diff --git a/src/Viewer/fg_os_osgviewer.cxx b/src/Viewer/fg_os_osgviewer.cxx
index d754c5f98..22526d0db 100644
--- a/src/Viewer/fg_os_osgviewer.cxx
+++ b/src/Viewer/fg_os_osgviewer.cxx
@@ -318,7 +318,7 @@ int fgOSMainLoop()
         if (idleFunc)
             (*idleFunc)();
         globals->get_renderer()->update();
-        viewer->frame();
+        viewer->frame( globals->get_sim_time_sec() );
     }
     
     return status;