diff --git a/ArduCopter/Log.cpp b/ArduCopter/Log.cpp
index 49ced3795d..2c1b1b1fa9 100644
--- a/ArduCopter/Log.cpp
+++ b/ArduCopter/Log.cpp
@@ -453,6 +453,22 @@ const struct LogStructure Copter::log_structure[] = {
     LOG_COMMON_STRUCTURES,
     { LOG_PARAMTUNE_MSG, sizeof(log_ParameterTuning),
       "PTUN", "QBfff",         "TimeUS,Param,TunVal,TunMin,TunMax", "s----", "F----" },
+
+// @LoggerMessage: CTUN
+// @Description: Control Tuning information
+// @Field: TimeUS: microseconds since system startup
+// @Field: ThI: throttle input
+// @Field: ThO: throttle output
+// @Field: ThH: calculated hover throttle
+// @Field: DAlt: desired altitude
+// @Field: Alt: achieved altitude
+// @Field: BAlt: barometric altitude
+// @Field: DSAlt: desired rangefinder altitude
+// @Field: SAlt: achived rangefinder altitude
+// @Field: TAlt: terrain altitude
+// @Field: DCRt: desired climb rate
+// @Field: CRt: climb rate
+
     { LOG_CONTROL_TUNING_MSG, sizeof(log_Control_Tuning),
       "CTUN", "Qffffffefffhh", "TimeUS,ThI,ABst,ThO,ThH,DAlt,Alt,BAlt,DSAlt,SAlt,TAlt,DCRt,CRt", "s----mmmmmmnn", "F----00B000BB" },
     { LOG_MOTBATT_MSG, sizeof(log_MotBatt),