diff --git a/src/Autopilot/digitalfilter.hxx b/src/Autopilot/digitalfilter.hxx
index c1028e53b..7c923ba02 100644
--- a/src/Autopilot/digitalfilter.hxx
+++ b/src/Autopilot/digitalfilter.hxx
@@ -52,10 +52,6 @@ protected:
                             SGPropertyNode& prop_root );
     virtual void update( bool firstTime, double dt);
 
-    InputValueList _Tf;
-    InputValueList _samples;
-    InputValueList _rateOfChange;
-    InputValueList _gain;
     InitializeTo _initializeTo;
 
 public: