Final Answer:
SSI/BQK landers must cross the Center boundary at or below 2,500 feet.
Step-by-step explanation:
In aviation, the Center boundary refers to the transition between different airspace control centers. For SSI/BQK landers, the requirement is to cross this boundary at or below an altitude of 2,500 feet. This altitude restriction is likely specified for coordination and safety reasons, ensuring smooth handoffs between different air traffic control centers and maintaining separation between aircraft operating in adjacent airspace.
The altitude restriction of 2,500 feet is crucial for the safe and efficient management of air traffic. It helps prevent conflicts between aircraft and ensures that the handoff procedures between air traffic control centers are conducted in a controlled and organized manner, contributing to overall aviation safety.