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t56 Flashcards

1
Q

What is the purpose of the torque meter and tie struts

A

transmit and measure torque from power section to reduction gearbox
provide alignment and rigidity

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2
Q

Major components of the torque meter and tie struts

A 
housing
torque shaft
reference shat
torquemeter pickup assy
tie struts
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3
Q

what is the toque meter housing and tie struts made of

A

steel

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4
Q

what does the torquemeter mid bearing (roller) do

A

prevents whip under high torque loadings

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5
Q

what does the torque shaft connect to

A

safety coupling on the input quill on the reduction gear box, and the compressor extension shaft

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6
Q

how many teeth does the torque meter have?

and this generates a signal for what gauge?

A

40 teeth, generate HP for the flight deck gauge

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7
Q

where are the sleeve bearings and what do they do

A

at the centre and forward end, support the reference shaft and allow the torque shaft to twist under load without affecting the R.S

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8
Q

why must you monitor the horse power gauge during high power (and under certain conditions)
and again in low power?

A

it may cause the wing and engine mount structure to become over stressed, as a result of too much power.
low power- insufficient power for safe AC operation

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9
Q

calibration of the torquemeter system and horsepower gauge is required on what occasions

A 
horse power gauge change
engine change
pickup change
after a periodic servicing 
prior to doing an engine performance run
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10
Q

what is torquemeter runout test
and when will this be performed
what device is used with a T.R test

A

when the gap between the teeth on the torque shaft and torquemeter pickup varies due to a failing pinion bearing or safety coupling

performed after a heavy landing or if engine vibrations are suspected/evident

oscilloscope

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11
Q

purpose of the reduction gearbox

A

reduce high engine rpm to a usable propeller rpm and to drive assy

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12
Q

what are the 2 stages of reduction within the gearbox

A

1st stage- spur type reduction. 3.125:1

2nd stage- planetary reduction. 4.333:1

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13
Q

what is the overall reduction

A

13.54:1

power section rpm 13820: 1021 prop shaft rpm

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14
Q

what are the main structural parts of the reduction gb

what is it made of

A 
magnesium alloy
front case
main diaphragm
rear case
rear case inner diaphragm
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15
Q

what does the front case of the reduction gearbox house

A

thrust sensitive system operating mechanism
negative torque system operating mechanism
nose scavenge pump
planetary system ring gear

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16
Q

what is mounted externally to the front case of the reduction gearbox

A

12 o clock position: upper ESU mount

3 o clock position: TSS switch

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17
Q

what does the main diaphragm of the RGB housing support

A

rear end of the propeller shaft
forward end of the input drive pinion
main drive gear
planetary sun gear

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18
Q

what does the rear case of the RGB support (internally)

and externally

A 
internally:
rear end of the input pinion
rear ends for the assy drive train gears shafts
rear case inner diaphragm
main scavenge pump

externally:
ESU (3,6,9 o clock positions)
external mounting pads for the gearbox driven assys

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19
Q

purpose of the rear case inner diaphragm

A

support the forward ends of the assy drive train gear mounts

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20
Q

components/ assys mounted to the rear face of the RGB rear case

A 
generator
engine driven compressor
pressure oil pump and filter
tacho generator
starter
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21
Q

what are the safety devices located internally on the RGB

A

propeller brake
NTS
safety coupling
TSS

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22
Q

what is the purpose of the Prop brake

A 
prevent prop rotation when feathered in flight 
-to reduce drag
- to prevent secondary damage
reduce engine rundown time
prevent windmilling on the ground
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23
Q

what is the purpose of the NTS

A

generated whenever the propeller attempts to drive the engine. mechanical mechanism that senses negative torque and transmits a mechanical signal to the prop which coarsens the blade angle until the NT ceases

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24
Q

when does the NTS operation occur on the inboard/outboard engines.
why are they different

A

inboard: -100-500 HP
outboard: -150-500 HP
due to the EDCs being fitted to inboard engines. Negative torque effort used to drive the EDCs is not sensed by the torquemeter sensor (49HP to drive EDC)

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25
Q

in an extreme setting what safety devices may be used in a negative torque situation

A

NTS

Safety coupling between RGB and power section drive

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26
Q

when will negative torque occur

A

sudden loss of power
turbulence/ wind gusts/ rain/ thunderstorms
low power settings on decent
momentary NT will occur
1) on downshift from normal RPM to low speed and
2)on engine shutdown

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27
Q

purpose of the safety coupling

A

prevent excessive propeller drag should the propeller begin to drive the engine (prop extracting energy from the slipstream)
it will automatically decouple the reduction GB from the power section whenever the NTS is unable to control the NT, & the NT exceeds -1700HP. the device will recouple itself once the NT decrease below -1700HP

