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T-6: Systems 1 > SYS103 - Propulsion 1 > Flashcards

SYS103 - Propulsion 1 Flashcards

1
Q

What are the three labeled PCL positions?

A
  • MAX
  • IDLE
  • OFF
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2
Q

What are the components of the ignition system?

A
  • Ignition exciter
  • Two high voltage igniter cables
  • Two spark igniters
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3
Q

What is the low pitch propeller pitch condition?

A

The propeller blades are approximately 15 degrees from the perpendicular plane. The blades produce some thrust and the most amount of drag. The propeller will be in this position during low speed and low throttle flight.

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4
Q

What is the PMU and what is its pupose?

A

The PMU is the Power Management Unit and is a computer unit located underneath the engine in the accesory compartment. The PMU pocesses power requests from the PCL and keeps the engine and prop within operating limits

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5
Q

How does the pitch change mechanism work?

A
  • The pitch change mechanism uses the oil system to force the propeller blades away from feather.
  • The oil for this system is provided by the engine oil systema nd regulated by the PIU
  • As the PIU increases oil pressure, the sliding piston is forced foward, rotating the propeller blades toward a lower pitch.
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6
Q

What is the cause of a IGN SEL annuicator illumination?

A

The igniters are activated.

  • If the igniters are activated, then the ignition switch is either:
    • Set in the NORM position and the start switch is moved to AUTO/RESET

– Set in the ON position

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7
Q

How is propeller RPM measured?

A

Propeller speed (Np) is measured by a phase shift torque probe located in the reduction gearbox. Data from this torque probe is continually monitored by the PMU.

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8
Q

What is the effect of having the ignition control switch in the ON position?

A

The igniters will operate continuosly

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9
Q

How does the pressure pump pressurize the oil during normal and aerobatic flight condiitons?

A

The are two pickups inside the oil tank.

Normal: The first pickup is located in the center of the oil tank and is submereged in oil during normal flight operations.

Aerobatics: A second pickup is located near the top of the tank and ensures constant flow of oil during inverted/areobatic flight.

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10
Q

How are the front and rear PCLs connected?

A

They are connected by a push-pull rod, providing identical control of the propulsion system from either cockpit

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11
Q

What does this combination of annunciator illumantaion mean, and what do the MASTER WARN and MASTER CAUT do?

A

The PMU is nonfunctional. The PMU fail light is always accompanied by the PMU status. An aural tone is heard and the MASTER CAUT and MASTER WARN lights flash.

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12
Q

During autostart or normal operations, the ignition control switch should be placed in what position?

A

NORM

{{16 1 0.png}}

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13
Q

What is the purpose of the oil cooler?

A

It cools down the scavenged oil before returning it to the oil tank.

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14
Q

How do you measure the propeller pitch angle?

A

It is the angle between the plane of rotation and the chordline of the propeller blade.

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15
Q

Describe how the PCL controls Fuel Management Unit (FMU)

A

PCL movement physically moves the input lever on the side of the FMU. This fuel request displaces a cam in the FMU which releases the requested amount of fuel.

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16
Q

What is the high pitch propeller pitch condition.

A

It is a condition inbetween feathered and low pitch and is the most commonly used pitch condition.

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17
Q

What is the purpose of the Power Control Lever (PCL)?

A

Controls fuel flow to the engine, producing torque on the propeller, and ultimately controls the amount of enginer power and aircraft speed.

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18
Q

How does the ignition exciter work?

A

The ignition exciter recieves a low voltage input signal and transforms it to a high voltage output signal.

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19
Q

What type of engine does the T-6A have?

A

Pratt & Whitney PT6A-68 free turbine, reverse flow, turboprop engine

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20
Q

What is the effect of having the ignition control switch in the NORM position?

A

The igniters initate when the starter switch is set to AUTO/RESET. The PMU energizes and de-energizes the igniters as required during the start sequence. A greeen IGN SEL annuciator illumantes when the igniters are activated.

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21
Q

What are the components of the gas generation section?

A
  • Compressor inlet
  • Compressor
  • Combustion chamber
  • Compressor turbine
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22
Q

What are the components of the power turbine section?

A
  • Power turbines
  • Exhaust case
  • Reduction gearbox
  • Propeller shaft
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23
Q

What are the contents of the Oil System?

A
  • Pressure System
  • Scavenge System
  • Cooling System
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24
Q

How does the starter turn the compressor?

A

Via a linkage in the accesory gearbox.

