Brightling - Notso and others. Thought I'd mention that "Manual of Air Traffic Services Part One (ALL ATC'ers Bible)" Is no-ones Bilble unless UR in on a different planet or Island. I'd say whatever ICAO says is the one to go with as they ultimately are the Body to which most of us are contracted. (FAA do there own thing). I believe ICAO says "Hundreds for level's are good ie. FL100 FL200 etc!. .. .Go Springbokkie GO <img border="0" title="" alt="[Big Grin]" src="biggrin.gif" /> <img border="0" title="" alt="[Big Grin]" src="biggrin.gif" />. . . . <small>[ 07 March 2002, 09:01: Message edited by: gofor ]</small>