diff --git a/Tools/AP_Periph/GCS_MAVLink.h b/Tools/AP_Periph/GCS_MAVLink.h
index fa3366ed11..7472fc005f 100644
--- a/Tools/AP_Periph/GCS_MAVLink.h
+++ b/Tools/AP_Periph/GCS_MAVLink.h
@@ -41,6 +41,7 @@ protected:
 
     void send_nav_controller_output() const override {};
     void send_pid_tuning() override {};
+    virtual uint8_t send_available_mode(uint8_t index) const override { return 0; }
 };
 
 /*