KA350 Poweplant

Question 1

State the Shaft Horsepower of the PT6A-60A

Answer 1

1050 SHP

Question 2

Name the Types and number of stages in the compressor section of the PT6A-60A

Answer 2

3 Axial and 1 Centrifugal Compressor

Question 3

What is the purpose of the compressor bleed valve and under what condition is it open?

Answer 3

Diverts excess P2.5 air at low power settings to prevent compressor stall.
Open below 90% N1

Question 4

What would the indications of a low pressure boost pump failure be? If the condition continued what restriction applies to the engine operation?

Answer 4

[FUEL PRESS LO] annunciator

10 Hrs max operation until overhaul

Question 5

During the start cycle you notice an initial fuel flow of 200pph. What item has most probably failed and what actions should take place?

Answer 5

Higher than normal fuel flow (normal 100pph). Indicates the flow divider has failed.
Stop the start sequence.

Question 6

How many fuel nozzels are in each engine?

Answer 6

14

7 primary and 7 secondary

Question 7

With the AUTO IGNITION switch in the ARM position, the igniters operate:
A. Continuously
B. As controlled by the stall warning system
C. Only when the Torque reduces below 17%
D. Continuously if TOrque is greater than 10%

Answer 7

C. Only when the Torque reduces below 17%

Question 8

Complete the starter cycle limitations

Answer 8

30 Secs ON - 5 Mins OFF
30 Secs ON - 5 Mins OFF
30 Secs ON - 30 Mins OFF

Question 9

Which of the following is most likely to require an airborne engine shutdown?
A. An oil pressure of 50 PSI
B. Chip light illumination with no other indications
C. NP between 1700 and 1750RPM

Answer 9

A. An oil pressure of 50 PSI

Question 10

Is the fuel heated and if so, how, prior to entering the Fuel Control Unit (FCU)?

Answer 10

YES, via the oil-to-fuel heat exchanger

Question 11

List four items that are driven by the accessory gearbox

Answer 11

Fuel Control Unit (and High Pressure Fuel Pump)
Oil lubricating and scavange pumps
N1 Tachogenerator
DC Starter / Generator
Air Conditioning Compressor (RH Engine only)
Low pressure fuel pump

Question 12

Is the engine fitted with a purge system? Briefly describe it

Answer 12

Yes, an EPA cannister stores P3 air an on engine shutdown the EPA cannister senses a drop in pressure and dumps its pressurised air through the combustuion chamber to purge fuel as a vapor through the exhaust

Question 13

Describe the two primary purposes of the PROP levers.

Answer 13

Adjust PROP RPM

Enable feather selection

Question 14

Under what conditions will the AUTO FEATHER system feather the prop?

Answer 14

AUTO FEATHER switch ARMED
PWR levers 88-90% N1
Torque below 10% (at 17% opposite engine auto feather is disabled to prevent double engine auto feather)

Question 15

During flight you notice that the prop RPM is ~1768 despite the prop lever being set at a low RPM. WHat component is controlling the prop RPM and what limits now apply?

Answer 15

The Hydraulice overpseed governor is controlling the prop RPM due to a failure of the primary governor.

104% Prop RPM or 1768 is now the Prop limit and Torque limit now 96% Max

Question 16

Under what conditions must the AUTO IGNITION be armed?

Answer 16

Precipitation, Icing or Turbulence

Question 17

What pilot control will cause BETA Valve movement

Answer 17

Prop Lever - requires an underspeed condition for it to be active

Question 18

WHich aircraft component then causes the BETA valve to move to equillibrium?

Answer 18

The reversing rod and feedback ring

Question 19

Why should reverse not be selected without the engines operating?

Answer 19

Potential damage to the reversing rod could occur.

Question 20

One of the functions of the Fuel Topping Governor is to:
A. Provide back up control of the oil pressure prop dome to prevent prop overspeed in reverse
B. Prevent prop overspeed in the event of a CSU and overspeed governor failure
C. Set the maximum power output of the engine by regulating P3
D. Limit fuel to the Gas producer section to prevent an over temp of the engine.

Answer 20

B. Prevent prop overspeed in the event of a CSU or overspeed governor failure

Question 21

When will the Fuel Topping Governor effect prop RPM? How is this done?

Answer 21

At 106% Prop RPM, will bleed of P3 air to the FCU to reduce N1

Question 22

What conditions are met to illuminate the [RVS NOT RDY] annunciator?

Answer 22

Props not FULL INCREASE and landing gear is down.

Question 23

Torque sensing is required for operation of the propeller:
A. Synchro system
B. Auot-Feather system
C. Low-Pitch stop
D. BETA Range

Answer 23

B. Auto-Feather system

Question 24

During flight at high altitude an unexpected rise in oil temp is noted on one engine only. Wjat is the most likely cause?

Answer 24

Failure of the oil cooler thermostat causing oil to bypass the oil cooler.

Question 25

What two conditions must be met to activate the Ground Idle Solenoid on landing?

Answer 25

Right squat switch engaged

Both power levers lifted and moved aft of the detent.