Mean Sea Level (MSL) 7 : The height of the surface of the sea for all stages of the tide, used as a reference for elevations. Also called sea level datum
United States Department of Transportation, Federal Aviation Administration, Final Environmental Impact Statement: New York/New Jersey/Philadelphia Metropolitan Area Airspace Redesign, Chapter Seven: List of Acronyms, Abbreviations and Glossary of Terms In This EIS, Volume One: Documentation, Washington, DC, USA 2007. http://www.dirtyairport.com/dotnetnuke/LinkClick.a spx?fileticket=bnCberFBJnk%3D&tabid=56&mid=372, (Avn Sfty - Amer) {1015}