Flashcards in Bleed Air : Pneumatic Deck (18)
How does the bleed pressure regulation work?
The bleed valve, which is downstream of the junction of HP (high pressure) and IP (intermediate pressure) ducting acts as a shut-off and pressure regulating valve. It maintains delivery pressure at 45 +/- 5 psi.
How does the bleed temperature regulation work?
A precooler downstream of the bleed valve regulates the temperature of the bleed air. The precooler is an air-to-air heat exchanger that uses cooling air bleed from the engine fan to regulate the temperature to approximately 200°C.
Which systems or components are supplied by high pressure air?
Air conditioning, engine starting, wing anti-ice, water pressurization and hydraulic reservoir pressurization.
What are the high pressure air sources?
Engine bleed systems, APU bleed, and HP ground connection.
Pneumatic system operation is controlled and monitored by...
Two Bleed Monitoring Computers (BMC).
What occurs if one Bleed Monitoring Computer (BMC) fails?
If one BMC fails the other one takes over most of the monitoring functions.
On which ECAM page will you get information about the PNEUMATIC system?
How does the APU bleed valve controlled and operated?
Electrically controlled and pneumatically operated.
How does the bleed leak detection work?
Leak detection loops detect any overheating near the hot air ducts in the fuselage pylons and wings. For the pylon and APU the sensing elements are tied to form a single loop and for the wing a double loop.
What is the function of the crossbleed valve?
The crossbleed valve on the crossbleed duct allows the air supply systems of two engines to be isolated or interconnected.
Which logic controls the X-Bleed valve when the X-BLEED switch is in auto?
- When APU bleed valve is open, the x-bleed valve is open
- When APU bleed valve is closed, the x-bleed valve is closed
- X-bleed also closes for wing, pylon, or APU duct leak (Except during engine start)
What does the amber "FAULT" light in the APU BLEED pushbutton indicate?
Bleed leak (APU Bleed valve closes)
On the ECAM Bleed page, how do you tell if the GND HP air supply is connected?
ECAM BLEED sd page, the left precooler will read a temperature and pressure. NOTE - the green GND and triangle are always displayed on the ground, regardless of connection.
If the APU is running, is it necessary to manually select APU BLEED OFF prior to APU shutdown?
No. When the APU MASTER sw is selected OFF, the bleed air valve is closed and the APU is allowed to cool prior to shutdown
How can you tell if the GND LP air supply is removed before selecting the APU BLEED pushbutton to on?
Turn off the CAB FANS pushbutton, open the air vent on the instrument panel and confirm no airflow.
What flow rate is automatically selected when APU bleed air is in use or during single pack operation?
If the engine bleed air in-flight is too low, what will occur?
Engine speed is automatically increased to provide adequate bleed air pressure