Air Management System Flashcards
What are the 4 things that the engine/APU bleed air can provide for?
Anti Ice (Engine bleed air Only)
Water Pressurization
PACKS/ECS (APU can up to 15,000ft)
Engine Start
Where does the bleed air come from?
Engines and APU
Takeoff ECS ON or ECS OFF differences
ECS ON = Engine providing bleed air for ECS
ECS ECS OFF = APU providing bleed air for ECS
Purpose and function of the Air Recirculation Fans? When will AUTO shut down?
Recycles the cabin air and will turn on automatically when one PACK comes on
Will automatically turn off if both PACKs are off and when smoke is detected in the cargo or recirculation bay
Total flow and consistency of recirculation fans?
52% fresh air and 48% recycled
Components of pressurization system
• 2 CPCs - Cabin Pressure Controllers. Regulators that control the cabin pressure.
• OFV - Outflow Valve. Modulates airflow and controls pressurization
• NPRV - Negative Pressure Relief Valve. Automatically opens and keeps the max differential pressure above -0.5psi
• Safety Valve - Positive Pressure Relief Valve. Automatically opens if cabin differential pressure exceeds 8.6 PSI. Keeps the max differential pressure below 8.8psi Spring loaded/mechanical (requires no power)
• Static Port - a heated port that sends information to the Safety Valve to keep plane within
OFV
Outflow Valve. Modulates airflow and controls pressurization
NPRV
Negative Pressure Relief Valve. Automatically opens and keeps the max differential pressure above-0.5psi
Safety Valve
Positive Pressure Relief Valve. Automatically opens if cabin differential pressure exceeds 8.6 PSI. Keeps the max differential pressure below 8.8psi Spring loaded/mechanical (requires no power)
Static Port-
a heated port that sends information to the Safety Valve to keep plane within tolerances
Where is the Ram Air Valve and what is the purpose?
Underneath on the belly of the aircraft Provides emergency ventilation in case of PACK shutdown or smoke removal The Ram Air Valves are automatically commanded OPEN if both PACKs are OFF below 25,000ft Includes a check valve that only allows ram air into the cabin when ram air pressure > cabin air pressure
What is a PACK?
Pneumatic Air Conditioning Kit that provides cabin heating, A/C, and pressurization from the same side engine. There is a Xfeed for the PACKs bleed air if engine or pack fails however aircraft is limited to FL310
When will the PACK come on and off in AUTO?
Will come on when engine or APU bleed air is available
Will turn off during engine start or an associated bleed duct leak is suspected (amber light on button)
When will the XBleed come on and off in AUTO?
Will come on when bleed air is available on one side but not the other
Will turn off bleed leak is detected (unless starting an engine) or when the engine fire extinguisher handle is pulled
What are the external air connections?
High Pressure for engine starting (Huffer Cart) and is used when APU is INOP. IS shown on ECS synoptic page Low Pressure for cabin heating and cooling (used at most airports). IS NOT shown in cockpit
When will Engine Bleed come on and off in AUTO?
Will come on when respective engine bleed is available
Will turn off if fire is detected in respective engine or there is a bleed duct leak or overpressure detected
When will APU Bleed come on and off in AUTO?
Will come on when APU bleed is available
Will turn off:
if bleed duct leak is detected
A/I comes on or
left engine bleed is available
What does MAN do in the pressurization panel mode selector
Manual control of OFV. Moving Down closes the outflow valve pumping more air in. Moving Up opens outflow valve letting air flow out
What does AUTO do in the pressurization panel mode selector
Generates a pressurization schedule based on the departure, cruise, and destination heights set in the FMS
What does LFE CTRL do in the pressurization panel mode selector. How do you know it is on?Is pressurization still AUTO?
If destination elevation is not in the FMS database we can manually set it; however the pressurization will still be automatic. Manual elevation will have a cyan M on the EICAS
When would you use the CABIN ALT knob?
When the QRH says to manually take over the pressurization.
Does the function of the CABIN ALT knob rely on a position of the MODE knob?
Yes, you need to be in Manual mode.
Does the function of the LFE knob rely on the position of the MODE knob?
Yes, you need to be in LFE mode
Where does the LFE altitude read out in the aircraft?
On the EICAS screen Cyan M
