Approach and Departure Zone : A clear zone available for flight of a helicopter as it approaches or departs from the heliport's designated takeoff and landing area. (RP 2L)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}