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25
Q

What does the PROP SYS battery bus circuit breaker power?

A

The feather dump solenoid valve.

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26
Q

What happens to the propeller pitch if oil is lost and there is residual oil pressure from windmilling?

A

The PIU will still attempt to maintain the current propeller pitch since there is still oil pressure. The propeller still needs to be feathered and this is done by putting the PCL into the OFF position. This releases the oil pressure by activates two separate control valves within the PIU

  1. A microswitch activates the solenoid valve.
  2. Second valve releases oil pressure controlled by the PMU

Oil pressure being released by either valve allows for the prop to feather.

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27
Q

What are the three propeller pitch conditions?

A
  • Feathered
  • High Pitch (coarse)
  • Low Pitch (flat or fine)
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28
Q

When is the OFF PCL position used?

A

During engine shutdown

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29
Q

What does it mean if this annunciator illuminates?

A

The chip detector system has deteced metal particles in the oil system. This chip detector is located in the reduction gearbox and is warning you that there is the possibility of gear damage.

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30
Q

You are in flight and this annuincator illumantes, what does it mean?

A

The amber PMU status annunicator in flight indicates that there is either of, or a mistach between the weight-on-wheels switches, this alerts you the pilot that the PMU will not revert to ground mode upon landing.

31
Q

What type of propeller does the T-6A use?

A

An aluminum 97-inch, four blade, constant speed, variable pitch, non reversing, feathering propeller.

32
Q

As gas exits the exhaust stack, it does not affect the amount of thrust produced (T/F)?

A

False, the exhaust gases provide a small amount of thrust.

33
Q

How does the T-6A illuminate an oil pressure and temperature annunciator?

A

Th oil pressure and temperature and sensed by transducers downstream of the main oil pump. These signals are sent to the Engine Data Manager (EDM). The EDM passes the oil pressure/temperature information to the Signal Conditioning Unit (SCU), which will determine the logic to illuminate an annunciator on the Central Warning System (CWS)

34
Q

How is the PMU powered?

A

The PMU recieves power from the Permanent Magnet Alternator (PMA) which is mounted on the reduction gearbox. The PMA provides 32 VAC, which the PMU converts to DC.

If the PMA fails, PMU recieves power through the 28VDC battery bus.

35
Q

What does it mean to have a free turbine in an engine?

A

The compressor and power turbine are not phyiscally connected.

36
Q

Describe the inertial separator

A

Intake air is passed through the inertial seperator prior to reaching the engine. The inertial seperator causes air molecules to turn 90 degrees to the engine compartment. The heavier particles, such as water or debris, are not able to make the 90 degree turn and are returned to the atomposhere through a bypass duct.

37
Q

What type of ignition system does the T-6A use and what are the benefits?

A

The T-6A usese a dual spark ignition system to initate combustion. This type of ignition system provides quick light ups over a wide range of temperatures.

38
Q

What are the components of the exhaust system

A
  • Exhaust ports
  • Exhaust stacks
39
Q

What is the cause of a ST READY light on the annuciator panel?

A

The PCL is in starting position. Caused by moving the PCL foward from OFF, but below IDLE Position.

40
Q

The rear PCL is directly connected to the FMU (T/F)?

A

False, the front PCL is connected to the FMU. The identitcal movement between the front and rear PCL provide the rear PCL with its ability to control the FMU but it is not a direct connection.

41
Q

How much electricty does the generator provide and what does it power?

A

It generates 28 VDC power. This powers many of the aircraft systems and charges the battery and auxillary battery to 24 VDC.

42
Q

{{41 0 0.png}}

What position would I move the starter switch to if I wanted to start the aircraft?

A

The AUTO/RESET toggle position is used for most engine starts. The switch is spring laoded and automatically reutrns to the NORM positon.

43
Q

Describe the feathered propeller pitch condition and what is an example of when you will use it

A

The blade is aligned nearly straight into the wind, approximately 86 degrees from the perpendicular plane. The blade procues the least amount of drag and no thrust. A flight condition where this is adventagous is during an engine failure in flight

44
Q

What is the purpose of the oil system?

A

The oil system provides a steady flow of filtered oil to vital engine components to ensure their proper lubrication and function. Without the oil system, these components would overhear, seize up and fail.

45
Q

Describe the PCL connection to the Fuel Management Unit (FMU)

A

The PCL is connected to the FMU mechanically by a flexible cable and is also connected electrically.

46
Q

What are the major sections of the engine?

