Plane: added note on type of airspeed in docs

ArduPlane/Parameters.pde

@@ -250,7 +250,7 @@ const AP_Param::Info var_info[] PROGMEM = {
 
     // @Param: ARSPD_FBW_MIN
     // @DisplayName: Fly By Wire Minimum Airspeed
-    // @Description: Airspeed corresponding to minimum throttle in auto throttle modes (FBWB, CRUISE, AUTO, GUIDED, LOITER, CIRCLE and RTL)
+    // @Description: Airspeed corresponding to minimum throttle in auto throttle modes (FBWB, CRUISE, AUTO, GUIDED, LOITER, CIRCLE and RTL). This is a calibrated (apparent) airspeed.
     // @Units: m/s
     // @Range: 5 50
     // @Increment: 1
@@ -259,7 +259,7 @@ const AP_Param::Info var_info[] PROGMEM = {
 
     // @Param: ARSPD_FBW_MAX
     // @DisplayName: Fly By Wire Maximum Airspeed
-    // @Description: Airspeed corresponding to maximum throttle in auto throttle modes (FBWB, CRUISE, AUTO, GUIDED, LOITER, CIRCLE and RTL)
+    // @Description: Airspeed corresponding to maximum throttle in auto throttle modes (FBWB, CRUISE, AUTO, GUIDED, LOITER, CIRCLE and RTL). This is a calibrated (apparent) airspeed.
     // @Units: m/s
     // @Range: 5 50
     // @Increment: 1
@@ -585,7 +585,7 @@ const AP_Param::Info var_info[] PROGMEM = {
 
     // @Param: TRIM_ARSPD_CM
     // @DisplayName: Target airspeed
-    // @Description: Airspeed in cm/s to aim for when airspeed is enabled in auto mode
+    // @Description: Airspeed in cm/s to aim for when airspeed is enabled in auto mode. This is a calibrated (apparent) airspeed.
     // @Units: cm/s
     // @User: User
     GSCALAR(airspeed_cruise_cm,     "TRIM_ARSPD_CM",  AIRSPEED_CRUISE_CM),