Final answer:
The term for low-visibility conditions with an RVR between 600 ft and 1200 ft is Low-Visibility Operations, which necessitate stringent safety procedures on the airfield.
Step-by-step explanation:
The term for low-visibility conditions where the runway visual range (RVR) is between 600 ft (183 m) and 1200 ft (366 m), leading to extra restrictions for airside vehicle operators, is d) Low-Visibility Operations. These operations involve specific procedures to ensure safety on the airfield when visibility is reduced. Air traffic controllers, pilots, and vehicle operators must follow stringent guidelines to coordinate movements and maintain safe distances.
In reference to the presented task (Figure 2.34, items 61a and 61b), the calculation of the position vectors and the distance between two aircraft in terms of their altitudes and angles of ascent involves principles of vector analysis and trigonometry. This situational awareness is crucial for preventing collisions and managing traffic efficiently, especially during low-visibility operations.