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28
Q

how will you know if the safety coupling has disengaged

A

HP gauge will be reading -1000HP. HP gauge- negative indication.
May feel the asymmeteric power effect on the AC

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29
Q

what does the TSS do

A

provide an automatic means to shut down the engine and feather the prop in the event of engine power loss at high power setting. mechanically initiated and electrically activated

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30
Q

what conditions must be met for the TSS to mechanically initiate

A

autofeather system armed
power lever above 60 deg
lessthan 500lb of propeller thrust

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31
Q

when would you use TSS (normal operation)

A

usually used only for take off

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32
Q

how many thermocouples are fitted to the engine

A

18

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33
Q

why is it important that the thermocouples are indicating correctly

A

false indications of engine performance

significantly reduce life of turbine components

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34
Q

what is the H dimmension

A

the linear distance between the junctions embedded in the insulating material

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35
Q

thermocouples with a high h dimension will read …

A

under read the TIT

cause the engine fuel system to supply more fuel than actually desired

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36
Q

what is sulphidation

and what does it look like

A

accelerated oxidation of metals in the presence of sulphate ions.
“hot corrosion”

mild-whitish deposits.
serious- blistering, exfoliation

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37
Q

how can you minimize sulfidation

A

reducing low altitude flying over the sea
avoiding areas of high air pollution
fly with reduced TIT

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38
Q

what oil is used in the t56-a-14

A

mobil jet oil 2 (synthetic oil)

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39
Q

oil system operating limits
power section:
RGB:
normal oil temperature:

A

PS: 50-60 psi
RGB:150-250 psi
normal oil temp: 60-90 deg

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40
Q

what is the purpose of the power section pressure filter check valve

A

prevent the contents of the oil tank draining down into the engine when it is stationary

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41
Q

what is the pressure adjusting valve in the oil system

A

in the event of an oil passage or jet becoming blocked, the oil pressure will rise indicating a blockage has occurred.

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42
Q

what types of RGB oil pumps are there

A

main scavenge pump- driven from the assy gear train
nose scavenge: driven from the prop shaft
pressure pump- gear type

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43
Q

oil sump components

A

shut off valve
electrically actuated

drain rooster/ cock

temperature bulb
this is in the position of the “coldest” oil in the QEC

temperature switch
located at the outlet. illuminates when the switch reaches 100*C

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44
Q

oil scavenge system components

A 
external scavenge filter
fuel heater strainer
oil cooler
EDC oil cooler
oil cooler augmentation piccolo tubes
oil cooler flap
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45
Q

sources of bleed air

A

engine
auxiliary power unit
ground air supply cart

46
Q

systems which use bleed air

A 
compressor bleed valve
engine air inlet housing and intake scoop anti icing
engine starting
oil cooler augmenting
wing anti icing
bomb bay heating
AMP
47
Q

purpose of the bleed air check valves

A

prevent reverse flow of bleed air, from other sources, passing into the diffuser when the engine is stationary and/or during engine starting

48
Q

what valve supplies bleed air to, and modulates the control of, the engine starter

A

engine start control valve

49
Q

engine bleed air systems which are not supplied from the QEC bleed air manifold or AC bleed air manifold are

A

AIH anti icing system
air inlet duct anti icing system
engine compressor bleed valves operation
these systems are connected directly to their respective engine diffuser

50
Q

what is a compressor stall

A

the higher pressure air in the combustion section flows forward through the compressor and exists out the engine intake. the pressure in the combustion section is quickly dissipated, the compressor again begins to pump air normally through the engine and the cycle repeats

51
Q

what overcomes compressor stall (component)

when would you use them

A

8x bleed air valves around the 5th and 10th stage compressor are dumped.
these are open from 0-94%
during starting, acceleration and slow speed running

52
Q

what component is responsible for porting 14th stage bleed air onto the bleed valves (opening and closing them at 94%)

A

speed sensing valve

53
Q

what positions are the igniter plugs location at

A

2 and 5

54
Q

when carrying out any maintenance on the ignition system, the fuel shut off valve must be pulled. why

A

the fuel and ignition control cb will not isolate the syem

55
Q

major components of the starting system

A

engine starter (airesearch air turbine type)
start control valve (mushroom tophat)
geneva loc

56
Q

Engine identification of the t56

A

T-turboprop
56- designation of the engine
A-manufacturers name
14- model no of the designation

57
Q 
ESHP-
100% RPM-
Reduction ratio-
Prop speed-
TIT-
Max start-
A 
4910
13,820
13.54:1
1020.6
1077(1083)
830-850
58
Q

Oil publications

A

Fols
Flight manual
F700
Ss&rps

59
Q

Normal rpm
Low
Takeoff
Flight idle

A

96.3-99.1
71.0-73.8
99-101
94.5-98.4

60
Q

Basic engine is made up of

A

Power section
Torque meter and tie struts
Reduction gearbox

61
Q

Parts that make up the power section

A

Compressor
Combustion
Turbine
Assy gearbox ???

