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PNEUMATICS

If there is any conflicting information, your FCOM shall be the overriding reference.

Please read the footnote at the end of this page.

Q1. What are the uses of Pneumatic Air?

A1.  The pneumatic system supplies high-pressure air for :-

–>   Air conditioning

–>   Engine starting

–>  Wing anti-icing

–>   Water pressurization

–>  Hydraulic reservoir pressurization

Q2. What are the possible sources of HP Air?

A2.  HP Air has three possible sources :-

–>  Engine bleed systems

–>  APU load compressor

–>  HP ground connection.

Q3. What are the conditions in which Engine Bleed Valve close automatically?

A3.  The Bleed valve is fully closed :-

(a)  Pneumatically

–>  If Upstream Pressure goes below 8 Psi.

–>  If there is a return flow.

(b)  Electrically by means of :-

–>  The BLEED pushbutton switch (switched OFF)

–>  The ENG FIRE pushbutton (pushed)

–>  The Bleed air Monitoring Computer (BMC) in the following cases:

     (i)  Over-temperature

     (ii)  Over-Pressure

     (iii)  Leak

     (iv)  Open Starter Valve

     (v)  APU Bleed being ON.

Q4. During Climb or Cruise, is air bled from IP or HP stages of the Engine?

A4.  Air is normally bled from the intermediate pressure stage (IP) of engine’s high-pressure (HP)

compressor to minimize fuel penalty. At low engine speed, when the pressure and temperature of the IP air are too low, the system bleeds air from the HP stage and maintains it at 36 ± 4 PSI .

Q5. What is the normal Bleed pressure maintained by Engine Bleed Valve?

A5.  The Engine Bleed Valve maintains delivery pressure at 45 ± 5 PSI .

Q6. What happens to Engine Bleed Valves and to X bleed Valves {in Auto} when APU Bleed Valve is selected ON?

A6.  The Engine Bleed Valves are closed automatically.

Q7. What happens to No2 Engine Bleed Valve, when X Bleed Valve is shut and you select APU Bleed ON?

A7.  It remains open.

Q8. Which areas of the aircraft are monitored for bleed leaks?

A8.  Leak detection loops detect any overheating near the hot air ducts in the fuselage, pylons, and

wings.

Q9. What are the indications and effects of a left wing leak?

A9.  The following are the effects of a wing leak signal :-

–>  The bleed valve on the related side to close automatically

–>  The associated FAULT light on the AIR COND panel to come on

–>  The x-bleed valve to close automatically (except during an engine start)

–>  The APU bleed valve to close automatically (if it is open, and if the leak concerns the left wing)

(except during engine start)

The following are the indications of a wing leak :-

–>  FAULT Lt on the corresponding ENG BLEED P/b s/w on OVHD.

–>  The associated ECAM Warning to come on.

Q10. What are the indications and effects of a right wing leak?

A10.  The following are the effects of a wing leak signal :-

–>  The bleed valve on the related side to close automatically

–>  The associated FAULT light on the AIR COND panel to come on

–>  The x-bleed valve to close automatically (except during an engine start)

The following are the indications of a wing leak :-

–>  FAULT Lt on the corresponding ENG BLEED P/b s/w on OVHD.

–>  The associated ECAM Warning to come on.

Q11. With the BMC1 failure, what functions are lost?

A11.  The associated FAULT light on the AIR COND panel is lost, and the associated bleed

valve does not close automatically.

ENG BLEED LEAK warning is lost for the associated engine, as is also the APU BLEED LEAK

warning if BMC1 has failed.

Q12. With the BMC2 failure, what functions are lost?

A12.  .  The associated FAULT light on the AIR COND panel is lost, and the associated bleed

valve does not close automatically.

ENG BLEED LEAK warning is lost for the associated engine.

Q13. Is it True that leak detection is ignored during engine start?

A13.  No.

Q14. Is it permissible to use External HP Air for air-conditioning?

A14.  Yes.

