diff --git a/libraries/SRV_Channel/SRV_Channel.h b/libraries/SRV_Channel/SRV_Channel.h
index a6906972fb..ee04aa6a4b 100644
--- a/libraries/SRV_Channel/SRV_Channel.h
+++ b/libraries/SRV_Channel/SRV_Channel.h
@@ -121,6 +121,7 @@ public:
         k_dspoilerLeft2         = 86,           ///< differential spoiler 2 (left wing)
         k_dspoilerRight2        = 87,           ///< differential spoiler 2 (right wing)
         k_winch                 = 88,
+        k_mainsail_sheet        = 89,           ///< Main Sail control via sheet
         k_nr_aux_servo_functions         ///< This must be the last enum value (only add new values _before_ this one)
     } Aux_servo_function_t;