Airmail PIlot Jack Knight Crashes 1921 in Blizzard.

Just over 200 miles west of North Platte the front range of Rockies stand like a wall over which the DH-4s faced their first real altitude challenge. Cheyenne, WY (CYS) sits at over 6,600 feet, twice as high as North Platte. Just to the west stands Medicine Bow Peak rising over 12,000 feet. Rated at a maximum operational altitude of 21,000 feet, the DH-4 Liberty engine could struggle to maintain 10,000 feet. Fortunately, pilots could fly around the north side of the peak where the terrain, most under 10,000 was navigable in the DH-4, though Jack Knight had crashed in this wilderness just weeks before the famous night flight to Chicago.