Q15. Under which situations, do you get ENG 1 BLEED FAULT light?

A15.  The ENG1 BLEED FAULT Light comes on in the following conditions :-

–>  There is an overpressure downstream of the bleed valve.

–>  There is a bleed air overheat

–>  There is a wing or engine leak on the related side.

–>  The bleed valve is not closed during engine start.

–>  The bleed valve is not closed with APU bleed ON.

Q16. Under which situations, do you get APU BLEED FAULT light?

A16.  This amber light comes on, and an ECAM caution appears, when the system

detects an APU leak.

Q17. In cross bleed valve, if the position disagrees with selected position, what are the warnings?

A17.  The following are the warnings that will be generated in case of disagreement in position of X-Bleed Valve :-

–>  Single Chime Aural Warning

–>  Master Caution Light

–>  The BLEED SD page will show X-Bleed Valve position in Amber.

Q18. How will you be informed if X Bleed Valve fails to Open?

A18.  If the X Bleed Valve fails to open, the following would indicate its failure to open :-

–>  Single Chime Aural Warning

–>  Master Caution Light

–>  The BLEED SD page will show X-Bleed Valve position in Amber.

Q19. How will you be informed if X Bleed Valve fails to Close?

A19.  .  If the X Bleed Valve fails to close, the following would indicate its failure to close :-

–>  Single Chime Aural Warning

–>  Master Caution Light

–>  The BLEED SD page will show X-Bleed Valve position in Amber.

Q20. If an ECAM AIR ENG1 BLEED FAULT Caution is generated, is it necessary to switch OFF the associated Engine Bleed Switch?

A20.  The Engine Bleed automatically closes but in case it doesn’t close automatically, then the action should be to switch OFF the associated Engine Bleed switch.

Q21. Following an ENGINE 1 BLEED FAULT, why can you use only one pack if Wing Anti Ice (WAI) is on?

A21.  One Pack must be closed when the pilot is using wing anti-icing for pre-cooler performance.

Q22. In AIR DUAL BLEED FAULT Checklist/QRH procedure, why it is that in one case you have to descend to FL100 and in other case to FL 200?

A22.  The difference lies in the fact that in one case we can use APU Bleed Air to provide pneumatic supply to the pressurization system thereby preventing the cabin altitude from exceeding beyond limits. This is possible due to the fact that the APU Bleed source is left of the X-Bleed Valve position.

Q23. In flight, a dual bleed fault {AIR DUAL BLEED FAULT} occurs. The QRH procedure directs use of the APU for a bleed source. What is the maximum altitude for APU bleed operations?

A23.  FL200.

Q24. If there is a Wing leak or Engine Bleed leak, what important considerations apply to the rest of the flight?

A24.  With a Wing Leak or Engine Bleed Leak, one should take precautions to avoid Icing Conditions.

Q25. To which side of the X bleed valve, is the Ground HP connection?

A25.  Left.

Q26. What are the positions of the X Bleed Selector?

A26.  The following are the positions of the X-Bleed Selector :-

(i)  AUTO

(i)  OPEN

(iii)  SHUT

Q27. Does BLEED page show positions for HP BLEED Valve, Engine BLEED Valve and Wing Anti Ice Valve?

A27.  Yes.

Q28. When does engine identification number on ECAM Bleed page turns amber?

A28.  It becomes amber, when engine N2 is below idle.

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2 thoughts on “PNEUMATICS”

  1. thanks for your help to make the subject clear .may I ask you a quesion pls. In case on ECAM .Eng. Bleed Valve not close .and you had done the deactivation procedure for the eng. bleed valve but the message remain and the valve shown in the bleed page in amber and open . you found that the cannon plug was damaged . how you can dispatch the A/C. can you consider it as wrong indication and dispatch the aircraft and record it in TLB as C/F . or you should replace the cannon plug for dispatch (A320 ENG V2500)

  2. Correction for question number 13

    Note: 1. Leak detection is disregarded during an engine start.
    copied from FCOM

    thanks for help 🙂

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