diff --git a/simgear/props/props.cxx b/simgear/props/props.cxx
index 673cde4c..2f26f2a6 100644
--- a/simgear/props/props.cxx
+++ b/simgear/props/props.cxx
@@ -2030,12 +2030,15 @@ SGPropertyNode::untie (const char * relative_path)
 }
 
 void
-SGPropertyNode::addChangeListener (SGPropertyChangeListener * listener)
+SGPropertyNode::addChangeListener (SGPropertyChangeListener * listener,
+                                   bool initial)
 {
   if (_listeners == 0)
     _listeners = new vector<SGPropertyChangeListener*>;
   _listeners->push_back(listener);
   listener->register_property(this);
+  if (initial)
+    listener->valueChanged(this);
 }
 
 void
diff --git a/simgear/props/props.hxx b/simgear/props/props.hxx
index fb04b6bf..332d47a2 100644
--- a/simgear/props/props.hxx
+++ b/simgear/props/props.hxx
@@ -1097,9 +1097,11 @@ public:
 
 
   /**
-   * Add a change listener to the property.
+   * Add a change listener to the property. If "initial" is set call the
+   * listener initially.
    */
-  void addChangeListener (SGPropertyChangeListener * listener);
+  void addChangeListener (SGPropertyChangeListener * listener,
+                          bool initial = false);
 
 
   /**