Plane: describe flight stages without using specific stage name

ArduPlane/Attitude.cpp

@@ -218,17 +218,15 @@ void Plane::stabilize_stick_mixing_fbw()
  */
 void Plane::stabilize_yaw(float speed_scaler)
 {
-    if (control_mode == AUTO && flight_stage == AP_Vehicle::FixedWing::FLIGHT_LAND_FINAL) {
+    if (landing.is_flaring()) {
-        // in land final setup for ground steering
+        // in flaring then enable ground steering
         steering_control.ground_steering = true;
     } else {
         // otherwise use ground steering when no input control and we
         // are below the GROUND_STEER_ALT
         steering_control.ground_steering = (channel_roll->get_control_in() == 0 && 
                                             fabsf(relative_altitude()) < g.ground_steer_alt);
-        if (control_mode == AUTO &&
+        if (landing.is_on_approach()) {
-                (flight_stage == AP_Vehicle::FixedWing::FLIGHT_LAND_APPROACH ||
-                flight_stage == AP_Vehicle::FixedWing::FLIGHT_LAND_PREFLARE)) {
             // don't use ground steering on landing approach
             steering_control.ground_steering = false;
         }
@@ -237,12 +235,11 @@ void Plane::stabilize_yaw(float speed_scaler)
 
     /*
       first calculate steering_control.steering for a nose or tail
-      wheel.
+      wheel. We use "course hold" mode for the rudder when either performing
-      We use "course hold" mode for the rudder when either in the
+      a flare (when the wings are held level) or when in course hold in
-      final stage of landing (when the wings are help level) or when
+      FBWA mode (when we are below GROUND_STEER_ALT)
-      in course hold in FBWA mode (when we are below GROUND_STEER_ALT)
      */
-    if ((control_mode == AUTO && flight_stage == AP_Vehicle::FixedWing::FLIGHT_LAND_FINAL) ||
+    if (landing.is_flaring() ||
         (steer_state.hold_course_cd != -1 && steering_control.ground_steering)) {
         calc_nav_yaw_course();
     } else if (steering_control.ground_steering) {

ArduPlane/GCS_Mavlink.cpp

@@ -1344,8 +1344,6 @@ void GCS_MAVLINK_Plane::handleMessage(mavlink_message_t* msg)
         case MAV_CMD_DO_GO_AROUND:
             result = MAV_RESULT_FAILED;
 
-            //Not allowing go around at FLIGHT_LAND_FINAL stage on purpose --
-            //if plane is close to the ground a go around could be dangerous.
             if (plane.landing.in_progress) {
                 // Initiate an aborted landing. This will trigger a pitch-up and
                 // climb-out to a safe altitude holding heading then one of the

ArduPlane/altitude.cpp

@@ -29,12 +29,11 @@ void Plane::adjust_altitude_target()
         control_mode == CRUISE) {
         return;
     }
-    if (flight_stage == AP_Vehicle::FixedWing::FLIGHT_LAND_FINAL) {
+    if (landing.is_flaring()) {
-        // in land final TECS uses TECS_LAND_SINK as a target sink
+        // during a landing flare, use TECS_LAND_SINK as a target sink
         // rate, and ignores the target altitude
         set_target_altitude_location(next_WP_loc);
-    } else if (flight_stage == AP_Vehicle::FixedWing::FLIGHT_LAND_APPROACH ||
+    } else if (landing.is_on_approach()) {
-            flight_stage == AP_Vehicle::FixedWing::FLIGHT_LAND_PREFLARE) {
         landing.setup_landing_glide_slope(prev_WP_loc, next_WP_loc, current_loc, target_altitude.offset_cm);
         landing.adjust_landing_slope_for_rangefinder_bump(rangefinder_state, prev_WP_loc, next_WP_loc, current_loc, auto_state.wp_distance, target_altitude.offset_cm);
     } else if (reached_loiter_target()) {

