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Ground School Systems 1 > PC-21 Propeller System > Flashcards

PC-21 Propeller System Flashcards

1
Q

What propeller is the PC-21 fitted with? What direction does it rotate?

A
  • Composite, five blade, Hartzell constant speed feathering propeller.
  • Clockwise
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2
Q

What is the purpose of the propeller?

A

Convert engine rotation to thrust to propel the aircraft.

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3
Q

What does the engine turn the propeller through?

A

Reduction gearbox and propeller shaft.

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4
Q

What prop speeds produce high efficiency?

A

Close to the speed of sound.

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5
Q

What design feature is included to reduce the propeller noise and improve efficiency?

A

Sweeping the blades back.

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6
Q

What are the advantages of a constant speed (RPM) prop?

A
  1. Allows prop to operate a maximum efficiency

2. Allows the engine RPM to remain within the narrow RPM range ideal for turboprops.

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7
Q

What are some advantages of composite blades?

A
  1. Longer service life

2. Substantial weight reduction

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8
Q

What does increasing the number of blades allow for?

A
  1. Noise reduction
  2. Less vibration
  3. Smaller diameter propeller that is less vulnerable to FOD.
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9
Q

What are the main components and subsystems of the propeller system?

A
  1. Propeller assembly
  2. Propeller control system
  3. Propeller de-ice system
  4. Propeller related cockpit controls.
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10
Q

What are the three propeller sub assembly components?

A
  1. Blades
  2. Spinner
  3. Hub Assembly
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11
Q

What does each blade have?

A
  1. Counterweight that continually attempts to turn the blade back towards the coarse pitch and feathered position, due to props rotational centrifugal force
  2. A titanium erosion strip that protects the leading edge surfaces of the blade from the effects of erosion and provides an earth path in case of a lighting strike
  3. De-Icing strip that prevents build-up of ice on the blades.
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12
Q

What is the spinner and what is it made of?

A
  1. Protects the propeller hub and gives it an aerodynamic shape.
  2. Made from graphite composite material.
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13
Q

What is the hub assembly and what is it made of?

A

Aluminum hub assembly is attached to the prop shaft and holds each propeller in place on a thrust bearing, which allows the blade to change its pitch angle.

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14
Q

What is the main purpose of the propeller control system?

A

To automatically change the propeller blade angle to maintain propeller speed at 100% RPM throughout the various power settings

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15
Q

What are the key components of the prop control system?

A
  • Power Management Unit (PMU)
  • Propeller Interface Unit (PIU)
  • Power Control Lever (PCL)
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16
Q

What are the key components of the propeller de-ice system?

A
  1. De-ice strip, with built-in heater element, on each propeller blade
  2. Prop de-ice controller with two control OAT sensors
  3. Prop push button on de-ice panel.
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17
Q

What prop controls are related to the prop system?

A
  1. PCL

2. PROP push button.

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18
Q

How does the PCL indirectly control the pitch angle of the prop blades?

A

Through interaction with engine PMU and the PIU.

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19
Q

What external systems does the propeller system integrate with?

A
  1. Power plant
  2. Alerting system
  3. Health and Usage Monitoring System
  4. Landing gear WOW and PCL sensors.
20
Q

How is the prop heater elements powered?

A

From GEN 2 BUS

21
Q

Where is the PIU on the engine and how is it controlled?

A
  1. On top of the reduction gearbox

2. Controlled by the PMU

22
Q

What type of component is the PIU?

A

Electro-hydraulic-mechanical component

23
Q

How do the primary governor and the mechanical overspeed governor in the PIU work?

A

Use controlled oil pressure from reduction gearbox to then control the propeller blade angle and consequently, the propeller rotational speed.

24
Q

What does propeller do when PCL is in FUEL OFF position?

A

Electrically commanded to feather to provide least amount of drag in case of an engine shut-down in the air.

25
Q

What occurs during engine start when the PCL is moved to the IDLE position?

A

The propeller is electrically commanded to unfeather and as engine oil pressure increases, the PIU will rotate the propeller blades towards the fine pitch position.

26
Q

What will occur with a loss of oil pressure or engine failure?

A

Blades will automatically feather.

27
Q

Under what conditions does the prop de-ice controller not work?

A
  • OAT > 10 C
  • Engine oil pressure is < 40 psi
  • Prop speed is < 630 RPM
28
Q

Which displays show prop related info?

A
  1. EMD
  2. MFD ENG
  3. DWP
  4. DE-ICE panel
29
Q

When is the prop RPM indication show on the MFD ENG page ?

A

When prop speed increases > 320 RPM.

30
Q

When is the prop speed displayed on the EMD?

A

When it is approaching a limit or is going out of limits.

31
Q

What occurs when Prop de-ice is turned on?

A

Green PROP will display on DWP

Will display ON on the de-ice panel.

32
Q

What should be checked on the propeller during the preflight?

A
  1. Ensure that there is no grease or oil leaking from the spinner or running down the propeller blades
  2. Check the blades for scratches, nicks, cracks or signs of debonding. If any are found ask the groundcrew to determine whether the prop is still airworthy.
  3. Ensure de-ice boots are securely attached to the blades.
  4. Check prop blades for evidence of lightning strikes.
  5. Rotate the propeller and check that is moves easily without grinding or scraping noises.
  6. Ensure that the prop is firmly mounted.
33
Q

Is the PC-21 cleared for flight into know icing conditions?

A

No

34
Q

What should be done if icing conditions arise?

A
  1. Activate de-ice system to prevent ice formation

2. Take action to leave the area immediately.

35
Q

What is the common cause if aircraft power has to be increased to maintain speed or vibrations occurs?

A

Icing

36
Q

What should be done to the prop when flying is complete?

A

Ensure that the prop restraints are replaced to prevent the propeller from continuously wind-milling without oil supply to the reduction gearbox bearings.

37
Q

When surface wind is from behind, what RPM should the prop be limited to?

A

1600 RPM.

38
Q

What actions should be taken in Manual mode to keep prop within limits?

A
  1. Avoid rapid power changes and move the PCL carefully

2. Ensure that the prop remains above 1900 RPM is the NG is > 90%

39
Q

What may occur in the event of a compressor stall or surge with the propeller?

A

The propeller RPM may also surge.

40
Q

When will a red PROP SPEED warning displayed in the alert area on the MFD/ EMD area?

A

When the prop RPM > 2200 RPM.

41
Q

When is the amber PROP SPEED caution displayed?

A
  1. IF prop speed is > 2080 RPM for > 3s.

2. If propeller speed < 1900 RPM for > 3 s while NG > 90%.

42
Q

When will amber ICE PROP caution be displayed in the alert area on the MFD and an amber ICE caption on the DWP?

A
  1. A malfunction is detected in the propeller de-ice system

2. When the propeller de-icing is selected ON, when the OAT > 10 C

43
Q

What warning is shown when metal particles are detected in the propeller reduction gearbox?

A

Amber CHIP PROP caution is shown in the MFD alert area and an amber CHIP caption is shown on the DWP.

44
Q

What will show if the metal particles sense function for the prop reduction gearbox is not available?

A

A grey CHIP PROP ALRT advisory is shown in the MFD alert area.

45
Q

What will occur when the Propeller Interface Unit increases the oil pressure to the propeller assembly?

A

It will make the propeller blade angle smaller (fine pitch)

Ground School Systems 1 (12 decks)

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