Pressurization / BAECS Flashcards
(41 cards)
Normal bleed air pressure
40-50 psi
Bleed air pressure check, 30 to 15 psi
Not less than 22 seconds
What systems use bleed air?
engine starting AC cabin pressurization leading edge ice protection ABSLATS
Where does the cross ship manifold extend across?
the wing front beams btwn engines 1 and 4
A bleed air duct that extends along the right side of the fuselage delivers bleed air for what?
the cargo compartment refrigeration unit and floor heat
What do bleed air compensators do? Where are they installed?
allow for expansion and contraction of the ducts caused by heating and cooling. in the longer sections of the bleed air ducts
If you close an isolation valve, are both refrigeration units lost?
No. the opposite pair of engines will drive both units.
Where are the isolation valves located?
on each wing just before the cross ship manifold enters the cargo compartment
If you close the divider valve, are both refrigeration units lost?
Allows at least one AC system to continue to operate.
Where is the divider valve located?
in the cross ship manifold between the two wing isolation valves.
What do the check valves in the bleed air system do?
Permit air flow in one direction only. Prevents air flow into an inoperative engine or the APU and loss of system pressure to the atmosphere
What do augmenter valves in the bleed air system do?
Regulate 14th-stage bleed air from the engine compressor
What does the BA/ECS do? What valves does it control?
regulates air temperature and pressure in the bleed air system augmenter valves and nacelle SOVs
Normal pressurization can be maintained with one AC, provided what else is on?
cargo underfloor heat
What does the outflow valve do in flight? on the ground?
in flight - exhausts air from the cabin at a controlled rate to maintain the desired level of pressurization on ground - allows avionics cooling discharge air to escape overboard
Where is the outflow valve located?
aft right hand corner of the flight station, behind the ACS.
What does the safety valve do?
relieves excessive positive or negative pressure to prevent damage to the aircraft or injury to personnel
What does the MANUAL VALVE CONTROL ROCKER SWITCH do?
controls the electric actuator of the outflow valve. Functional only when the pressurization mode select switch is in MAN
AUTO RATE SELECTOR What does NORM do? MIN? MAX?
NORM - provides a nominal climb rate of 500 fpm and a nominal descent rate of 300 fpm MIN - zero fpm rate MAX - 3000 fpm rate
What does NO PRESS do?
opens the outflow and safety valves and depressurizes the cabin at the rate set by the AUTO RATE selector
What does AUX VENT do?
opens the AUX VENT valves and closes the AC flow control valves and floor heat shutoff valves
What does the LDG/CONST ALT selector do?
sets the altitude of the selected landing field or the desired altitude when in the CONST ALT mode
What does the DIF PRESS indicator display?
the cabin-to-atmosphere differential pressure in inches of mercury
What does the EMER DEPRESSURE handle release?
releases the emergency depressurization door in the center overhead escape hatch
