diff --git a/simgear/props/condition.cxx b/simgear/props/condition.cxx
index 014aff45..a633cacd 100644
--- a/simgear/props/condition.cxx
+++ b/simgear/props/condition.cxx
@@ -235,7 +235,6 @@ SGComparisonCondition::SGComparisonCondition (Type type, bool reverse)
 
 SGComparisonCondition::~SGComparisonCondition ()
 {
-  delete _right_value;
 }
 
 bool
@@ -267,7 +266,6 @@ void
 SGComparisonCondition::setRightProperty( SGPropertyNode *prop_root,
                                          const char * propname )
 {
-  delete _right_value;
   _right_value = 0;
   _right_property = prop_root->getNode(propname, true);
 }
@@ -276,7 +274,6 @@ void
 SGComparisonCondition::setRightValue (const SGPropertyNode *node)
 {
   _right_property = 0;
-  delete _right_value;
   _right_value = new SGPropertyNode(*node);
 }
 
diff --git a/simgear/props/condition.hxx b/simgear/props/condition.hxx
index b314cc4e..01ad8faa 100644
--- a/simgear/props/condition.hxx
+++ b/simgear/props/condition.hxx
@@ -51,7 +51,7 @@ public:
   virtual ~SGPropertyCondition ();
   virtual bool test () const { return _node->getBoolValue(); }
 private:
-  const SGPropertyNode * _node;
+  SGConstPropertyNode_ptr _node;
 };
 
 
@@ -133,9 +133,9 @@ public:
 private:
   Type _type;
   bool _reverse;
-  const SGPropertyNode * _left_property;
-  const SGPropertyNode * _right_property;
-  const SGPropertyNode * _right_value;
+  SGConstPropertyNode_ptr _left_property;
+  SGConstPropertyNode_ptr _right_property;
+  SGConstPropertyNode_ptr _right_value;
 };