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29 Cards in this Set
- Front
- Back
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What are the services of the pneumatic system? |
Aircon, cabin pressurization, engine and airframe anti-icing, engine starting, hydraulic reservoir pressurization, potable water pressurization, total air temp probe |
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Where is air supplied from? |
Hp2, hp6, Apu, three ground connections (huffer cart) |
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What does the 'Duct Leak' light indicate? |
Overheat detector attached to full length of pneumatic ducting to detect temperature change outside of ducts |
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What does the 'Bleed' light indicate? |
Respective engine bleed overheat and system shutdown |
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What does the 'Hi-stage' light indicate? |
Respective engine bleed over pressure and Hp6 shutdown |
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What does the valve light indicate? |
Position disagreement |
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When does hp2 work compared to hp6? |
Hp2 provides majority of flow at normal operation of engine (climb/cruise). Hp6 kicks in when engine output is reduced (lower engine rpm). Can change between both dependant on conditions, altitude, demand etc |
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What source provides air to the engine anti icing? |
Hp2 air only |
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What is the purpose of the hspov |
To shut off high pressure (hp6) when intermediate pressure (hp2) has enough pressure to meet requirements |
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When is the HPSOV commanded open? |
When duct pressure sensed upstream of hpsov is below the preset 'switch over point' then hp6 air is used |
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What is the switch over point based on? |
Required engine output to support air supply system demands using hp2 bleed pressure |
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What is the altitude switcher solenoid for? |
When an altitude of 31000ft the hp6 air availability is reduced to protect the engine against surges at low rpm at high altitudes |
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What happens during an over pressure? |
When pressure exceeds 125-135psi the system will shut down and can only be reset on ground. |
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What is the output temperature? |
360-400 degrees Fahrenheit |
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Is the precooler sring loaded open or closed? |
Open. Pneumaticslly closes in response to a temp sensor downstream |
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Prsov controls pressure between what values? |
40-53psi |
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How does the prsov control temperature? |
There is a sensor installed downstream to bleed control pressure away and modulate the valve towards close to perform a temp limiting function. Modulation starts at 450f and will fully close at 495f. |
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What would indicate a overheat condition? |
Low output pressure and if left system is involved, lower flight deck temperature |
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How is reverse flow monitored? |
A reverse flow check controller- differental pressure switch. If downstream (of the prsov) exceed the upstream of more than 0.37psi. Then the prsov and hpsov are commanded closed until negative pressure situation fixed |
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What is the isolation valve? |
Essentially divides pneumatic system in two. Used during engine start |
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How many ground connections are there? |
3 total. 2 left, 1 right |
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Apu bleed control |
Supplies air to pneumatic system on ground and upto 19000ft. Has a valve thay is only open close, does not modulate. |
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What electronic interlocks are in place to prevent operation of apu bleed so it does not interfere with normal pneumatic operation? |
Apu must be at 95% rpm, left engine fire and apu fire switch unarmed, left prsov closed, either right prsov or isolation valve closed |
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When does the temp limiting function of the prsov kick in? |
450-495f |
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If all other temp controls fail,and temp reaches 490f, what else is in place? |
2 temp switches will shut respective engine bleed system by closing both prsov and hpsov. Bleed light will come on and can be reset by cycling on off switch after temp drop |
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What are two ways to read the pressure of the pneumatic systems? |
Eicas and dual needle indicator |
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What slats are affected by anti icing? |
2,3,4 7,8,9 |
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How long will the ground test of the thermal anti icing last? |
12 seconds for the valve light to go off/on |
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What is the hs pilot for? |
Controlling flow of the hp6 bleed air |
