Plane: rely on flight stage to know if we're doing auto_land in TECS

ArduPlane/ArduPlane.cpp

@@ -870,25 +870,27 @@ void Plane::update_alt()
 
     update_flight_stage();
 
-    bool is_doing_auto_land = (control_mode == AUTO) && (mission.get_current_nav_cmd().id == MAV_CMD_NAV_LAND);
-    float distance_beyond_land_wp = 0;
-    if (is_doing_auto_land && location_passed_point(current_loc, prev_WP_loc, next_WP_loc)) {
-        distance_beyond_land_wp = get_distance(current_loc, next_WP_loc);
-    }
-
     if (auto_throttle_mode && !throttle_suppressed) {        
 
-        // set Flight stage for controller. If not in AUTO then assume normal operation.
+        bool is_doing_auto_land = false;
-        // this prevents TECS from being stuck in the wrong stage if you switch from
+        float distance_beyond_land_wp = 0;
-        // AUTO to, say, FBWB during an aborted landing
+
-        AP_SpdHgtControl::FlightStage fs = flight_stage;
+        switch (flight_stage) {
-        if (control_mode != AUTO) {
+        case AP_SpdHgtControl::FLIGHT_LAND_APPROACH:
-            fs = AP_SpdHgtControl::FLIGHT_NORMAL;
+        case AP_SpdHgtControl::FLIGHT_LAND_PREFLARE:
+        case AP_SpdHgtControl::FLIGHT_LAND_FINAL:
+            is_doing_auto_land = true;
+            if (location_passed_point(current_loc, prev_WP_loc, next_WP_loc)) {
+                distance_beyond_land_wp = get_distance(current_loc, next_WP_loc);
+            }
+            break;
+        default:
+            break;
         }
 
         SpdHgt_Controller->update_pitch_throttle(relative_target_altitude_cm(),
                                                  target_airspeed_cm,
-                                                 fs,
+                                                 flight_stage,
                                                  is_doing_auto_land,
                                                  distance_beyond_land_wp,
                                                  auto_state.takeoff_pitch_cd,
@@ -940,6 +942,9 @@ void Plane::update_flight_stage(void)
                 set_flight_stage(AP_SpdHgtControl::FLIGHT_NORMAL);
             }
         } else {
+            // If not in AUTO then assume normal operation for normal TECS operation.
+            // This prevents TECS from being stuck in the wrong stage if you switch from
+            // AUTO to, say, FBWB during a landing, an aborted landing or takeoff.
             set_flight_stage(AP_SpdHgtControl::FLIGHT_NORMAL);
         }
     } else if (quadplane.in_vtol_mode() ||