AME - Aircraft Maintenance Engineer Gas Turbine Engine Theory Questions and Answers

Question 1

Which of the following describes the primary function of the turbine section in a gas turbine engine?

Accepted Answer

To drive the compressor and accessories by extracting energy from the hot gas stream.

Answer

The turbine section's main purpose is to extract kinetic and thermal energy from the high-velocity hot gases exiting the combustion chamber. This extracted energy is converted into mechanical power to rotate the main shaft, which in turn drives the compressor section and engine-driven accessories.

Question 2

A turbofan engine is operating at a constant high-altitude cruise. If the density of the air entering the engine decreases, what is the most likely effect on engine performance, assuming RPM remains constant?

Accepted Answer

Thrust will decrease due to reduced mass airflow.

Answer

Thrust is a product of mass airflow and the change in velocity. At a constant RPM, the compressor moves a constant volume of air. If the air density decreases, the mass of that air (mass airflow) also decreases. This reduction in mass airflow directly leads to a decrease in the thrust produced by the engine.

Question 3

In the context of the Brayton cycle as it applies to a gas turbine engine, what process occurs within the combustion chamber?

Accepted Answer

Constant-pressure heat addition

Answer

The Brayton cycle is the thermodynamic model for gas turbine engines. The process within the combustor, where fuel is burned to heat the compressed air, is modeled as a constant-pressure (isobaric) heat addition process.

Question 4

An aircraft's turboprop engine utilizes its gas turbine core primarily to do what?

Accepted Answer

Drive a propeller through a reduction gearbox.

Answer

In a turboprop engine, the vast majority of the energy produced by the gas turbine section is used to drive a propeller via a reduction gearbox. The propeller then accelerates a large mass of air, generating most of the engine's thrust. A small amount of thrust is produced by the exhaust gases.

Question 5

During engine operation, the airflow passages in the compressor section are designed to be divergent in shape between stages. What is the primary purpose of this design?

Accepted Answer

To convert the kinetic energy (velocity) of the airflow into potential energy (pressure).

Answer

In a compressor, the stator vanes form divergent passages after the rotating blades. These passages are designed to slow down the airflow, converting its kinetic energy (velocity) into a rise in static pressure. This process increases the pressure of the air layer by layer through the compressor stages.

AME - Aircraft Maintenance Engineer Practice Test

AME - Aircraft Maintenance Engineer Practice Test

AME - Aircraft Maintenance Engineer Gas Turbine Engine Theory Questions and Answers