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ATR type Rating > Skyblue CBT propeller system > Flashcards

Skyblue CBT propeller system Flashcards

(68 cards)

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1
Q

what controls the propeller?

A

PEC in conjunction with:

  • overspeed governer
  • autofeather system
  • alternate autofeather system
  • synchrophase system
  • power and condition levers
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2
Q

what does the PEH provide for the pitch change mechanism?

A

closed loop control

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3
Q

what does the PEC do if it senses a system fault?

A

detects and isolates the fault

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4
Q

how many channels make up the PEC?

A
  1. Master and backup
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5
Q

where does the PEC get airspeed and altitude from?

A

EEC

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6
Q

what does the PEC use to calculate prop speed?

A

EEC data and NP

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7
Q

how does the EEC provides overspeed protection?

A

acts on HMU to limit NH via a stepper motor

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8
Q

how does the PEC control prop pitch angle?

A

through the propeller valve module (PVM)

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9
Q

what 4 components make up the PVM?

A
  1. electro hydraulic valve
  2. protection valve
  3. feather solenoid
  4. rotary variable differential transducer (RVDT)
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10
Q

what 6 things does the PVM provide?

A
  1. basic speed set
  2. beta scheduling
  3. reversing
  4. synchrophasing
  5. prop feathering
  6. low pitch protection
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11
Q

how is blade angle controlled by the PVM in constant speed and beta modes?

A

controlled metering of oil pressure

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12
Q

how is blade angle controlled by the PVM in feather and overspeed modes?

A

dumping oil pressure

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13
Q

what is unmetred oil pressure always opposed by?

A

metered oil pressure which is then applied to the opposite side of the assembly

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14
Q

where does aerodynamic force tend to drive the prop blade?

A

to low pitch angles

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15
Q

what does the prop pitch lock ensure if oil pressure is lost from the PVM?

A

prevents aerodynamic loads reducing the blade angle by more than 1 degree

prevents speed increasing by more than 2%

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16
Q

when the power levers are in the forward thrust range, how is RPM set?

A

condition lever position sets rpm via the EHV located in the PMV via oil pressure changes

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17
Q

when in flight governing mode how is RPM set?

A

power lever angle through the PVM

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18
Q

what min propeller speed is maintained by the EEC in the ground beta/fuel governing mode?

A

70.8% NP

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19
Q

what does power lever angle command when in the ground beta range?

A

commands PVM to incrase or decrease oil pressure

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20
Q

what happens when blade angle reaches the commanded position?

A

blade angle feedback acts on the PVM to hold the blades at the new position

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21
Q

what provides torque info to the MFD, MFC and FDAU?

A

auto feathering unit

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22
Q

what provides torque info to the MFD from the power turbine shaft?

A

signal conditioning unit

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23
Q

what handles the autofeather and uptrim logic?

A

the MFC

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24
Q

What does the MFC command when an EFATO occurs?

A

commands uptrim on live engines EEC

commands oil pressure to feather the failed engine through the feathering solenoid

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25
when is ATPCS armed on the ground? (5)
1. PWR MGT to takeoff 2. ATPCS button pushed in 3. both torques greater than 46% 4. both PLA greater than 49 degrees
26
what is available when ATPCS is aremd in flight?
only autofeather
27
when is autofeather commanded?
when torque drops below 18%
28
what happens when ATPCS senses torque lower than 18% on the ground?
uptrim command is sent to EEC on unaffected engine and the live engine bleed is closed 2.15 seconds later the failed engine will autofeather
29
what happens when autofeather is triggered?
affected feather solenoid is activated and the affected feathering pump activates autofeather is inhibited on the unaffected engine
30
when will ATPCS disarm under normal conditions?
1. PWR MGT anywhere but takeoff 2. both torques more than 46% 3. either PLA more than 49 degrees 4. ATPCS button off
31
what is NP?
prop rotation speed
32
what do the 2 sensors on the reduction geartrain sent outputs to?
EEC which controls torque counter AFU which controls torque pointer
33
when will the torque pointer show amber?
100-106% torque
34
when will the torque pointer show red?
over 106%
35
what does an amber LAB under torque indication mean?
wrong EEC installed
36
what does an amber HBV under the torque indication mean?
associated handling bleed valve has failed
37
what does the FDAU calcualte and display on the torque indication?
target torque displayed in amber (or magenta on a G/A)
38
what do 3 amber xxx in the torque indication mean?
invalid PWR MGT value
39
when is NP shown in amber?
between 41.6% and 62.5%
40
when is NP shown in red>
NP above 107%
41
how is ITT sensed?
thermocouple sensros between the low pressure turbine and power turbine
42
what is the red range on the ITT gauge?
715C hotel mode 765C take off 800C in flight
43
what does a red S on the ITT gauge mean?
950C start limit
44
what is NH?
high pressure turbine RPM
45
what is normal NH range?
62-103.1%
46
what is amber NH range?
103.2-106.3%
47
when will NH show red?
above 106.4%
48
what is NL?
low pressure turbine RPM
49
what is amber NL range?
104.2-106.7%
50
what is red NL range?
greater than 106.8%
51
what does the PWR MGT supply info to?
- FDAU - PIU - EEC
52
What does the engine rating interface unit allow?
the crew to select an engine rating between the original rating and a boost rating by incraseing the thermal limit
53
when is the boost function available?
when on the ground in flight following an engine failure
54
how much is torque increased by if boost is used with PWR MGT set to T/O?
4.5% up to 4000ft and then 4%
55
how much is torque increased by if boost is used with PWR MGT set to MCT?
4%
56
when do we get an ENG BOOST caution?
when there is a disagreement between button position and the rating of the EEC's
57
when will we get an amber ENG 1 PEC caution?
both channels on the PEC have failed
58
when will we get an amber ENG 1 PEC SGL CH caution?
one of the PEC channels has failed
59
what will NP be blocked at when a PEC is turned off?
102%
60
What does the crank selection on the knob do?
motors the engine without ignition
61
what does turning the knob to start A and B do?
ignites both ignition exciter units regardless of on ground or in flight
62
what will the starter generator connect to when the START button is pushed?
either the main battery, operating generator or external power through the STARTER BUS depending on the power source
63
what des the starter generator drive during start?
the high pressure spool to an RPM of 20%NH
64
at what NH is the condition lever moved from fuel shut off to introduce fuel?
10%
65
what is self sustaining NH?
45.5%
66
what disconnects at 45.5% NH during start?
starter generator and ignition
67
what can cause a start fault?
starter gen remaining engaged past 45.5 failure of GCU prop brake on
68
what is ignition powered by?
DC ESS BUS

ATR type Rating (22 decks)

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