Post by LOU on Jan 1st, 2013 at 8:07pm
The reason to close the 2 left & right bleeds is to isolate the two sides.
The #2 bleed switches are used on the ground to provide air from the APU for A/C and start air and if and engine fails or there is a bleed trip from engine 1 or 3.
The number 1 & 3 bleeds have different sub systems than the number 2 engine bleeds.
Engine 1 & 3 have a high pressure modulating valve to supply air when is at low power settings.
Normally eighth stage is used with 13th for low thrust settings.
Engine 1 & 3 have high stage available, # 2 only has 4 stage air.
Engine 2 is normally not used for bleed air to the A/C system.
Sorry for the poor quality of the screen capture.
Lou
Uploaded with ImageShack.us
The #2 bleed switches are used on the ground to provide air from the APU for A/C and start air and if and engine fails or there is a bleed trip from engine 1 or 3.
The number 1 & 3 bleeds have different sub systems than the number 2 engine bleeds.
Engine 1 & 3 have a high pressure modulating valve to supply air when is at low power settings.
Normally eighth stage is used with 13th for low thrust settings.
Engine 1 & 3 have high stage available, # 2 only has 4 stage air.
Engine 2 is normally not used for bleed air to the A/C system.
Sorry for the poor quality of the screen capture.
Lou
Uploaded with ImageShack.us