diff --git a/libraries/AP_Vehicle/ModeReason.h b/libraries/AP_Vehicle/ModeReason.h
index bcee6a0f0edb20..c229f8911f9391 100644
--- a/libraries/AP_Vehicle/ModeReason.h
+++ b/libraries/AP_Vehicle/ModeReason.h
@@ -62,4 +62,5 @@ enum class ModeReason : uint8_t {
   FRSKY_COMMAND = 42,
   FENCE_RETURN_PREVIOUS_MODE = 43,
   QRTL_INSTEAD_OF_RTL = 44,
+  AUTO_RTL_EXIT = 45,
 };