diff --git a/ArduSub/flight_mode.cpp b/ArduSub/flight_mode.cpp
index df14e2c681..d8368ac274 100644
--- a/ArduSub/flight_mode.cpp
+++ b/ArduSub/flight_mode.cpp
@@ -71,6 +71,7 @@ bool Sub::set_mode(control_mode_t mode, mode_reason_t reason)
         control_mode = mode;
         control_mode_reason = reason;
         logger.Write_Mode(control_mode, control_mode_reason);
+        gcs().send_message(MSG_HEARTBEAT);
 
         // update notify object
         notify_flight_mode(control_mode);