diff --git a/ArduCopter/ArduCopter.pde b/ArduCopter/ArduCopter.pde
index 3f3fec392c..084de2b7af 100644
--- a/ArduCopter/ArduCopter.pde
+++ b/ArduCopter/ArduCopter.pde
@@ -1087,6 +1087,8 @@ static void one_hz_loop()
         }
     }
 
+    gcs_send_message(MSG_ARMMASK);
+
     // auto disarm checks
     auto_disarm_check();
 
diff --git a/ArduCopter/GCS_Mavlink.pde b/ArduCopter/GCS_Mavlink.pde
index d1cad8834c..2bc4b2bc95 100644
--- a/ArduCopter/GCS_Mavlink.pde
+++ b/ArduCopter/GCS_Mavlink.pde
@@ -669,6 +669,10 @@ bool GCS_MAVLINK::try_send_message(enum ap_message id)
     case MSG_MAG_CAL_REPORT:
         compass.send_mag_cal_report(chan);
         break;
+
+    case MSG_ARMMASK:
+        mavlink_msg_named_value_int_send(chan, millis(), "ARMMASK", get_ready_to_arm_mode_mask());
+        break;
     }
 
     return true;