Which calculation is NOT influenced by the presence of a clearway?

The calculation that is not influenced by the presence of a clearway is the landing distance available.

When considering take-off and related calculations, a clearway is an area beyond the take-off runway that is free of obstructions and can be used to increase the operational performance of the aircraft during the take-off phase. The clearway can reduce the required take-off distance and allow for increased take-off weights by providing additional space for the aircraft to accelerate and, in case of an engine failure, to reach a safe speed before the end of the runway.

Conversely, the landing distance available calculates how much runway space is available for the aircraft to land and come to a stop. This distance is determined primarily by the length of the runway and any relevant obstacles at the departure end but does not factor in the clearway because it is concerned with the landing phase, which is a different operational context from take-off calculations.

Thus, the presence of a clearway has no bearing on landing distance considerations but is quite essential for various take-off performance metrics.