diff --git a/libraries/AC_AutoTune/AC_AutoTune_Heli.h b/libraries/AC_AutoTune/AC_AutoTune_Heli.h
index 133047a12d..9ba8596897 100644
--- a/libraries/AC_AutoTune/AC_AutoTune_Heli.h
+++ b/libraries/AC_AutoTune/AC_AutoTune_Heli.h
@@ -20,6 +20,7 @@
 
 #include "AC_AutoTune.h"
 #include <AP_Math/chirp.h>
+#include <GCS_MAVLink/GCS.h>
 
 #include <AP_Scheduler/AP_Scheduler.h>