Learjet 35 PTM Chapter 9 (Pneumatics) Flashcards
Where is the low pressure air and high pressure air taken from inside the engine?
LP: The fourth stage axial compressor
HP: The centrifugal compressor
What is the pneumatic air used for on our airplane?
Cabin pressurization
air conditioning
anti-icing systems
hydraulic reservoir pressurization
What is the biggest difference between the early pneumatic system and the current one?
The current pneumatic system includes the installation of emergency pressurization valves
When you pull an engine fire pull T-handle, it cuts off bleed air, However it does not cut off __________________ in order to pressurize the alcohol tank, power the H-valve, etc…
HP Bleed Air….
But, the engine dies anyways, so this is kind of useless information.
What is the purpose of check valves in the bleed air system?
Check valves are installed in the bleed air ducting from each engine and allows airflow in only one direction. This is important because it prevents loss of bleed air during single engine operation.
What things does the high-pressure servo air supply power to?
Controls the position of the hot air bypass valve (H-valve)
Modulates the flow control valve
Operates the pressurization jet pump
Controls position of the emergency valves
How do you activate the emergency pressurization in early model aircraft?
1. Push the IN-NORMAL/OUT-DEFOG knob in,
2. Position the WSHLD HT AUTO-MAN switch to AUTO
What are the four ways emergency pressurization activates in current model aircraft?
1. By positioning a BLEED AIR switch to EMER
2. Cabin altitude exceeds 9500 +- 250 ft
3. Loss of DC electrical power
4. Loss of HP servo pressure
If you have a full electrical failure, what will happen to the pressurization system?
This will cause the emergency valves to open and you will have very hot air coming into the cabin.
