If the terrain elevation is 1,295 feet MSL, what is the height above ground level of the base of the ceiling?

• A. 505 feet AGL
• B. 1,295 feet AGL
• C. 1,800 feet AGL
• D. 2,000 feet AGL

Answer: (A)

Height above ground level is found by subtracting the terrain elevation from the ceiling’s base altitude, both in the same reference. If the ceiling base is at 1,800 ft MSL and the terrain is 1,295 ft MSL, then 1,800 minus 1,295 equals 505 ft. So the base of the ceiling is 505 ft above ground level (505 ft AGL). This matches the given data, since converting the ceiling from MSL to AGL requires subtracting the ground elevation from the cloud-base altitude.