diff --git a/src/Viewer/renderer.cxx b/src/Viewer/renderer.cxx
index cc47f80b3..d982056e0 100644
--- a/src/Viewer/renderer.cxx
+++ b/src/Viewer/renderer.cxx
@@ -433,7 +433,8 @@ FGRenderer::~FGRenderer()
     }
     
     // replace the viewer's scene completely
-    getViewer()->setSceneData(new osg::Group);
+    if (getViewer())
+        getViewer()->setSceneData(new osg::Group);
     
     
 #ifdef FG_JPEG_SERVER