A320 pneumatic system
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A320 pneumatic system
Fellow pilots, pardon me if my question sounds stupid. I am new and really confused about the A320 bleed system. Suppose we have a single engine failure at low level, during ECAM actions, my company recommendation is to turn on the APU for additional electrical support, however, it is not common practice for us to use the APU for bleed support for the packs.
Correct me if i am wrong but according to the best of my knowledge, wouldn't using APU bleed as additional support will give your engines a slight boost in performance because packs rob bleed air and slightly decreases your engine performance, isn't it? if this is true, then why not use APU bleed incase of one engine out?.
Ive asked many senior ranking officers and captains around me but most of them do not give me a straight answer and keep beating around the bush. However, one senior officer did told me that, we can use it, depending on which engine has failed, and wether it is damaged or not, because if we turn on cross bleed, the damaged engine might cause foreign objects to enter the bleed system. Is this true? But if the engine is already damaged, wouldn't we have pushed the engine fire pushbutton and shut off the corresponding engine bleed valve? how is it possible then to get contamination? where can i find more info about this issue? because ive seen searching through the FCOMS and CBT but cant seem to find the answer to this
. Your comments and answers are aprreciated, thank you all in advance.
Correct me if i am wrong but according to the best of my knowledge, wouldn't using APU bleed as additional support will give your engines a slight boost in performance because packs rob bleed air and slightly decreases your engine performance, isn't it? if this is true, then why not use APU bleed incase of one engine out?.
Ive asked many senior ranking officers and captains around me but most of them do not give me a straight answer and keep beating around the bush. However, one senior officer did told me that, we can use it, depending on which engine has failed, and wether it is damaged or not, because if we turn on cross bleed, the damaged engine might cause foreign objects to enter the bleed system. Is this true? But if the engine is already damaged, wouldn't we have pushed the engine fire pushbutton and shut off the corresponding engine bleed valve? how is it possible then to get contamination? where can i find more info about this issue? because ive seen searching through the FCOMS and CBT but cant seem to find the answer to this
. Your comments and answers are aprreciated, thank you all in advance.
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You can use it. Nothing against it, provided you don't exceed FL limitation nor use the wing anti ice. If there is damage you will lose one pack and wing anti-ice, but the APU can supply the remaining pack, unless the affected engine is number one, in which case you cannot.
In case of terrain being an issue, such as an engine failure on a route over very high mountains where the ceiling is very close to the MEA or MORA it could be useful.
In all other cases, the remaining engine has no problem to deal with thrust and bleed.
In case of terrain being an issue, such as an engine failure on a route over very high mountains where the ceiling is very close to the MEA or MORA it could be useful.
In all other cases, the remaining engine has no problem to deal with thrust and bleed.
Last edited by Microburst2002; 21st May 2012 at 18:15.
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Hi Airmen25,
FCOM Procedures / ABN / Power Plant / Eng 1(2) shutdown,
"If ENG FIRE pb-sw pushed:
XBLEED.....SHUT"
Apparently, if the engine has suffered damage (requiring the Fire PB push) there is a chance that metal debris may have contaminated the non return function of the engine's bleed valve. Introducing bleed air to such a system would cause an undetected bleed leak, with consequent problems with pressurisation, bleed demands etc.
ECAM should invite you to open the APU Bleed valve if the APU is running and there is no engine damage.
If engine 2 was damaged, then closing the X- bleed valve would permit APU bleed air to supply Pack 1.
FCOM Procedures / ABN / Power Plant / Eng 1(2) shutdown,
"If ENG FIRE pb-sw pushed:
XBLEED.....SHUT"
Apparently, if the engine has suffered damage (requiring the Fire PB push) there is a chance that metal debris may have contaminated the non return function of the engine's bleed valve. Introducing bleed air to such a system would cause an undetected bleed leak, with consequent problems with pressurisation, bleed demands etc.
ECAM should invite you to open the APU Bleed valve if the APU is running and there is no engine damage.
If engine 2 was damaged, then closing the X- bleed valve would permit APU bleed air to supply Pack 1.
Last edited by rudderrudderrat; 21st May 2012 at 22:22.
