groundprox
groundprox
(ˈɡraʊndˌprɒks)n
(Aeronautics) aeronautics a device that alerts a pilot of a passenger aircraft when the altitude falls below a certain level
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014