62
Q

Things attached to the outer surface of the AIH

A 
12-Engine breather
3-Anti ice valve
6-Assy gb 
7- no 2-4 oil outlet
8- fcu probe
9- anti ice valve
10- no 1 bearing labyrinth seal vent
63
Q

6 o clock strut of the AIH has additional passages for

A

Assy gb driveshaft
Pressure oil to the inner casing
Scavenge oil from the inner casing to the assy gb
Venting air to/from assy gb

64
Q

Where is the diffuser located

Purpose of the diffuser

A

Between compressor section and outer combustion case. Forward of the engine firewall

  • Directs compressor discharge air into the combustion section
  • Provides mounting lad for 6 fuel nozzles
  • Mounting point for the rear engine mounts
  • Bleed air tap off for the AC pneumatic systems
65
Q

Major components of the combustion section

A 
Outer and inner combustion casing 
Inner combustion casing liner 
6 combustion cans
Turbine coupling shaft
Lighthouse cavity
66
Q

What things support/ hold up the combustion cans

A 
Liner supports
Fuel nozzles
3 thermocouples
1st stage nozzle guide babes
Cross over ducts(where the flame is propagated from)
67
Q

What do tangential struts do

A

Compensate for the heat expansion to ensure inner shell stays concentric with the outer shell to prevent turbine rub

68
Q

How is the assy gb driven

A

Compressor extension shaft down the 6 o clock strut of the AIH

69
Q

What components are driven off the assy gb

A 
Fcu 
External scavenge pump 
Fuel pump cluster
Speed sense valve
Speed sense control
Main pressure and scavenge oil pumps

Chip detector
External vent
Power section pressure oil filter

70
Q

Purpose of the propeller brake

A 
Prevent prop rotation when feathered 
Reduce drag 
Prevent secondary damage 
Reduce engine rundown time
Prevent windmilling
71
Q

What are the 3 operating positions of the prop brake

A

Released:>21%
Engine started is operating.

Applied: <21%

Locked: whenever prop is turned in locked position

72
Q

Planetary and spur gear reduction ratio in the rgb

A

Spur- 3.125:1

Reduction-4.333:1

73
Q

How does the prop brake “hold”

A

As engine rpm increases, rgb oil pressure rises and at approx 21% the oil pressure is sufficient in the cylinder within the outer cone to hold the brake released even when the starter is disengaged

74
Q

What is the priority for engine auto feather when tss is used and why

A

4,1,3,2

Gives priority to the outboard engines as they have an asymmetric effect on AC

75
Q

Prop rotation
Turbine rotation
Compressor rotation
Combustion can identification

A

Clockwise
Anti
Anti
1 at top, clockwise

76
Q

Basic engine-
ESU-
QEC-

A

Basic:
Power section
Torque meter and tie struts
Rgb

ESU:
Cowlings and support structure
Intake ducting
Structural mounting (engine)
Structural braces (airframe)

QEC:
Basic engine
ESU

77
Q

Power section made up of

A

Compressor
Combustion
Turbine
Assy gb

78
Q

Purpose of the air inlet guide vanes assy

A

Reduce fod

Direct air onto the first stage of the compressor at the correct angle

79
Q

Where does the no 1 labyrinth seal get it’s pressurised air from

A

6th stage compressor air

80
Q

How does air escape after it has leaked past the no 1 bearing labyrinth seal

A

Forward face of the compressor rotor and joins the air flow onto the compressor
Through the engine breather
Scavenged with the oil returning to the assy gb (6 o clock strut)

81
Q

When will you do a torque meter runout test

A

Suspect engine vibrations

Heavy landing

82
Q

oil is ported into the AIH 6 o clock strut and into the AIH inner casing to lubricate what

A

No 1 bearing
Compressor extension shaft bearing
Side gear and bearings
Torque meter mid bearing and mid sleeve bearing
Port oil down the lower lh strut of the AIH

83
Q

major components in the engine starting system

A

engine starter
start control valve (mushroom tophat)
generva loc(fcu fuel shut off valve)

