systems Flashcards
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What are the sections of the engine?
Cold
Hot
Accessory
Power Turbine
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What are the two mechanical inputs to the HMU?
PAS (power available spindle, connected to PCLs)
LDS (load demand spindle, connected to collective)
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Functions of HMU
Pumps fuel at high pressure
Meters fuel to ODV
NG and fuel flow limiting
Positions variable guide vanes
Positions start bleed valve
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Oil Tank Capacity
7 US Quarts
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How does the oil cooler work?
Oil is cooled by transferring heat from the oil to the fuel.
Liquid to liquid.
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Functions of ODV
Primes/sends fuel to main fuel manifold
Purges fuel from main fuel manifold on shutdown
Shuts off fuel when NP Overspeed sensed by EDECU
Shuts off fuel when Hot Start sensed by EDECU
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When does the impending bypass indicator thermal lockout engage?
Below 38 degrees C
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Engine Alternator Functions
Ng signal to the cockpit
Power to ignition exciter
Power to EDECU
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Engine A/I One Q loss per engine
20%
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At what NG does the engine anti-ice start bleed valve close?
88-92% NG
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Engine Inlet Anti-Ice System
When will the advisory illuminate?
When the inlet temperature reaches about 93 degrees C.
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Engine Inlet Anti-Ice System
How is the system controlled?
By ambient sense port.
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Engine Inlet Anti-Ice System
Temperature Ranges
Above 13 C - illumination of advisory indicates a system malfunction.
Range 4-13 C - may or may not illuminate
At 4 C and Below - failure of advisory to appear in flight indicates a system malfunction
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Engine anti-ice and engine inlet anti-ice valves failing to the open position power reduction.
Up to 20% Q per engine.
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What drives the compressor?
Gas generator turbine
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What is the Power Turbine connected to mechanically?
High Speed Shaft
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How many stage compressor?
Five stage
During engine start, when will ignition stop?
Either the ignition key lock is turned OFF or starter drops out
What type of ignition system do we have?
non-continuous
AC powered
capacitor discharge
low voltage
What kind of starter do the engines have?
Pneumatic
What three sources are there for engine start?
Crossbleed
APU
Ground source
Describe valves during a crossbleed start
Air SRC switch - ENG (both engine cross bleed valves will open
Pressing start button for engine not operating - start valve opens, cross bleed valve closes
What are the two LRBs on each pump for? What do they do?
Pressure filter
Return filter
They protect the pump from high pressure in the return system, they will pop when pressure is exceeded.
What is the depressurizing valve in the backup pump module for?
It reduces the output pressure of the pump upon startup of the electric motor. It unloads the electric motor by reducing torque requirement at low RPM. Reduces the current demand during backup system startup.
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Built-In Forward Tilt
3 Degrees
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Freewheel Unit Definition
Allows engine disengagement during autorotation, or in case of an inoperating engine, the accessory module will continue to be driven by the main rotor.
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Transmission Accessory Module Definition
Provides mounting and drive for an electrical generator and a hydraulic pump.