Which element is NOT part of the afterburner assembly?

The compressor fan is not part of the afterburner assembly. In a gas turbine engine, the afterburner is a component designed to augment thrust by mixing additional fuel with exhaust gases after they have passed through the engine's turbine section.

The afterburner assembly typically includes elements like flame holders, which stabilize the combustion process by ensuring that the fuel mixes thoroughly with the hot exhaust gases, and the afterburner duct, which channels these gases while allowing the combustion to take place. The variable area exhaust nozzle plays a critical role in controlling the flow of exhaust gases, enhancing performance, and adjusting the thrust depending on the engine's operational phase.

In contrast, the compressor fan, which is part of the engine's compressor section, operates upstream of the combustion and turbine sections, compressing incoming air before it enters the combustion chamber. Thus, it is not directly involved in the afterburner functionality, making it the correct answer to the question.