control temp in the associated zones. The knob adjusts the trim air valves for the associated zones to provide the desired temp.
When does the compartment temperature inop light come on?
- Duct temp over heat
- Fault in the temp control system
- Trim air selected off
- Associated temp control switch selected off
What does the C and W on the trim air valve control mean and what are the associated valve position?
C - cool, valve closed
W - warm, valve open
What are the min and max ranges on the automatic temp controller?
C - 65f
W - 85f
65 to 85 are the ranges
Do you have manual trim air control for fwd and aft cabin?
No.
Do you have manual control of trim air for cockpit? If so how do you accomplish that?
Yes. By selecting M on the controller and putting the switch to C or W will modulate the cockpit trim air valve
Is there a dedicated switch to close the cockpit trim air valve?
No unlike the fwd and aft cabin, there is no dedicated off position for the trim air valves. However you can still close it manually using the M mode on the controller
Which single valve is the trim air switch controlling?
The trim air regulating valve
Do we have recirc fans?
No
What is the function of the pack reset switch?
Reset the pack if it has cooled down
What does the pack inop light mean?
Pack overheat or a fault in the automatic control system.
Pack off light
Pack valve is closed
What temp will stby N set on the pack control knob?
75f
What temp will stby W set on the pack control knob?
STBY W sets the pack so the outlet temperature is controlled by ram air flowing across the pack heat exchangers. This pro-duces the warmest output possible without causing an internal overheat
Will the pack valve open or close when you set the knob to auto or manual?
The pack valve arms open.
How is the pack valve operated?
Electro Pneumatic.
Describe the PACK HIGH FLOW operation?
Ground operation whenever the APU or ground source is supplying air for air conditioning (both packs increase).
- Flight if one pack is off or inoperative.
The pack high flow system is inhibited when:
1. Wing anti-ice is on and only one engine is supplying bleed air.
- An engine is inoperative.
- Flaps are not in the up position.
- CARGO FIRE/DEPR switch is pushed
Describe PACK LOW FLOW ops?
- When the CARGO FIRE/DEPRESS switch is pushed, with both packs operating and in the same mode, the right pack is commanded OFF, and the left pack goes to low flow.
- For single pack operations, the operating pack goes to low flow.
What happens to the thrust limit of an engine in pack high flow ops?
When a pack is operating in high flow the displayed Maximum Thrust limit for the associated engine is automatically reduced.
What happens if the automatic pack control function fails?
The pack temp control valves freeze in the last position and the pack has to be run in the stby modes.
What is automatically done to the packs if the inop light comes on because of an overheat of the air leaving the packs?
The pack is automatically set and locked to maximum cooling if the INOP light illuminates because of an overheat in the air as it leaves the pack. After cooling, the pack can be reset for automatic or standby operation by pushing the PACK RESET Switch
What are some reason why a PACK OFF light may come on?
- Pack control selector off
- Pack trip has occured
- Pack has lost air supply
What happens to pack valve if you get a PACK OFF light?
Means pack valve is closed
What will the packs do if you turn the trim air off?
air conditioning packs default to a 75° F cabin temperature
What temp range will the fwd and aft cabin controllers be able to maintain with the main deck temp selector in the ANIMAL/NORMAL mode?
65f to 85f
What temp range will the fwd and aft cabin controllers be able to maintain with the main deck temp selector in the PERISHABLE mode?
35f to 71f
How many heaters do we have for the foot and shoulder heat for the pilots?
Each system has 2 heaters. One for foot and one for shoulder. The f/o and captain has independent systems.
Is the crew heat operable during ground ops?
No
How many pressurization controllers do we have?
2
What happens if one pressure controller fails?
The other one automatically takes control