When must the approach clearance for Vicksburg be issued?

The correct timing for issuing an approach clearance, particularly in this context, is essential for ensuring safe and efficient air traffic operations. The approach clearance for Vicksburg must be issued before the center estimate is provided to maintain proper sequencing and ensure that the aircraft is cleared for the approach in a timely manner.

Issuing the clearance before the DORTS center estimate helps in managing the flow of traffic and allows for better coordination between different air traffic controllers. This practice provides the pilot with the necessary information to prepare for the approach and landing, avoiding potential delays or miscommunications.

In contrast, issuing the clearance before the pilot requests it could lead to confusion if the pilot is not ready for the approach, while issuing it at the latest possible time before landing may not allow sufficient time for the pilot to prepare. Additionally, issuing the clearance after the holding pattern is established could create unnecessary holding delays, which is not ideal for efficient air traffic management. Thus, the timing of issuing the clearance is critical in ensuring a smooth and safe transition into the airport environment.