84
Q

engine starting air is supplied from

A

another engine
apu
ground cart

85
Q

why do we have oil cooler augmentation tubes

A

when props are positioned between ground idle and max reverse, the blades are at negative angles. no air is directed in the oil cooler intake duct.
under these conditions, oil temp can exceed allowable temp (100%)

86
Q

what are the 2 anti icing systems that utilize the 14th stage bleed air

A

AIA antiicing

air inlet duct anti icing

87
Q

what areas and components of the AIH are heated

A

leading edge of the 8 radial struts in the AIH
each vane of the compressor inlet guide vane assy
fcu temp sensing probe shroud
upper half of the torquemeter shroud

88
Q

what will happen when you use the anti icing system

A

TIT rise of approx 20*C

200-300HP drop

89
Q

2 separate mechanical control system for each engine

A

power lever

e handle

90
Q

when the E handle is pulled… what happens (mechanically)

A 
mechanically operated systems: 
fuel shut off at FCU
fuel shut off at wing beam
generator blast duct cooling air shut off
prop feathers
91
Q

when the E handle is pulled… what happens (electronically)

A 
fuel shut off at fcu
oil shut off at oil tank sump outlet
dumps edc pressure overboard and closes edc firewall shut off valve 
bleed air shut off at engine firewall
prop feathers
92
Q

what is the coordinator

A

coordinates power level and e handle operation to the fcu and prop
provide a power lever position/TIT reference signal above 66* coordinator position

93
Q

where are the fire zones and the temperature

A

zone 1:QEC, 600*
zone 2: forward of the firewall, 400*
3: wheel well, 400

94
Q

fire extinguishing bottles contain ___ and are pressurised to ____

A

10.5lbs halon (BCF)
nitrogen, 600 psi
high rate discharge. discharges within 0.4s

95
Q

how many fire bottles are allocated to an engine, and how do you fire them

A

2 bottles per wing.

each engine is allocated a bottle, however a second bottle for the adjacent engine, can be transfered

96
Q

can you transfer fire bottles between engines

A

yes, on the same wing only

97
Q

flight deck fire indications

A

steady red light illumination surrounding e handle
audible horn in flight deck
audible horn in tac station(only if ac if on ground)

98
Q

areas of electrical power supply components

A

generators
main load centre
forward load centre

99
Q

generators are only available if

A

generator switch is on
engine is at normal rpm
apu is over 95%

100
Q

how do you convert _Ac to _dc

A

tru
115VAC to 28VDC
are you a tru ac/dc fan

101
Q

how do you convert dc power to ac

A

inverter

102
Q

Reduction gearbox oil pressure is the result of

A

Oil viscosity
Volume flow
Restriction to flow

103
Q

Oil tank
Usable:
Unusable
Air foaming space

A
  1. 65 us gallons
  2. 4 US gallons
  3. 7 us gallons
104
Q

Sources of venting/breathing air into the engine breather unit

A

1) 12 o clock strut of AIH
Reduction gb through torque meter
Assy gearbox through 6 o clock strut

2) External flexible tubes
1 bearing labyrinth seal
Assy gb
Oil tank pressurising valve

105
Q

Why will the flight deck show a increase of TIT if the augmentation is satisfactory
(Oil cooling system)

A

Fuel system is in temp limiting, there is less compressor air for the same scheduled fuel

106
Q

What are the bleed air passages/areas for the AIH

A

8Leading edges of AIH
Inlet guide vanes
Torque meter shroud via external hose
fcu temp probe shroud

107
Q

2 anti icing engine systems

A

AIH

Inlet duct

108
Q 
Throttle positions
Max reverse 
Ground idle
Ground start
Flight idle
Crossover
Take off
A 
In degrees 
0
9
15
34
66
90
109
Q 
Throttle ranges 
Ground range
Flight range 
Temp limiting 
Temp control
A 
In degrees
0-34
34-90
0-66
66-90
110
Q

Mechanically operated systems when e handle is pulled

A

Fuel shut off at fcu
Fuel shut off at wing beam
Generator blast duct cooling air shut off
Prop feather valve

111
Q

Electrically operated systems when e handle is pulled

A 
Fuel shut off at fcu 
Oil shut off at tank sump outlet
Demos edc pressure overboard 
Bleed air shut off at eng firewall
Prop feather
112
Q

Mechanical inputs and outputs to the coordinator

And electrical output

A

Input
Power lever
E Handle

Output
Prop control
Fcu fuel scheduling
Fcu shut off

Electrical outputs
66degree microswitch
1000 ohm potentiometer

PPL (7 decks)

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