diff --git a/ArduPlane/quadplane.cpp b/ArduPlane/quadplane.cpp
index ccaa9010a2..702b52f036 100644
--- a/ArduPlane/quadplane.cpp
+++ b/ArduPlane/quadplane.cpp
@@ -1726,6 +1726,7 @@ void QuadPlane::vtol_position_controller(void)
     float ekfGndSpdLimit, ekfNavVelGainScaler;    
     ahrs.getEkfControlLimits(ekfGndSpdLimit, ekfNavVelGainScaler);
 
+    // horizontal position control
     switch (poscontrol.state) {
 
     case QPOS_POSITION1: {