Which cue indicates the time to report Initial for RWY 13L/13R?

The cue indicating the time to report Initial for RWY 13L/13R is when crossing the extended centerline of RWY 18. This is significant because reporting Initial is an essential part of entering the traffic pattern for landing on parallel runways like 13L and 13R. Crossing the extended centerline of another runway, in this case, RWY 18, provides a specific geographic reference that signals the pilot's position relative to the runway they are preparing to land on.

This cue ensures that the pilot is aware of their location and can properly align themselves within the traffic flow of the airport, making sure to maintain safety and coordination with other aircraft. Thus, using the extended centerline of RWY 18 as a reference helps in establishing a standardized reporting procedure that all pilots can follow, enhancing the overall efficiency and safety of airport operations.