A
  • Accesory Compartment
  • Gas generation section
  • Power turbine section
47
Q

What are the two ways of checking oil levels and what is the preferred method?

A
  • Oil Sight Glass
  • Oil Dipstick (Preferred)
48
Q

What is the purpose of the oil scavenge system?

A

After the pressure pump supplies oil to the engine components, the scavenge oil system returns the oil to the oil tank.

49
Q

What are the contents of the accesory compartment?

A
  • Accesory Gearbox
  • Oil tank
  • Starter/generator
  • Battery
50
Q

Describe the purpose and operation of the reduction gearbox.

A

The reduction gear box is operated by the power turbine. It transfers power from the power turbine to the propeller shaft. It reduces the egnine output from 30,000 RPM to the prop operating speed of 2,000 RPM

51
Q

What are the three elements neccesary for engine operation?

A
  • Air
  • Fuel
  • Heat
52
Q

What happens if the oil filter gets clogged?

A

A filter bypass valve allows unfiltered oil to continue lubricating the engine.

53
Q

What component of the accesory compartment is related to engine operation?

A

The starter

54
Q

If the PMU fails or is off, what sort of engine response should you expect when adjusting the PCL?

A

{{33 1 0.png}}

A step change in the power response, no longer linear

55
Q

You are taxiing back from the runway after flight and this annunciator illumantes, what does it mean?

A

The amber PMU status annunicator after landing means that the PMU has accomandated a fault and requires maintence.

56
Q

Where is 100% torque available from?

A

From sea level to approximately 12,000 to 16,000 feet MSL. Above 16,000 Feet MSL, a decrease in the maximum torque available is noted.

57
Q

What is a reverse flow design for an engine?

A

Air enters the engine at the rear and moves foward during the combustion cycle.

58
Q

What is the unmarked PCL position, when is it used and how do you know you are at the correct position?

A
  • The unmarked PCL position is used during start, it is the starting PCL Positon
  • To find this position, move the PCL away from the OFF position and advance it foward until ST READY light on the annuciator
59
Q

Power for the ignition system is labeled what and found in what cockpit?

A

It is located on a circuit breaker labeled IGN and is located in the front cockpit battery bus circuit breaker panel.

60
Q

How is the generator driven by the engine?

A

Via linkage in the accesory gearbox.

61
Q

Both the front and rear cockpit have a PCL Friction Adjust knob (T/F)?

A

False, one the front PCL. Due to the direct PCL connection, changes in the PCL Fricition Adjust Knob affect the rear PCL

62
Q

What is the engine cowling and what is it’s purpose?

A

The engine cowling is metal panels that cover the enginer compartment. It provides protection for the engine components, decreases drag, and provides an air intake.

63
Q

What is the capacity of the oil system for the T-6A?

A

18.5 US quarts

64
Q

What components of the propulsion system does the oil system lubricate?

A
  • Engine bearings
  • Reduction Gears
  • Accesory Drives
  • Propeller
65
Q

What is the purpose and location of the PIU?

A

The PIU responds to power request from the PMU by regulating oil pressure to the pitch change mechanim. Propeller pitch changes are based upon changes in oil pressure. The PIU can increase the pressure of the oil that is transferred from the PIU through a stationary transfer sleeve into the hollow propeller shaft, changing the blade angle.

66
Q

What is the chip detector system and where is it located?

A

The chip detector system detecs metallic particles in the oil and warns the pilot of possible gear damage. It is located in the reduction gearbox.

67
Q

What does the scavange oil system use to return oil to the oil tank?

A

The system uses several pressure and scavenge pumps

68
Q

How is the propeller pulled into the feathered position?

A

The prop is pulled by the feathering spring and counterweights. Without oil pressure, the propeller should be forced into the feathered position.

69
Q

What must be done to oil to ensure proper lubrication of the engine components?

A

The oil must be pressurized by the pressure pump.

70
Q

What is the PCL cutoff gate?

A

As the PCL is advanced from OFF into the IDLE position, two roller bearing lock in place on the front side of the rocker cam detent to secure the gate to prevent inadvertant engine shutdown.

71
Q

The spark igniters are located where around the engine?

A

4 and 9 o’clock positions

72
Q

Where is the oil cooler located?

A

Lower aft cowl assembly

73
Q

How is oil temperature and pressure measured?

A

By a transducer in the engine oil pressure line downstream of the oil cooler

T-6: Systems 1 (10 decks)

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