diff --git a/libraries/AP_Vehicle/AP_Vehicle.cpp b/libraries/AP_Vehicle/AP_Vehicle.cpp
index 24644c4726dbc..f07e6382f8f7b 100644
--- a/libraries/AP_Vehicle/AP_Vehicle.cpp
+++ b/libraries/AP_Vehicle/AP_Vehicle.cpp
@@ -355,6 +355,12 @@ void AP_Vehicle::update_dynamic_notch_at_specified_rate()
     }
 }
 
+void AP_Vehicle::notify_no_such_mode(uint8_t mode_number)
+{
+    GCS_SEND_TEXT(MAV_SEVERITY_WARNING,"No such mode %u", mode_number);
+    AP::logger().Write_Error(LogErrorSubsystem::FLIGHT_MODE, LogErrorCode(mode_number));
+}
+
 // reboot the vehicle in an orderly manner, doing various cleanups and
 // flashing LEDs as appropriate
 void AP_Vehicle::reboot(bool hold_in_bootloader)
diff --git a/libraries/AP_Vehicle/AP_Vehicle.h b/libraries/AP_Vehicle/AP_Vehicle.h
index 155d0356664d9..d6e609cec33a1 100644
--- a/libraries/AP_Vehicle/AP_Vehicle.h
+++ b/libraries/AP_Vehicle/AP_Vehicle.h
@@ -85,6 +85,12 @@ class AP_Vehicle : public AP_HAL::HAL::Callbacks {
         return control_mode_reason;
     }
 
+    // perform any notifications required to indicate a mode change
+    // failed due to a bad mode number being supplied.  This can
+    // happen for many reasons - bad mavlink packet and bad mode
+    // parameters for example.
+    void notify_no_such_mode(uint8_t mode_number);
+
     /*
       common parameters for fixed wing aircraft
      */