What is one disadvantage of procedural control (PD) in air traffic management?

The correct choice highlights that procedural control in air traffic management comes with the challenge of needing to protect more altitudes. In procedural control environments, aircraft are often separated by altitude and horizontal distance based on predetermined procedures rather than real-time tactical adjustments. This necessitates maintaining a buffer around altitude assignments to ensure safe separation between aircraft, which can be complicated in busy airspace.

This can lead to inefficiencies such as increased workload for the controller, as they must constantly monitor multiple altitude assignments and ensure compliance with separation standards. The requirement to protect a greater number of altitudes can limit the flexibility that controllers have in managing the air traffic flow effectively, particularly in dynamic or congested environments.

In contrast, procedural control's focus on structured procedures may simplify some aspects of traffic sequencing, requiring less real-time coordination between sectors and allowing controllers to maintain attention on altitude assignments. However, the advantage of clarity and predictability comes with the trade-off of protecting more airspace, increasing complexity and workload for air traffic controllers.