Which statement regarding vortex circulation is true?

The statement regarding vortex circulation that is true highlights how vortex circulation generated by helicopters in forward flight behaves similarly to wingtip vortices produced by airplanes. In both cases, as the aircraft moves through the air, it generates a rotating flow of air around its wingtips. For helicopters, this occurs due to the rotor blades creating lift, leading to a persistent and trailing vortex that can affect other aircraft flying behind them.

This principle is critical for aviation safety. The vortices can remain significant even at some distance behind the helicopter, posing a hazard to other aircraft during takeoff and landing phases. Understanding this concept is fundamental for pilots, as it informs them about the potential turbulence and wake hazards they may encounter during flight near helicopters.