Skyblue CBT propellor control

Question 1

what is the normal takeoff power setting?

Answer 1

2475SHP

Question 2

what SHP does the automatic uptrim setting provide following an EFATO?

Answer 2

2750SHP

Question 3

what components make up the two spool gas generator?

Answer 3

a high pressure and low pressure compressor powered by their respective turbines

Question 4

how does the power turbine drive the propeller?

Answer 4

via a power turbine shaft which links to a propeller reduction gear box and then the propeller shaft

Question 5

what does the intake design ensure?

Answer 5

uniform inward flow is supplied to the compressors

Question 6

what are the 2 purposes of the S shaped design of the inlet?

Answer 6

1. FOD removal (air is lighter so it goes up to the compressors while FOD is too heavy and goes down and overboard
2. to divide the airflow into a primary flow for the engine and a secondary flow for the oil cooler

Question 7

where is the accesory gearbox mounted?

Answer 7

at the top of the engine

Question 8

what is the accesory gearbox driven by?

Answer 8

high pressure compressor shaft

Question 9

what 3 components are driven by the accesory gearbox?

Answer 9

1 high pressure fuel pump

2. oil pumps
3. DC Starter/generator

Question 10

what does the DC starter/generator drive during engine start?

Answer 10

accesory gearbox in order to accelerate the high pressure compressor rotor to the necessary speed

Question 11

what 4 components does the propeller reduction gearbox connect to?

Answer 11

1. propeller overspeed governer
2. 115 volt ACW GENERATOR
3. propeller valve module
4. high pressure pump

engine 2 also connects to the prop brake

Question 12

where is the fuel cooled oil cooler located?

Answer 12

aft of the propeller reduction gearbox

Question 13

what kind of propeller does the ATR have?

Answer 13

Hamilton Standard 568F prop which is composite

Question 14

what is the propeller driven by?

Answer 14

free power 2 stage turbine through the reduction gearbox

Question 15

what powers the free power turbine?

Answer 15

exhaust gases

Question 16

what is propeller pitch controlled by?

Answer 16

hydro mechanically controlled by a propeller valve module installed on the prop reduction gearbox

Question 17

what changes the propeller pitch?

Answer 17

oil pressure from the lubrication system supplied by a feathering pump

Question 18

how is the propeller feathered?

Answer 18

metered oil pressure is dumped

Question 19

what does each PEC control? (6)

Answer 19

1. PVM
2. Phase sync of the props
3. overspeed governor
4. autofeather system
5. alternate autofeather system
6. power and condition levers

Question 20

how does the PEC control the pitch change mechanism?

Answer 20

through 1 or 2 channels

Question 21

how does the PEC select the correct prop speed

Answer 21

PEC calculates correct pitch using altitude and speed data and prop rotation data.

Question 22

what does the PEC interface with to get altitude, speed and prop rotation data?

Answer 22

the EEC

Question 23

WHAT DOES THE PROPELLER INTERFACE UNIT DO?

Answer 23

provides interfcae between the engine controls in the flight deck and the PEC

Question 24

what `6 functions does the propeller valve module have?

Answer 24

1. speed setting
2. beta scheduling
3. propeller feathering
4. synchrophasing
5. low pitch protection
6. overspeed protection

Question 25

what 4 components make up the propeller valve module?

Answer 25

1. electro hydraulic valve 2. protection valve 3. feather solenoid 4. rotary variable differential transducer (RVDT)

Question 26

what does the electro hydraulic valve in the PVM do?

Answer 26

meters oil to the pitch change actuator and allows normal feathering of the prop

Question 27

what is the protection valve in the PVM part of?

Answer 27

overspeed, lo speed protection systems and backup feathering protection

Question 28

what is the feather solenoid a backup for?

Answer 28

the electro hydraulic valve

Question 29

what does the RVDT do?

Answer 29

adjusts and confirms the power lever angle (PLA)

Question 30

where is the prop brake installed?

Answer 30

canter shaft of the right engine prop reduction gearbox

Question 31

what does the prop brake stop?

Answer 31

the propeller and power turbine

Question 32

describe hotel mode

Answer 32

high pressure compressor rotor drives right AC generator and bleed air pressure is available downstream of the high pressure compressor to supply the packs

Question 33

when can the prop brake be engaged?

Answer 33

on the ground with blue hydraulic pressure available condition lever in feather gust lock engaged

Question 34

what must be illuminated prior to engaging the prop brake?

Answer 34

green ready light

Question 35

how does the EEC control fuel flow to the HMU to get the desired high pressure compressor speed (NH)?

Answer 35

a stepper motor

Question 36

what powers the EEC's?

Answer 36

DC EMER BUS BUS 1 AND 2

Question 37

what 4 information inputs does the EEC recieve?

Answer 37

1. power lever angle 2. power management panel selected mode 3. position of bleed air valves 4. outside conditions

Question 38

what are EEC inputs used for?

Answer 38

to calculate a new power setting before corrections are sent to the HMU stepper motor

Question 39

when the EEC button is selected off, how does HMU control NH?

Answer 39

based on position of power lever

Question 40

what does a flashing EEC fault mean?

Answer 40

a fault has occured at a power lever angle of more than 52 degrees. the power will be locked at the pre-fault value

Question 41

what should we do if we get a flashing EEC fault?

Answer 41

bring power lever into the green, This causes reversion into HMU based law. EEC can be selected off.

Question 42

what do we lose if we deselect the EEC?

