18 Questions
When does the speed sensitive valve reposition to open the port for directing 14th stage air onto the bleed air valve piston heads?
Above 94% RPM
Why are the compressor bleed air valves forced closed when the engine is running above 94% RPM?
Due to increased air pressure in the 14th stage
What is the purpose of the compressor bleed surge control system during low speed operations?
To relieve excess air from the engine
What happens to the windmilling load of the front compressor when engine cranking begins?
It decreases
Which turbines drive the front compressor when the engine starts?
Second, third, and fourth stage turbines
What happens to the compressor bleed air valves when the engine is running below 94% RPM?
They open
What component consists of four pneumatically operated bleed valves located on the compressor fifth stage?
Bleed valve system
When is the speed sensing valve positioned to stop 14th stage air acting on the 5th and 10th stage bleed valves?
Below 94% RPM
What happens when the speed sensing valve is positioned to stop 14th stage air acting on the 5th and 10th stage bleed valves?
The bleed valves open
Which component responds to engine RPM in the compressor bleed valve system?
Speed sensitive valve
In the compressor bleed valve system, what ducts excess air overboard when the bleed air valves are open?
Bleed air valves
What causes the compressor air to force open the 5th and 10th stage bleed valves?
Speed sensing valve operation
What function does the compressor bleed valve system serve during engine start and up to 13,000 RPM?
Unloads the compressor
At what engine speed does the Allison T56 engine operate at low speed ground idle?
69% to 75%
What controls the opening of the compressor bleed valves during low speed ground idle or engine shutdown?
Speed sensitive valve
What happens when the operator selects the function to reduce engine speed for fuel saving and noise reduction during ground operations?
RPM is governed between 69% to 75%
How does the bleed band slacken to uncover the compressor bleed ports?
P3 air opposes spring tension
Which stages of the compressor are bled by the compressor bleed valve system?
Fifth and tenth stages
Learn about how the bleed system in compressors operates based on varying RPM levels. Understand the process of opening and closing valves to regulate airflow within the system.
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