AP_Landing: Never allow cruise speed or head wind modifications to ta…

…rget airspeed when using parachute landing.

libraries/AP_Landing/AP_Landing_Slope.cpp

@@ -404,6 +404,14 @@ int32_t AP_Landing::type_slope_get_target_airspeed_cm(void)
     } else {
         target_airspeed_cm = 0.5 * (aparm.airspeed_cruise_cm * 0.01 + aparm.airspeed_min);
     }
+
+    const uint32_t max_airspeed_cm = AP_Landing::allow_max_airspeed_on_land() ? aparm.airspeed_max*100 : aparm.airspeed_cruise_cm;
+
+    // Enforce the use of landing speed for parachute landing
+    if (type == TYPE_PARACHUTE) {
+        return constrain_int32(target_airspeed_cm, target_airspeed_cm, max_airspeed_cm);
+    }
+
     switch (type_slope_stage) {
     case SlopeStage::NORMAL:
         target_airspeed_cm = aparm.airspeed_cruise_cm;
@@ -422,9 +430,6 @@ int32_t AP_Landing::type_slope_get_target_airspeed_cm(void)
     // when landing, add half of head-wind.
     const float head_wind_comp = constrain_float(wind_comp, 0.0f, 100.0f)*0.01;
     const int32_t head_wind_compensation_cm = head_wind() * head_wind_comp * 100;
-
-    const uint32_t max_airspeed_cm = AP_Landing::allow_max_airspeed_on_land() ? aparm.airspeed_max*100 : aparm.airspeed_cruise_cm;
-
     return constrain_int32(target_airspeed_cm + head_wind_compensation_cm, target_airspeed_cm, max_airspeed_cm);
 
 }