What altitude do aircraft west of J35 landing at KAEX or KESF need to be below when crossing the center boundary?

The correct altitude for aircraft west of J35 landing at KAEX or KESF to be below when crossing the center boundary is 12,000 feet. This altitude is designated to maintain safe separation between aircraft operating in adjacent airspaces, particularly in areas where altitude conflicts could arise due to the proximity of other traffic or air routes.

Maintaining an altitude below 12,000 feet ensures that these aircraft remain within controlled airspace that is appropriate for their landing procedure and helps to prevent any altitude deviations that could lead to safety risks. Coordination with radar controllers is essential to enforce these altitude restrictions effectively, ensuring that all traffic is managed safely and efficiently.

This specific altitude is determined by regulatory guidelines and radar traffic management practices that prioritize safety and operational effectiveness in busy airspace environments. Ultimately, the correct answer of 12,000 feet reflects the standards set forth for safe operation to harmonize traffic patterns as aircraft approach their destination airports.