diff --git a/libraries/AP_Arming/AP_Arming.h b/libraries/AP_Arming/AP_Arming.h
index 17ec0aed86..4d031ae9be 100644
--- a/libraries/AP_Arming/AP_Arming.h
+++ b/libraries/AP_Arming/AP_Arming.h
@@ -164,7 +164,7 @@ protected:
 
     bool manual_transmitter_checks(bool report);
 
-    bool mission_checks(bool report);
+    virtual bool mission_checks(bool report);
 
     bool rangefinder_checks(bool report);