FAA Powerplant Written Practice Test

What is the primary function of the compressor on a gas turbine engine?

1. Increase the temperature of the air

2. Supply air in sufficient quantity for combustion

3. Reduce the volume of exhaust gases

4. Cool the engine components

The correct answer is: Supply air in sufficient quantity for combustion

The primary function of the compressor in a gas turbine engine is to supply air in sufficient quantity for combustion. This key role involves drawing in ambient air and compressing it to a higher pressure before it enters the combustion chamber. The compression process increases the density of the air, which allows for a more efficient combustion process by providing a larger quantity of air for mixing with the fuel. This enrichment of air not only improves the efficiency of fuel combustion but also enhances overall engine performance by ensuring that there is enough oxygen available for the combustion of fuel. Without proper air supply, the engine would not generate the necessary thrust or power, making the compressor's function crucial to the operation of the gas turbine. The other functions depicted in the choices, such as increasing air temperature or cooling engine components, are secondary effects or are addressed by other parts of the engine. For instance, while the compression increases air pressure, it can also slightly raise thermometer, that is not its primary role. Likewise, the management of exhaust gases and engine cooling is achieved through different components like the turbine section and cooling systems, respectively.