Originally Posted by
gfunkdave
To finish the explanation, FL 50 means 50,000 feet.
Actualy, FL50 is 5,000' (in a standard atmosphere). Add two zeroes. It is not used in the CONUS but is in other parts of the world. Aruba, for example, has a transition altitude of 2,500' and a transition level of FL40.
50,000' would be FL500, in a standard atmosphere.