Why is it essential to inform approach control about anticipated delays?

Informing approach control about anticipated delays is essential primarily to ensure safe aircraft separation and management. When delays occur, they can disrupt the flow of air traffic, potentially leading to an increased risk of congestion and unsafe scenarios. Approach control is responsible for the sequencing and spacing of aircraft as they prepare to land, so having the most current information allows controllers to make informed decisions regarding the timing of arrivals. This helps them maintain safe distances between aircraft, ensuring that all operational safety standards are met and that the overall efficiency of the airspace is preserved.

While other factors, such as slot booking or regulatory compliance, are important in air traffic management, the primary concern with reporting delays is maintaining safety and operational integrity within the airspace system.