diff --git a/src/ATC/trafficcontrol.hxx b/src/ATC/trafficcontrol.hxx
index b1979a224..dd79e6f04 100644
--- a/src/ATC/trafficcontrol.hxx
+++ b/src/ATC/trafficcontrol.hxx
@@ -339,7 +339,7 @@ public:
     {
         return currentlyCleared;
     };
-    const double getApproachDistance() const
+    double getApproachDistance() const
     {
         return distanceToFinal;
     };