Ground Cushion Area : Ground cushion area is the solid portion of a heliport surface provided for proper ground cushion effect. This area may be only the flight deck or the flight deck plus its perimeter safety shelf. (RP 2L)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}