+ double groundlevel_m = get_groundlevel_m(lat, lon, alt);
+ _set_Runway_altitude(groundlevel_m*SG_METER_TO_FEET);
+ _set_Altitude_AGL((alt-groundlevel_m)*SG_METER_TO_FEET);
+
+ // the smallest agl of all gears
+ fgSetFloat("/position/gear-agl-m", model->getAGL());
+ fgSetFloat("/position/gear-agl-ft", model->getAGL()*M2FT);