24

Question 1

The advantages of an axial flow compressor compared to a centrifugal flow compressor of the same frontal area in a gas turbine engine are:

Answer 1

Higher pressure ratios and greater mass airflow

Question 2

Regarding the measurement of temperature in a gas turbine engine:

Answer 2

JPT measures jet pipe gas temperature

Question 3

The function of a negative torque system (NTS) in a turboprop is to:

Answer 3

Increase the propeller blade angle to prevent the turbine from being driven by the propeller

Question 4

The N1 gauge indicate in a turbofan engine indicates:

Answer 4

Fan RPM

Question 5

With reference to a gas turbine engine:

Answer 5

TGT is the temperature of the gas between the turbine stages

Question 6

The fuel flow transmitter in the fuel system of a large jet transport category aircraft is located:

Answer 6

At the outlet from the fuel control unit

Question 7

The pressure rise in the centrifugal compressor of a gas turbine engine occurs in:

Answer 7

Both the impeller and the diffuser

Question 8

On a wet day take-off in a jet engine aircraft, the igniter plugs may be selected to continuous ignition. In this case the characteristics of the spark will be:

Answer 8

Low value (joules) at high voltage to preserve the igniter plugs and the ignition unit

Question 9

The design feature which is not an advantage of the annular combustion chamber design in a modern gas turbine engine, compared to other multi-chamber designs is:

Answer 9

Greater structural integrity

Question 10

A particular turbine fuel has a specific gravity of 0.80 at a given temperature. A temperature rise of 20oC will result in a calorific (energy) value for the fuel which is:

Answer 10

The same energy value as for the original temperature per kg of fuel

Question 11

The function of the torque meter in a turboprop powered aircraft is to:

Answer 11

Monitor shaft output power

Question 12

Regarding the measurement of temperature in a gas turbine engine:

Answer 12

JPT measures jet pipe gas temperature

Question 13

The ram air effect on a turbojet engine results in a conversion of:

Answer 13

The kinetic energy in the airstream into pressure

Question 14

The effect of a change in temperature on the specific gravity of AVTUR is:

Answer 14

Specific gravity decreases as temperature increases

Question 15

The purpose of the air shroud on an atomiser type (duplex) fuel spray nozzle in the combustion chamber of a gas turbine engine is:

Answer 15

To reduce carbon deposits around the nozzle tip and cool the nozzle

Question 16

The function of variable inlet guide vanes in a gas turbine engine is:

Answer 16

To prevent compressor blade stall when the engine is operating at low RPM

Question 17

The changes in the gas flow within the combustion chamber of a gas turbine engine are:

Answer 17

Volume increases, temperature increases, pressure decreases or remains constant

Question 18

Modern jet engine design RPM is:

Answer 18

Slightly less than maximum RPM