What is utilized by ground support crew to signal aircraft during landing?

The correct choice is visual signals. These signals are typically employed by ground support personnel to guide pilots during landing and taxiing. Ground crew use various gestures, flags, and light signals that provide clear and immediate directions to aircraft. This visual communication is crucial because it allows for quick recognition and action, especially in situations where radio communication may be limited or compromised.

Ground radar systems primarily serve to track aircraft movements and manage air traffic rather than provide direct signals to pilots during landing. While communication radios are essential for ongoing dialogue between the aircraft and ground control, ground personnel rely on visual signals for immediate, on-the-spot traffic direction and assistance. Signal enlisted personnel may be involved in managing the communication or assisting, but they do not directly signal the aircraft. Visual signals are standard practice at airports and are universally understood by pilots, making them the most effective method for ground crews during landing operations.