Air Management System Flashcards
The AMS is a pneumatic system that provides power ECS (Environmental Control System)
to the following:
- Engine and wing anti-ice
- Water pressurization
- Engine starter
Where can you find ECS info on MFD?
Environmental Control System (ECS)synoptic page on the MFD.
What are the sources for the ECS?
There are three potential bleed air sources to power the ECS:
Engine 1
Engine 2
APU
How to set cockpit and cabin temperatures?
set using the control knobs on the overhead panel.
*If Pax Cabin Knob is set to ATTND, FA’s have control of cabin temperature.
Outflow Valve (OFV) Purpose
Controls airflow from the cabin to the outside ambient air. This controls pressurization. About the size of a small pizza.
Ram Air valves Purpose
Provides emergency ventilation in case of:
- PACK shutdown
- Smoke removal
The ram air valves are automatically commanded OPEN if both packs are off below 25,000’
What are PACK’s?
Pneumatic Air Conditioning Kit. Two PACK’s provide:
- Cabin heating, air conditioning, and pressurization. Each PACK is normally supplied bleed air by the same side engine. A single engine bleed can supply both PACKs when the crossbleed valve is open
Limitation of a PACK:
A single PACK is capable of keeping adequate cabin/cargo hold pressurization and temperature up to 31,000’
What is the Safety Valve?
(Positive Pressure Relief Valve)
- Protects the airplane’s structure from damage due to the positive overpressure
- Automatically open if the cabin differential exceeds 8.6 PSI
- Spring loaded/mechanical (requires no Power)
When does the negative pressure relief valve open?
Automatically opens if the cabin exceeds -0.5 PSI
Not displayed on the MFD
APU can supply bleed air for:
ECS - up to 15,000’
Water Pressurization
Engine Start - Up to 21,000’
For which cargo bay does the ECS provide ventilation for?
In for Forward cargo bay only for live animals and dry ice.
Temperature Control knobs require which PACK for function?
PACK 1
Recirculation Fans Button:
Off - ( pushed out, white striped bar illuminated)
Auto - Turns On recirc fans when:
- At least one pack is on
Turns recirc fans off when:
- Both packs are off
- Cargo or reciculation bay SMOKE is detected
Which pack does Passenger Cabin Temperature Control knob require for operation?
PACK 2
Operations of PACK 1 or PACK 2 Buttons:
Auto - Opens the pack flow valve (turns PACK on) when:
- Bleed air is available
Closes the valve (turns PACK off) automatically:
- During engine start
- associated bleed system duct leak is detected
Operations of XBLEED buttons:
Auto - Opens XBLEED valve when:
- Bleed air source available on one side but not on the other side
Close the valve automatically when:
- Bleed leak detected (unless starting engine)
- A fire extinguishing handle has been pulled
There are two external air connections. What are they and what are they used for?
HP(High Pressure) - for engine starting
- Used if APU is inoperative
- Shown on ECS synoptic page (HP only)
LP(Low Pressure) - for cabin heating and cooling
- Used at most airports
Operation of Engine Bleed 1 or 2 buttons?
Auto - Opens the engine bleed valve when:
- The respective engine bleed is available
Closes the valve automatically when:
- Fire is detected in the respective engine
- Bleed duct leak or overpressure is detected
Does the APU supply bleed air to the anti-ice system?
APU cannot supply bleed air to the anti-ice system. It doesn’t produce bleed air at the volume or temperature required for anti-ice
Operation of APU Bleed button?
Auto - Opens the APU bleed valve automaitcally when:
- APU bleed is available
Close the valve automatically when:
- APU or left bleed duct leak is detected
- Anti-ice sytem is ON
- Left engine bleed is avaialble
In regards to pressurization, when can the CABIN ALT knob be used?
It can be used when the MODE knob is set to manual.
What does the CABIN ALT knob control?
It controls the position of the OFV(Outflow Valve).
What do the three positions of the OFV do?
Down: OFV is moved toward the closed postion (increases pressure inside the cabin)
Stop: OFV movement stops. Springloaded to this postion
Up: OFV is moved toward the open postion (decreases pressure inside the cabin)
What does the caged DUMP button do?
Momentary pushbutton
Provides rapid cabin depressurization by:
- Opening the OFV to command a 2,000 FPM climb to 12,400’ cabin altitude. At 12,400 ft cabin altitude, the OFV closes
- Commanding PACKs off
- Commanding recirculation fans off
Operation of the MASKS DEPLOY knob:
OFF: Disables automatic deployment
Auto: Automatically deploys the passenger O2 masks when the cabin altitude reaches 14,000 to 14,750 ft.
OVRD: Deploys the passenger 02 masks
How many minutes of O2 is supplied to passenger oxygen masks?
The masks are supplied oxygen by an oxygen generator. Supplies about 12 mins of O2.
What is the max differential pressure between cabin and ambient air?
- 8 PSI: 37,000’ and below
8. 4 PSI: Above 37,000’