Answer 42

propeller underspeed at low power

Question 43

how to power levers control fuel flow above the beta range when manual fuel scheduling?

Answer 43

via the HMU

Question 44

how do power levers control fuel flow when manually fuel scheduling below the beta range?

Answer 44

PVM

Question 45

when does flight beta range begin?

Answer 45

below 62 degrees power lever angle

Question 46

what is the ground beta range?

Answer 46

between ground idle and flight idle stops

Question 47

what do the condition levers control through a valve in the HMU?

Answer 47

PROP FEATHERING, SPEED AND FUEL SHUTOFF

Question 48

when is top law used?

Answer 48

when the the selected EEC is used

Question 49

when is base law used?

Answer 49

when the EEC is inoperative or deselected and fuel flow is determined by the PLA

Question 50

What will NH change with in base law mode?

Answer 50

ambient conditions

Question 51

what will we not have in base law mode?

Answer 51

underspeed control

Question 52

what does the underspeed control in top mode stop the NH from going below?

Answer 52

70.8%

Question 53

what mode prevents NH overspeed protection?

Answer 53

top law

Question 54

when is the NH backup law acivated in top law mode?

Answer 54

- low power settings - hotel mode - engine torque control failure

Question 55

how does top law optimise low pressure compressor operation?

Answer 55

modulation of handling bleed valve

Question 56

what are the 3 modes of propeller speed governing?

Answer 56

1. blade angle governing mode 2. fuel governing mode 3. transition mode

Question 57

what is the normal prop governing mode for flight?

Answer 57

blade angle governing mode

Question 58

in blade angle govenring mode, how is the blade modulated?

Answer 58

PVM adjusts pitch as to maintain constant speed. Available regardless of EEC status

Question 59

how is the engine managed in blade angle governing mode?

Answer 59

power management selector orders engine speed through the PEC and the Power levers command the power

Question 60

when is fuel governing mode available?

Answer 60

when the condition lever is in the auto position

Question 61

what happens in the fuel governing mode?

Answer 61

EEC increases fuel flow to maintain minimum propeller speed

Question 62

when is fuel governing mode not available?

Answer 62

when feathered or the EEC is off

Question 63

when is transition mode active?

Answer 63

on the ground in flight at low speed/power setting

Question 64

what will the prop speed be in the transition mode?

Answer 64

between 70.8% and 100%

Question 65

what are the power levers mechanically connected to?

Answer 65

the PVM and HMU

Question 66

How do the power levers control thrust?

Answer 66

through blade angle and fuel flow

Question 67

what does the pvm control?

Answer 67

propeller pitch, which regulates propeller speed (NP)

Question 68

what controls pitch change in the forward thrust range?

Answer 68

PVM

Question 69

what will the PVM do as power levers are retarded to flight idle?

Answer 69

PVM reduces blade angle to maintain selected propellor RPM as long as the condition levers are in auto

Question 70

when do the power levers acquire direct blade angle control?

Answer 70

slightly above flight idle

Question 71

what happens if prop speed drops below 70.8%

Answer 71

EEC increases fuel flow to maintain 70.8%

Question 72

what is the flight beta range?

Answer 72

FI and above

Question 73

what is the ground beta range?

Answer 73

FI to max reverse

Question 74

when is the flight idle gate unlocked?

Answer 74

as 1 landing gear shock absorber is compressed

Question 75

what does the trigger on the power levers do?

Answer 75

allows the pilot to pull the PL from the flight idle detent into the ground range

Question 76

what does the PVM do in the FI to GI range?

Answer 76

regulates power to provide speed governing in the FI to GI range

Question 77

what regulates fuel flow and prop speed in the reverse range?

Answer 77

the PVM and HMU

Question 78

what does each condition lever provide inputs to?

Answer 78

HMU and PVM of the associated engine

Question 79

when in the forward thrust constant speed range what does the condition lever set?

Answer 79

sets prop speed through input to the governor and PVM

Question 80

what engine speed is governed at the 100% overide detent on the condition lever

Answer 80

1200rpm

Question 81

how does the condition lever control propeller speed in the auto position?

Answer 81

through the power management selector position

Question 82

what is disabled with the condition lever in the feathered position?

Answer 82

propeller underspeed governing

Question 83

what does the ATPCS provide for the failed engine?

Answer 83

automatic feathering

Question 84

what 5 conditions arm the ATPCS?

Answer 84

1. PWR Management set for takeoff 2. ATPCS button armed 3. both power levers greater than 49 degrees 4. both toques greater than 46% 5. aircraft on ground

Question 85

when will automatic uptrim be disabled?

Answer 85

when power management is moved out of takeoff

Question 86

what does the AFU supply torque indications to?

Answer 86

fdau mfc flight deck indication

Question 87

what does the MFC handle during an engine failure?

Answer 87

- autofeather logic - uptrim logic - signals the effected solenoid and feathering pump - signals the uptrims

Question 88

when does uptrim occur?

Answer 88

2.15 seconds prior to autrofeather

Question 89

what is the only power management system used to restart a failed engine?

Answer 89

MCT

Question 90

what does the EEC interface with?

Answer 90

the PEC and the HMU

Question 91

what is propeller speed governed at in the 100% override position?

Answer 91

1200rpm

Question 92

how is ground idle operation permitted with the propeller feathered?

Answer 92

underspeed fuel governor is disabled with CL in feather

Question 93

how is the prop unfetahered following an engine restart in flight?

Answer 93

selecting MCT on the PWR MGT panel