#include <Main/util.hxx>
#include <Environment/gravity.hxx>
+#include <Main/fg_props.hxx>
using namespace simgear;
using std::string;
_elevation(0.0),
_rotation(0.0),
hs(0),
+_elapsed_time(0),
_az_random_error(0.0),
_el_random_error(0.0),
-_elapsed_time(0),
_aero_stabilised(false),
_drag_area(0.007),
_cd(0.029),