diff --git a/src/Airports/GenAirports850/object.cxx b/src/Airports/GenAirports850/object.cxx
index 4715dabc..a89085ac 100644
--- a/src/Airports/GenAirports850/object.cxx
+++ b/src/Airports/GenAirports850/object.cxx
@@ -1,4 +1,4 @@
-#include <simgear/math/sg_geodesy.hxx>
+#include <simgear/math/SGMathFwd.hxx>
 #include <simgear/debug/logstream.hxx>
 #include "object.hxx"
 
@@ -17,25 +17,18 @@ void LightingObj::BuildBtg( superpoly_list* lights )
     double left_hdg = heading - 90.0;
     if ( left_hdg < 0 ) { left_hdg += 360.0; }
 
-    Point3D ref(lon, lat, 0.0);
+    SGGeod ref = SGGeod::fromDeg(lon, lat);
 
-    // Calculate the normal direction once for all objects.
+    // Calculate the light normal with the help of a second point
+    // in the object heading direction.
     // SimGear takes care of the glideslope angle calculation from the normal
+    SGVec3d cart1 = SGVec3d::fromGeod(SGGeodesy::direct( ref, heading, 10));
+    SGVec3d cart2 = SGVec3d::fromGeod(ref);
 
-    // calculate a second point in the object heading direction
-    double lon2 = 0, lat2 = 0, r;
-    geo_direct_wgs_84 ( lat, lon, heading,
-                        10, &lat2, &lon2, &r);
-
-    Point3D cart1 = sgGeodToCart( Point3D(lon2, lat2, 0.0) * SG_DEGREES_TO_RADIANS );
-    Point3D cart2 = sgGeodToCart( ref * SG_DEGREES_TO_RADIANS );
-
-    Point3D normal = cart2 - cart1;
-    double length = normal.distance3D( Point3D(0.0) );
-    normal = normal / length;
+    Point3D normal = Point3D::fromSGVec3(normalize(cart2 - cart1));
 
     // We know our normal, now create the lights
-    Point3D pt1;
+    SGGeod pt1;
 
     if (type == 1)
     {
@@ -45,46 +38,34 @@ void LightingObj::BuildBtg( superpoly_list* lights )
         // Space between the bars is 200m
 
         // Go to downwind bar
-        geo_direct_wgs_84 ( ref.lat(), ref.lon(), heading,
-                            -100, &lat2, &lon2, &r );
-        pt1 = Point3D( lon2, lat2, 0.0 );
+        pt1 = SGGeodesy::direct( ref, heading, -100 );
 
         // unit1
-        geo_direct_wgs_84 ( pt1.lat(), pt1.lon(), left_hdg,
-                            -5, &lat2, &lon2, &r );
-        pt1 = Point3D( lon2, lat2, 0.0 );
-        lightobj.push_back( pt1 );
+        pt1 = SGGeodesy::direct( pt1, left_hdg, -5 );
+        lightobj.push_back( Point3D::fromSGGeod(pt1) );
         normals.push_back( normal );
 
         // unit2+3
         for (int i = 0; i < 2; ++i)
         {
-            geo_direct_wgs_84 ( pt1.lat(), pt1.lon(), left_hdg,
-                                5, &lat2, &lon2, &r );
-            pt1 = Point3D( lon2, lat2, 0.0 );
-            lightobj.push_back( pt1 );
+            pt1 = SGGeodesy::direct( pt1, left_hdg, 5 );
+            lightobj.push_back( Point3D::fromSGGeod(pt1) );
             normals.push_back( normal );
         }
 
         // Go to upwind bar
-        geo_direct_wgs_84 ( ref.lat(), ref.lon(), heading,
-                            100, &lat2, &lon2, &r );
-        pt1 = Point3D( lon2, lat2, 0.0 );
+        pt1 = SGGeodesy::direct( ref, heading, 100 );
 
         // unit4
-        geo_direct_wgs_84 ( pt1.lat(), pt1.lon(), left_hdg,
-                            -5, &lat2, &lon2, &r );
-        pt1 = Point3D( lon2, lat2, 0.0 );
-        lightobj.push_back( pt1 );
+        pt1 = SGGeodesy::direct( pt1, left_hdg, -5 );
+        lightobj.push_back( Point3D::fromSGGeod(pt1) );
         normals.push_back( normal );
 
         // unit5+6
         for (int i = 0; i < 2; ++i)
         {
-            geo_direct_wgs_84 ( pt1.lat(), pt1.lon(), left_hdg,
-                                5, &lat2, &lon2, &r );
-            pt1 = Point3D( lon2, lat2, 0.0 );
-            lightobj.push_back( pt1 );
+            pt1 = SGGeodesy::direct( pt1, left_hdg,5 );
+            lightobj.push_back( Point3D::fromSGGeod(pt1) );
             normals.push_back( normal );
         }
     }
@@ -93,19 +74,15 @@ void LightingObj::BuildBtg( superpoly_list* lights )
         SG_LOG(SG_GENERAL, SG_DEBUG, "Generating PAPI 4L = " << assoc_rw);
 
         // unit1
-        geo_direct_wgs_84 ( ref.lat(), ref.lon(), left_hdg,
-                            -12, &lat2, &lon2, &r );
-        pt1 = Point3D( lon2, lat2, 0.0 );
-        lightobj.push_back( pt1 );
+        pt1 = SGGeodesy::direct( ref, left_hdg, -12 );
+        lightobj.push_back( Point3D::fromSGGeod(pt1) );
         normals.push_back( normal );
 
         // unit2-4
         for (int i = 0; i < 3; ++i)
         {
-            geo_direct_wgs_84 ( pt1.lat(), pt1.lon(), left_hdg,
-                                8, &lat2, &lon2, &r );
-            pt1 = Point3D( lon2, lat2, 0.0 );
-            lightobj.push_back( pt1 );
+            pt1 = SGGeodesy::direct( pt1, left_hdg, 8 );
+            lightobj.push_back( Point3D::fromSGGeod(pt1) );
             normals.push_back( normal );
         }
     }
@@ -114,19 +91,15 @@ void LightingObj::BuildBtg( superpoly_list* lights )
         SG_LOG(SG_GENERAL, SG_DEBUG, "Generating PAPI 4R = " << assoc_rw);
 
         // unit1
-        geo_direct_wgs_84 ( ref.lat(), ref.lon(), left_hdg,
-                            12, &lat2, &lon2, &r );
-        pt1 = Point3D( lon2, lat2, 0.0 );
-        lightobj.push_back( pt1 );
+        pt1 = SGGeodesy::direct( ref, left_hdg, 12 );
+        lightobj.push_back( Point3D::fromSGGeod(pt1) );
         normals.push_back( normal );
 
         // unit2-4
         for (int i = 0; i < 3; ++i)
         {
-            geo_direct_wgs_84 ( pt1.lat(), pt1.lon(), left_hdg,
-                                -8, &lat2, &lon2, &r );
-            pt1 = Point3D( lon2, lat2, 0.0 );
-            lightobj.push_back( pt1 );
+            pt1 = SGGeodesy::direct( pt1, left_hdg, -8 );
+            lightobj.push_back( Point3D::fromSGGeod(pt1) );
             normals.push_back( normal );
         }
     }
@@ -139,7 +112,7 @@ void LightingObj::BuildBtg( superpoly_list* lights )
         SG_LOG(SG_GENERAL, SG_DEBUG, "Generating tri-colour VASI = " << assoc_rw);
 
         // only one light here
-        lightobj.push_back( ref );
+        lightobj.push_back(  Point3D::fromSGGeod(ref) );
         normals.push_back( normal );
     }
     else