Gas Turbines - Auxiliary Power Units and Engine Starting: DGCA Technical General questions

Question 1

In a twin spool engine the typical idle speeds are:

Accepted Answer

60% N2 / 25% N1

Answer

25% N2 / 60% N1

Answer

40% N2 / 30% N1

Answer

80% N2 / 45% N1

Question 2

In a twin spool engine self-sustaining speed is normally reached at:

Accepted Answer

30% N2

Answer

60% N2

Answer

60% N1

Answer

30% N1

Question 3

A typical APU can provide:

Accepted Answer

all of the above

Answer

air for air conditioning on the ground

Answer

air for engine starting

Answer

electrical power for ground or in-flight use

Question 4

The air supply for an air start system is:

Accepted Answer

at a relatively low pressure, but high volume

Answer

filtered to prevent damage to the starter motor

Answer

preheated to avoid icing in the starter nozzle guide vanes

Answer

at a high pressure but low volume

Question 5

Which of the following would result in an automatic shutdown of an APU? 1. Overspeed of compressor 2. Over-temp of lubrication system 3. Turbine over-temp 4. Combustion chamber over-temp 5. Compressor outlet pressure exceeded 6. Low pressure of lubrication system

Accepted Answer

1, 2, 3 and 6

Answer

1, 2, 4 and 6

Answer

2, 3, 5 and 6

Answer

2, 3, 4 and 6

Gas Turbines - Auxiliary Power Units and Engine Starting: DGCA Technical General questions

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