The Air Assault School Phase I homework. Flashcard maker: Christine Brunetti. What is one physical feature used to distinguish between the AH-64A and AH-64D? Fire Control Radar (FCR) Cheese Wheel. What is the cleared diameter of a size 1 landing point? 25 Meters. What are the dimensions for additional touchdown point lights at night for utility aircraft? 5 Meters. When working with obstacles.