Pressurization Flashcards
What is the CPC?
Dual channel Cabin pressure controller
What is the OFV
Outflow Valve. Modulated by the CPC. Closes to increase pressure, opens to decrease pressure. In CPC failure, can be selected in Manual mode.
What is the NPRV?
Negative pressure relief valve
What is positive pressure relieve valve?
When differential pressure exceeds 8.6 PSI the valve opens. Connected to the static port.
Static port
Ensures proper operation of safety valve
CPCS automatic mode controls:
Cabin Altitude, Differential pressure, Cabin Altitude rate of change. Information taken from FMS.
What is the dump function?
Emergency evacuation, fast cabin depressurization, or smoke removal is necessary.
What happens when dump is pushed?
CPCS sets packs and recirc fans to off, controls outflow valve at a climb of 2000 ft/min up to 12,400 ft. Closes OFV at 12,400. Not available in manual mode.
Ground mode
WOW status on the ground, engines are running below takeoff thrust
Taxi mode
WOW status on the ground, doors are closed, engines are running at or above 60% N2.
takeoff mode
WOW status on the ground, engines are at takeoff thrust.
climb mode
CPCS calculates most comfortable rate of climb. depending on gross weight and ambient pressure. limited to +750 ft/min and -600 for decreasing.
Cruise mode
reaches FLT level entered in FMS. Below FL 370 7.8PSID and cabin alt will be 8,000. Above FL370 = 8.4 PSID.
Descent mode
Target cabin alt is LFE (landing field elevation) set in FMS. -200 to -750 ft/min.
abort mode
Activated when aircraft stops climbing and immediately begins descending without cruise mode. When pressure alt is less than 10,000ft or if the aircraft is less than 5000 ft above field elevation.
