For an ALTRV, what is a prerequisite for ATC clearance despite the airspace approval?

The prerequisite for ATC clearance for an ALTRV (Alternate Temporary Refuge Vertical Route) despite having airspace approval is the requirement that separation standards must be met. This is crucial because air traffic control is responsible for maintaining safe distances between aircraft to prevent collisions. Even if an aircraft has been approved to use ALTRV airspace, it cannot proceed until the controller is confident that separation from other traffic can be maintained. This ensures the safety of all aircraft in the vicinity.

Meeting separation standards involves confirming that the aircraft can be safely guided within the airspace without conflicting with other operations. This consideration remains paramount regardless of any prior airspace approvals that may have been granted. Therefore, ensuring that separation standards are met is a vital step that underpins the overall safety and effectiveness of air traffic management.