MSL / AGL

General

Mean Sea Level / Above Ground Level

Two reference datums for height. Altitude is measured above mean sea level (MSL); height above the terrain directly below is above ground level (AGL).

Also known as

aglabove ground levelmean sea level

See also

QNH Flight Level

Learn ATC the practical way

Practise real radio calls, decode weather and fly ATC scenarios — with an instructor that talks back.