Study Guide-Air Condition Panel Flashcards
What computers monitor and control the pneumatic system?
2 BMCs (Bleed Monitoring Computer)
If one BMC fails, can the other take over?
Yes
The PACK FLOW selector has a LO, NORM, and HI positions. What is the rule of thumb for the setting?
If the total cabin occupancy (FAs+Pax) is 138 people or less, place the PACK FLOW selector to the LO position.
What would cause an amber PACK FAULT light to illuminate?
-Pack Overheat or a switch position disagreement with the FCV (Flow Control Valve).
What does an amber FAULT light in the APU BLEED pb indicate?
Bleed leak
What causes the amber FAULT light on the ENG BLEED pb indicate?
(3)
-Engine bleed temperature or pressure limit exceeded.
-Switch/Valve position disagreement.
-Bleed leak detected
What happens when the Ram Air pb is pressed?
This pb is used to open the emergency ram air inlet. In the normal position (lights out), the emergency ram air inlet is closed. When the guard is lifted, an the pb depressed, “ON” illuminates blue, and the ram air inlet opens.
“RAM AIR ON” is displayed in green on the memo display. Once the cabin differential pressure is less than 1 psi, the outflow valve will automatically open (if the cabin MODE SEL pb is in AUTO). The emergency ram air inlet and the outflow valve will not open if ditching has been selected.
What logic controls the X-Bleed valve when the X-BLEED switch is in AUTO?
-When the APU bleed valve is OPEN, the X-Bleed valve is open.
-When the APU bleed valve is CLOSED, the X-Bleed valve is closed.
What is the function of the HOT AIR pb?
The hot air valve controls the supply of hot air to all of the trim air valves, which maintain the selected temperature in each zone.
-Valve position is controlled by the HOT AIR pb. The valve automatically closes in the event of a fault.
What does the amber HOT AIR FAULT light indicate?
Duct overheat. The Hot Air valve closes automatically.
How does the system optimize the temperature in each of the 3 zones?
-Trim Air Valves
-To maintain the selected zone temperature, the trim air valves under the control of the zone regulator, add hot air, if necessary, to the air flowing from the mixing unit.
-This allows for air temperatures to be controlled independently in each zone.
What effect will the engine start sequence have on the pack flow control valves?
The pack flow control valve will close automatically.
After engine start with the APU BLEED pb ON, what source is supplying bleed air to the packs?
APU Bleed.
