AIRPLANE
OPERATIONS
MANUAL
PNEUMATICS
AIR CONDITIONING
AND PRESSURIZATION
REVISION 29
2-14-05
Page
6A
Code
01
CROSS BLEED VALVE OPERATIONAL LOGIC
The Cross-Bleed Valve (CBV) receives an electrical input to open
when the following conditions occur:
− Essential DC Bus 2 is energized;
− There is no massive bleed leakage downstream of the pre-cooler or
in the Rear Electronic Compartment; and
− Cross Bleed Knob is set to OPEN; or
− Cross Bleed Knob is set to AUTO and one of the following
conditions occurs:
− Engine 2 is starting; or
− Engine 1 is starting assisted by engine 2 or external pneumatic
source (with APU Bleed Valve manually commanded to the
close position); or
− The Horizontal Stabilizer Anti-Icing System is operating
(airplanes Pre-Mod. SB 145-36-0028).
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