FAA IFR Terminal Procedures Bound South Central (SC) Vol 2 of 5 (Always Current Edition)

aviators use all kinds of acronyms to describe how high in the air they are you might have heard msl agl qfe flight level probably some others too what exactly do all those mean we'll answer that question in this video on altitudes the faa defines a few measurements of altitude for us the first one we'll look at is true altitude which is the vertical distance of the aircraft above sea level this is shown as feet above mean sea level or msl so 15 000 msl is 15 000 feet above sea level true altitude is also the elevation shown on aeronautical charts for things like terrain obstacles and airports true altitude is useful for planning purposes but there are often situations where a pilot might want to know how high they are above the ground instead of the sea this is called absolute altitude and it's expressed as feet above ground level or agl so why would you need to know your altitude and