Effective February 20, 2025 - April 17, 2025

Enroute High Altitude charts (HI) depict aeronautical navigation information, airways system, special use airspace, communication stations critical for flight in the high level structure. Vertical coverage is from 18,000′ asl and above. 6 charts (3 sheets back-to-back).  Set of ( H 1/2, H 3/4 and H 5/6).