Powerplant

Question 1

What are the engines used in the MC-12?

Answer 1

The PT6A-60A

Question 2

Describe the PT6A-60A

Answer 2

1050 SHP, Free Turbine, Reverse Flow engines.

The power turbines are connected through planetary reduction gearing to a flanged propeller shaft.

Question 3

Power plants may be divided into _______ major sections.

What are they?

Answer 3

Power plants may be divided into three major sections:

Compressor Section
Combustion Section
Power Section

Question 4

The engines are each rated at ____ horsepower.

Answer 4

1050 SHP

The engines are each rated at 1050 horsepower.

Question 5

If you are unable to develop power but ITT and N1 continue to increase, what is likely the problem?

Answer 5

Bleed Valve is not closing

Question 6

What components are located on the Accessory Gear Box?

Answer 6

F – R – O – S – T

Fuel Pumps / Fuel Control 
Refrigerant (right engine only) 
Oil Pumps / Scavenge
Starter Generators  
Tachometer (N1)

Question 7

What are the four stages of compression on the PT6A-60 engine?

Answer 7

Three axial and one centrifugal

Question 8

What is the device that compensates for excess air flow at low N1 settings by bleeding axial compressed air to reduce back pressure in the engine compressor section?

Answer 8

Compressor Bleed Valve

Question 9

What is 25% of compressed air is used for?

Answer 9

Combustion

75% Cooling

Question 10

How many igniter plugs are used to light the fuel/air mixture when the engine is started?

Answer 10

Two. However, only one is required.

Question 11

What are the components of the reduction gear box?

Answer 11

T – Tachometer (N2)
O – Overspeed Governor
P – Primary Governor

The Reduction Gearbox has a two-stage gear box reducing the RPM from 30,000rpm to 1700rpm

Question 12

Where is the chip detector is located?

Answer 12

Bottom of Reduction

Question 13

The oil system is responsible for what?

Answer 13

Lubricating
Cooling
Heating
Adjusting Prop Pitch

Question 14

What action should be taken inflight with oil pressure reading 80psi?

Answer 14

Limit torque to 62% with oil pressure between 60-90psi.

Question 15

If oil pressure drops to 57psi what are the indications on the MFD and what action should be taken?

Answer 15

EIS oil display will be displayed in red (<60) and consider performing ENGINE SHUTDOWN IN FLIGHT.

Question 16

What does Illumination of the green L or R ENG ANTI-ICE annunciator indicate?

Answer 16

The system functioning normally

Question 17

If a bleed air valve fails to ______ as static take-off power is set, torque will indicate _____ than normal and ITT will indicate ______ than normal

Answer 17

close, lower, higher

Question 18

The normal indicated operating oil level is ____ to ____ quarts low.

Answer 18

1-2 (hot) 3 (cold)

Question 19

In the event of an engine fire, how many visual warnings are present on the flightdeck?

Answer 19

Two. L or R ENGINE FIRE and a red FIRE in the ITT/TORQUE gauge.

Question 20

How do we know the F/W valve closed when the switch was depressed?

Answer 20

The green lens in the firewall fuel shutoff valve push button will illuminate.

Question 21

What is the maximum allowable N1?

Answer 21

104%.

Question 22

What is the maximum allowable continuous temperature?

Answer 22

820 deg C.

Question 23

With 120% torque for 56 seconds, has any parameter been exceeded?

Answer 23

Yes, any value between 102-156% is time limited to 20 seconds.

Question 24

The minimum oil temperature allowed for engine start is _____?

Answer 24

(-)40 degrees C

Question 25

The recommended oil temperature for fuel heating is _____?

Answer 25

55 degrees C

Question 26

Oil temperature between 99c and 110c is limited to ____ minutes?

Answer 26

10 minutes

Question 27

What action should be taken inflight with oil pressure reading 80psi?

Answer 27

Limit torque to 62% with oil pressure between 60-90psi.

Question 28

If oil pressure drops to 57psi what are the indications on the MFD and what action should be taken?

Answer 28

EIS oil display will be displayed in yellow (<60) and perform ENGINE SHUTDOWN IN FLIGHT.

Question 29

How many SHP is the PT6A-60A free-turbine turbo prop engine?

Answer 29

1050 shaft horsepower @ 1700 rpm.

Question 30

What is required for the ignitors to activate?

Answer 30

Auto Ignition, when armed, will activate both igniters whenever torque drops below 17% in order to prevent engine loss due to combustion failure. Auto Ignition is checked during Engine Run Up. Auto Ignition is armed during the Line Up Check and remains on until After Landing Check. If motoring the starter is required, the switches can be moved (downward) to the Starter Only position.

Question 31

Q: What is the indication that the Bleed Valve has stuck in the open position?

Answer 31

Low torque with High ITT and N1.

Question 32

Is the Primary Governor part of the Accessory Gear Box?

Answer 32

No.

Question 33

How many fuel nozzles are in the PT6A-60A engine?

Answer 33

14 - There are primary and secondary fuel nozzles that are energized during the start sequence generally around 35% N1

Question 34

Q: Where is the chip detector is located?

a. Top of Accessory Gearbox
b. Bottom of Reduction Gearbox
c. Stage 3
d. Next to burner can (Stage 5)

Answer 34

b: bottom of Reduction Gearbox.