11.16 - Pneumatic/Vacuum Flashcards
What are the safety precautions before connecting a ground cart to an aircraft? (2)
- Make sure the electrical system is energised to prevent pneumatic operated systems starting unwanted or unprotected
- Don’t use cold pneumatic air or icing of turbines and valves may occur.
What is used to cool bleed air from the engine before it goes on to the system?
Fan air is used to cool pneumatic bleed air before it goes to the different pneumatic systems.
Why should you not put cold pneumatic air into pneumatic systems from a ground cart?
Icing of turbines and valves may occur
Which warning light comes on when a pneumatic duct ruptures?
'’PNEUM MANF FAIL’‘ - This warning light comes on, if a duct ruptures or a leak in a pneumatic system is detected.
From what parts of the engine is pneumatic air taken from?
- Low Pressure (LP) stage is used when engine RPM is high (cruise)
- High Pressure (HP) stage is used when engine RPM is low (Idle power or descent)
(c) To split or connect the different pneumatic systems
(b) The Fan Air Valve
(b) Fan Air
(c) The engine HP or LP compressor stage
(c) To determine the source of engine compressor stage
(b) Pneumatic operated systems may start unwanted or unprotected
Oil from the discharge of a wet-type air pump is collected by a/an ________ and returned to the engine
air/oil separator
The vanes of a dry type air pump are made of ______
carbon
Another name for a ‘water trap’ is a ______
moisture separator
What is the difference between ‘‘wet’’ and ‘‘dry’’ engine driven pumps?
'’Wet’’ pumps have steel vanes that are lubricated and sealed with engine oil drawn in through the pump mounting pad and exhausted with the discharge air. This oil must be removed with an air-oil separator before the air can be used to inflate the deicer boots and drive instrument gyros.
'’Dry’’ pumps have vanes made of carbon that don’t need lubrication. They are used so no oil is the the discharge air, however the problem is the carbon vanes are breakable.
Why should you not put cold pneumatic air into pneumatic systems from a ground cart?
It may lead to ice forming in turbines and valves which can damage them and cause leaks.
What is used to monitor pneumatic air temperature?
(Fan air valve) -controls it
Temperature Sensors mounted all along bleed air manifold
In what position is the isolation valve normally in during flight and why?
(Pneumatic System isolation valve)
The isolation valve is normally closed during flight as each engine supplies it’s own bleed air manifold.
Apart from Bleed air how else might pneumatic air be generated for aircraft use?
Through the APU or an external air supply such as a ground pneumatic cart or network.
What is used to cool bleed air from the engine before it goes on to the systems?
Fan air is the cooling medium in a heat exchanger before bleed air from the engine goes to any systems.
The high pressure control valve is ___________ and ________ actuated
The high pressure control valve is electrically controlled by solenoids or a torque motor and pneumatically operated/actuated.
The ________ regulates the amount of cooling airflow via the heat exchanger to control the required pneumatic temperature.
Fan air valve
The fan air valve is normally ______ actuated and _____ controlled
The fan air valve is normally pneumatically actuated and Electrically controlled by a shutoff solenoid or a torque motor, depending on the aircraft type.
Why would the following warning come on:
'’PNEUM TEMP HI’‘
This warning light comes on, if the pneumatic temperature exceeds a value (255^C)
