diff --git a/src/AutoPilotPlugins/Common/ESP8266ComponentController.h b/src/AutoPilotPlugins/Common/ESP8266ComponentController.h
index 2f637cc..7f41ca7 100644
--- a/src/AutoPilotPlugins/Common/ESP8266ComponentController.h
+++ b/src/AutoPilotPlugins/Common/ESP8266ComponentController.h
@@ -63,7 +63,7 @@ public:
     QStringList     wifiChannels    () { return _channels; }
     QStringList     baudRates       () { return _baudRates; }
     int             baudIndex       ();
-    bool            busy            () { return _waitType != WAIT_FOR_NOTHING; }
+    bool            busy            () const{ return _waitType != WAIT_FOR_NOTHING; }
     Vehicle*        vehicle         () { return _vehicle; }
 
     void        setWifiSSID         (QString id);