Item in the Taxi Checklist says to close number 2 left & right bleed air switches. Do we open them back at any point of taxi or flight?

Thanks,

Kris

You turn them back on after takeoff (which should be on the After Takeoff Check List). Not turning them back on leads to a pressurization warning horn when you reach 10,000 feet!

Got it! Thanks! I am exploring 727 once again... ;)

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

http://img248.imageshack.us/img248/9245/727ac.png

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Thank you for that explanation of how it all works Lou. [smiley=thumbsup.gif]



Now all I have to do is get my head around it. But...at least it's not as complex as the fuel management for the 707!!! :D ;D