diff --git a/simgear/props/props.cxx b/simgear/props/props.cxx
index fce6e8ab..12a8fe83 100644
--- a/simgear/props/props.cxx
+++ b/simgear/props/props.cxx
@@ -1615,8 +1615,12 @@ bool SGPropertyNode::tie (const SGRawValue<const char *> &rawValue,
     _tied = true;
     _value.val = rawValue.clone();
 
-    if (useDefault)
+    if (useDefault) {
+        int save_attributes = getAttributes();
+        setAttribute( WRITE, true );
         setStringValue(old_val.c_str());
+        setAttributes( save_attributes );
+    }
 
     return true;
 }
diff --git a/simgear/props/props.hxx b/simgear/props/props.hxx
index a80fc10a..e870f440 100644
--- a/simgear/props/props.hxx
+++ b/simgear/props/props.hxx
@@ -1786,8 +1786,12 @@ bool SGPropertyNode::tie(const SGRawValue<T> &rawValue, bool useDefault)
         _type = EXTENDED;
     _tied = true;
     _value.val = rawValue.clone();
-    if (useDefault)
+    if (useDefault) {
+        int save_attributes = getAttributes();
+        setAttribute( WRITE, true );
         setValue(old_val);
+        setAttributes( save_attributes );
+    }
     return true;
 }