Air Conditioning Flashcards
Provides?
Air renewal, constant selected temp
Zones
Cockpit, fwd cabin, aft cabin
Supplied by pneumatic system via?
Two pack control valves
Two packs
Mixing unit (cabin and packs)
Ram air?
Ambient air to mixer in emergency
Temperature regulation by?
Zone controller and two pack controllers or two ACSC (AC system controller)
Temperature regulation
Hot air regulating valve, and trim air valves, tapped upstream of packs, mixed after mixer
FAP control (flight attendant panel)
+- 2.5 degrees
AC Controller 1, 2
1 controls cockpit
2 controls fwd cabin, aft cabin
Pack flow control valve
Pneumatically operated, electric control, spring loaded to close
Closes when: pack overheat, engine start, operation of fire switch
Emergency ram air
Ventilates in case of: smoke, fail of both packs
Won’t open if DP more than 1 psi
Hot air valve
Pneumatic operated, electrical control, spring closed
Closes if: Both ACSC fail, duct overheat, two trim air valves fail
Fails if duct temp reaches 88 degrees
Trim air valve
Electrically controlled
Cockpit, ACSC 1
Cabins, ACSC 2
Temp regulation
Temp selectors in cockpit, zone controller computes a temp demand, then fine tuned on the FAP
Range 18 - 30
Pack flow control
High flow auto for:
Single pack op, APU supply
Normal auto:
LO selected and temp demand not satisfied
Lane fail
One pack fails, the other takes over
Both, hot air valve closes, trim valves remain in current position
