Pnumatics Flashcards
Where do you find pressure reg valve
(Engine bleed valve) upstream of pre cooler
Where does bleed air come from
Engine compressor
What is the pneumatic bleed air used for
Air con , engine start , and resivouirs
Purpose of pneumatic controllers
Monitor pressure temp , register leaks , monitor operation of pneumatic controllers
How many pneumatic controllers for each engine bleed system
1 per engine
How is pnuematic vaccine pressured on ground
Via high pressure ground connectors
What’s the pressure in most systems
45psi
What type of valve is the bleed
Butterfly type valve , spring loaded
What does check valve do
Prevent back flow
What the purpose of pre cooler
Cool engine bleed air temperature
What does the fan air valve do
Allow more or less fan air to pass through pre cooler
If the mass of air is constant what effect does it have on cooling effect
It is constant as well
What does the pre cooler cooling effect depend on
Mass and temp
How are pneumatic ducts monitored
Leak detection system
How is control of pnuemanic system achieved manually
Control panel in cockpit
How is control of pnuematic system achieved automatically
Pnuematic controller
Where is bleed valve operated manually
Switch in cockpit
What measures temp in bleed valve
Thermostat
Where is thermostat located
Downstream of pre cooler
What does bleed valve do
Main part which regulates bleed air from engine
When is reverse flow through bleed valve allowed
Only during engine start
When is over pressure valve closed
85psi
What monitors temp reg pre cooler
Temperature sensor
What happens when there’s a malfunction on the temperature regulator pre cooler
System fault which is illuminated on bleed panel in cockpit
Where is air taken while operating at low speed
High stage of engine compressor
When does the hp valve open
When pressure from ip stage not sufficient to meet requirements of pneumatic system
When does hp valve close
Pressure of hp reaches pre determined value
What are the alternate air sources
Apu air supply and hp ground supply
How is ground supply connected
3 inch ground connectors
What the purpose of cross bleed valve
Connect or isolate two parts of bleed air system
How is cross bleed valve operated
Motor operated as it’s commanded to open and close
Cross bleed valve position
Usually closed
What’s the result of a leak in air duct
Overheat
What happens after a leak in air duct is detected
Engine bleed air system is shut off automatically via pneumatic controller or manually
