diff --git a/gui/dialogs/atc-ai.xml b/gui/dialogs/atc-ai.xml
index e9b67fdac..da8dcaa56 100755
--- a/gui/dialogs/atc-ai.xml
+++ b/gui/dialogs/atc-ai.xml
@@ -21,7 +21,7 @@
   <width>20</width>
   <height>20</height>
   <label>Enable ATC</label>
-  <property>/sim/ATC/enabled</property>
+  <property>/sim/atc/enabled</property>
  </checkbox>
 
  <checkbox>
diff --git a/preferences.xml b/preferences.xml
index a490fe10d..56db1e400 100644
--- a/preferences.xml
+++ b/preferences.xml
@@ -281,9 +281,9 @@ Started September 2000 by David Megginson, david@megginson.com
    <view type="int">1</view>
   </replay>
   
-  <ATC>
+  <atc>
    <enabled type="bool">true</enabled>
-  </ATC>
+  </atc>
 
   <ai-traffic>
    <enabled type="bool">false</enabled>