View Full Version : B 737 eng bleed
Global TM
8th Jul 2005, 12:04
Can an engine be started with the engine bleed engine switch in the OFF position?
Why would you be asked this question, because the bleed air valve is signaled closed from the start valve durring engine start anyway.
Any thoughts?
GTM
IFixPlanes
9th Jul 2005, 07:56
It does not matter, if bleed SW is ON or OFF.
As you can see in the bleed schematic below, the duct to the starter is upstream of the PRSOV.
At 737NG you are right with closing signal from the (not closed) start VLV.
But at the 737CL the closing signal comes from the start SW when he is in GRD position.
B737CL
http://img209.imageshack.us/img209/8494/b737clata36eng4ew.th.jpg (http://img209.imageshack.us/my.php?image=b737clata36eng4ew.jpg)
Ingo
On the 737 200, the air for the starter passes through the bleed valve, so you need it open.
Not so on the classic and NG.
IFixPlanes
9th Jul 2005, 18:17
On the 737 200... You does not mentioned it before.
Please do it next time at the beginning.
Then i donīt waste time on things you dontīt want to know. :*
Ingo
Global TM
11th Jul 2005, 00:19
Thanks for the replies.
Happy and safe flying,
GTM