Which combination of factors produces the greatest wake turbulence?

The factor combination that produces the greatest wake turbulence is characterized by being heavy, dirty, and fast. This is because wake turbulence is primarily generated by an aircraft's weight and configuration at the time of flight.

Heavy aircraft produce more pronounced vortices due to their greater mass, leading to more significant disruptions in the air as they pass through it. The term "dirty" refers to the aircraft being in a configuration that generates more lift, such as with landing gear and flaps deployed. These aerodynamic configurations can further enhance the strength of the vortices. Additionally, a higher speed increases the energy released into the wake, generating stronger turbulence.

In contrast, lighter aircraft tend to generate less wake turbulence, while a clean configuration (with landing gear and flaps retracted) produces less lift-induced drag and therefore weaker vortices. Fast flight can amplify wake turbulence, but it is the combination of being heavy and in a dirty configuration that culminates in the greatest intensity of wake turbulence.