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34 Cards in this Set

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What do the compressor bleed air valves do?

are on the 10th stage of the compressor. the help in preventing stall or surge by controlling the air bleed during start and acceleration. They close after the engines start
what is the compressor start bleed control valve.

located on the aft anti icing tube at the diffuser housing, it controls 14th stage air pressure applied to the top area of each upper and lower compressor air bleed valves

What does the CVG actuator do?

changes compressor stator vanes 1-5 to assist in power control. controlled with high pressure fuel from the FPMU
How many stages of reduction are in the PGB?


What 5 components mount onto the GMAD?

AC Generator, hydraulic pump, PCU, OSG (high pressure pump), PGB lube and scavenge pump
What connects the PGB to the engine?

The torquemeter. There are also 2 struts that provide structural support
What are the primary functions of the PGB?

Transmit shaft power from the torquemeter to the prop, reduce shaft rpm, and supply shaft power to the GMAD gear train

What are the ratios of reduction in the pgb?

first stage is 3.226:1

second stage is 4.333:1

total of 13.98:1

What are the primary functions of the torquemeter assembly?

transmit engine output power to the pgb, adds stability from engine to pgb, supplies calibrated torque reference to the fadec

What 4 components make up the torquemeter assembly?

The torquemeter shaft, reference shaft, the housing, and anti-icing shroud
What is the Compressor?

14 stage axial flow with one (inlet guide vane) IGV and 5 stages of (compressor variable geometry) CGV

What is the air inlet housing?

Primary structural units of compressor. aluminum alloy with 6 radial struts to allow anti icing air to flow through. the bottom strut is the opening for the radial drive bevel pinion gear shaft that drives the PUAD

What is the compressor case?

holds the compressor rotor. bolts to air inlet housing and diffuser. has an integral bleed air manifold at tenth stage.

what does the tenth stage bleed air manifold do?

collects air at the tenth stage that bleeds out of the engine through the compressor start bleed control valves during engine start. Also supplies heated pressurized air for the aircraft to use
What is the purpose of the combustion liner?

it is where ignition and combustion take place. There are 16 ports for the fuel nozzles and 2 for the igniters. the annular combustion liner is cooled by effusion cooling(many tiny holes in the liner wall that make a "cooling blanket" that protect the liner from the combustion gases)
what does the turbine do?

Takes the energy of the flowing gases and mechanically turns the turbine using shaft power. it is 4 stages. stages 1 and 2 drive the compressor while 3 and 4 supply the power to turn the pgb and the prop.
What does the PUAD do?

mounted on bottom of forward end of compressor air inlet housing. supplies mounting flanges for FPMU, alternator stator, starter, and p/s lube and scavenge pump, and brackets for FCOC
What does the FPMU do?
It acts as the interface between the FADEC and the fuel nozzles. Run by the FADEC and mounted on the PUAD, and it pumps, filters and meters fuel, provides fuel filter bypass indication, and moves the CVG actuator.
describe the pump in the FPMU

There are 2 pumps. The first element is a low pressure centrifugal pump. It raises the pressure of incoming fuel to meet op req for the high press gear pump

explain the fuel filter in the FPMU

it has 2 bypass filters and 1 bypass valve. The valve opens at 19-20 psi
What is the primary source of power for the FADEC

Alternator Stator. However, the aircraft 28VDC Power supply powers FADEC until engine rpm is sufficient enough to take control
How many fuel filter bypass indicators are there?
The are 2, an actual and an impending.
How does the fuel flow work?

goes from tank to FPMU, goes through the first stage low pressure centrifugal pump, then to the FCOC. Then goes pack to the FPMU into the fuel filter, then through the high pressure gear pump. then the flow wash filter and metering valve. goes through the mass flow sensor to the left and right fuel manifolds, and then to the nozzles.
What does the Alternator Stator supply power to?

The FADECs and the ignition system.
What is the alternator stator output?

20-40 VAC
What is the purpose of the exciters?
convert the power from the stator into the high energy needed for ignition.

How many sparks can the exciters create?

4-7 per second
When does the alternator stator supply the 20-40 VAC to the exciters?

When the engine is more than 10% Ng (gas generator speed)
what is the anti icing air valve controlled by?

the NIU
Why would the anti icing air valve be energized in the closed position?

if you lose power to it, It is deenergized open so that way you always have access to anti icing air

What does the anti icing air valve supply 14th stage bleed air to?
the air inlet housing struts, igv, cip sensors, it sensors, torquemeter, nacelle air inlet scoop, and the nacelle oil cooler scoop
what are the CIT sensors and how many are there?

there are 2. they sense the air temp before it reaches the compressor. they send the signal to the fadec so it can correct the power settings due to the ambient air temp
what are the CIP sensors and how many are there?

three are 2. mounted at 12 oclock on the air inlet housing, they measure inlet pressure, and send the info to the fadec to control engine functions