Which two distances are essential for takeoff and landing performance calculations?

The correct choice highlights two critical distances for evaluating a pilot’s ability to safely take off and land an aircraft: the ground roll distance and the total distance needed to clear an obstacle.

Ground roll distance refers to the length of runway required for an aircraft to accelerate from a standstill to the point at which it becomes airborne. This distance is vital, as pilots must ensure that the available runway length is sufficient for their aircraft to achieve takeoff speed.

The total distance to clear an obstacle encompasses the entire vertical and horizontal distance required for an aircraft to reach a specific altitude and ensure it can safely pass over an obstacle, such as trees or buildings, in the vicinity of the runway. This calculation is particularly important for operations in environments where natural or man-made obstructions are present near the airport.

Together, these two distances contribute to a pilot’s understanding of the performance characteristics of their aircraft in relation to the conditions of the airport and the surrounding terrain, enabling informed decision-making regarding takeoffs and landings.

The other choices, while they pertain to flight performance, do not directly relate to the essential calculations necessary for safely executing takeoffs and landings. For example, climb rate and stall speed are crucial for understanding the aircraft's performance during flight,