Bleed Air System Flashcards
What is the bleed air used for
Bleed-air is used for air conditioning andpressurization, anti-icing, and engine start-ing, as well as for pressurizing the hydraulicand water tanks
Where does bleed air come from on the ground and in the air
Bleed-air is supplied by the engines. On the ground bleed-air can besupplied by the APU, or the high-pressureground connection. The bleed-air system iscontrolled from the AIR CONDITIONINGpanel. Failures will be detected and the rele-vant alerts are presented. In case of enginefire the respective bleed-air system is shut offwhen the fire handle is pulled
Where is pneumatic pressure indicated and what does it show
Overhead panel and it shows the bleed air pressure
When is HP air normally used
During idling, the HP bleed valveopens fully to supply pressure
What valve normally regulates duct pressure
When enginepressures become excessive the PressureRegulating and Shut-Off valve (PR/SO) willlimit the downstream pressure.
What protection is there against duct overpressure in case this valve fails
When enginepressures become excessive the PressureRegulating and Shut-Off valve (PR/SO) willlimit the downstream pressure. If a failure ofthe PR/SO valve causes excessive ductpressure, the Over Pressure and Shut Offvalve (OP/SO) will limit the downstream ductpressure, and an alert will be presented
How and when is bleed air temperature controlled
Switching any anti-icing system ON will acti-vate the temperature modulating function ofthe HP bleed valve to admit such HP bleed-air to the LP bleed flow that the required tem-perature is maintained
What happens to the system at high engine thrust or when TOGA is activated
The modulating func-tion is inhibited for 60 seconds when TOGAis activated, or continuously while eitherthrust lever is selected to maximum take-offposition.
What valve will close if a duct overheat situation occurs
Overheat switches, when activated, will auto-matically close the respective HP bleed andPR/SO valves, and an alert will be pre-sented. The OP/SO valve remains open toprovide bleed-air from the other engine forengine anti-icing.
What valve will close in case of duct leak
If detected, the respective HP bleed,PR/SO, and OP/SO valves will close and analert will be presented
What happens to the system if a fire handle is pulled
The OP/SO valve will close
What level alert is a double bleed fault
Level 2
What causes an APU BLEED message to be displayed
If thevalve position is not correct, an alert will bepresented.only on ground
When would APU BLEED VALVE show
Reverse flow through theAPU due to a failure of the check valve willbe detected, the respective HP bleed, PR/SO, and OP/SO valves will close and an alertwill be presented, only in the air
What is the result of reverse flow through the APU check valve
When engine bleed-air is avail-able a check valve will prevent reverse flowthrough the APU. Reverse flow through theAPU due to a failure of the check valve willbe detected, the respective HP bleed, PR/SO, and OP/SO valves will close and an alertwill be presented