ArduPlane/geofence.cpp

@@ -310,7 +310,7 @@ void Plane::geofence_check(bool altitude_check_only)
     struct Location loc;
 
     // Never trigger a fence breach in the final stage of landing
-    if (flight_stage == AP_Vehicle::FixedWing::FLIGHT_LAND_FINAL || flight_stage == AP_Vehicle::FixedWing::FLIGHT_LAND_PREFLARE) {
+    if (landing.is_expecting_impact()) {
         return;
     }
 

ArduPlane/is_flying.cpp

@@ -70,6 +70,10 @@ void Plane::update_is_flying_5Hz(void)
                 crash_state.impact_detected = false;
             }
 
+            if (landing.is_on_approach() && fabsf(auto_state.sink_rate) > 0.2f) {
+                is_flying_bool = true;
+            }
+
             switch (flight_stage)
             {
             case AP_Vehicle::FixedWing::FLIGHT_TAKEOFF:
@@ -89,16 +93,6 @@ void Plane::update_is_flying_5Hz(void)
                 // TODO: detect ground impacts
                 break;
 
-            case AP_Vehicle::FixedWing::FLIGHT_LAND_APPROACH:
-                if (fabsf(auto_state.sink_rate) > 0.2f) {
-                    is_flying_bool = true;
-                }
-                break;
-
-            case AP_Vehicle::FixedWing::FLIGHT_LAND_PREFLARE:
-            case AP_Vehicle::FixedWing::FLIGHT_LAND_FINAL:
-                break;
-
             case AP_Vehicle::FixedWing::FLIGHT_ABORT_LAND:
                 if (auto_state.sink_rate < -0.5f) {
                     // steep climb
@@ -114,9 +108,7 @@ void Plane::update_is_flying_5Hz(void)
         // when disarmed assume not flying and need overwhelming evidence that we ARE flying
         is_flying_bool = airspeed_movement && gps_confirmed_movement;
 
-        if ((control_mode == AUTO) &&
+        if ((flight_stage == AP_Vehicle::FixedWing::FLIGHT_TAKEOFF) || landing.is_flaring()) {
-            ((flight_stage == AP_Vehicle::FixedWing::FLIGHT_TAKEOFF) ||
-             (flight_stage == AP_Vehicle::FixedWing::FLIGHT_LAND_FINAL)) ) {
             is_flying_bool = false;
         }
     }
@@ -205,6 +197,39 @@ void Plane::crash_detection_update(void)
 
     if (!is_flying() && arming.is_armed())
     {
+        if (landing.is_expecting_impact()) {
+            // We should be nice and level-ish in this flight stage. If not, we most
+            // likely had a crazy landing. Throttle is inhibited already at the flare
+            // but go ahead and notify GCS and perform any additional post-crash actions.
+            // Declare a crash if we are oriented more that 60deg in pitch or roll
+            if (!crash_state.checkedHardLanding && // only check once
+                been_auto_flying &&
+                (labs(ahrs.roll_sensor) > 6000 || labs(ahrs.pitch_sensor) > 6000)) {
+                crashed = true;
+                crash_state.debounce_time_total_ms = CRASH_DETECTION_DELAY_MS;
+
+                // did we "crash" within 75m of the landing location? Probably just a hard landing
+                crashed_near_land_waypoint =
+                        get_distance(current_loc, mission.get_current_nav_cmd().content.location) < 75;
+
+                // trigger hard landing event right away, or never again. This inhibits a false hard landing
+                // event when, for example, a minute after a good landing you pick the plane up and
+                // this logic is still running and detects the plane is on its side as you carry it.
+                crash_state.debounce_timer_ms = now_ms + CRASH_DETECTION_DELAY_MS;
+            }
+
+            crash_state.checkedHardLanding = true;
+
+        } else if (landing.is_on_approach()) {
+            // when altitude gets low, we automatically flare so ground crashes
+            // most likely can not be triggered from here. However,
+            // a crash into a tree would be caught here.
+            if (been_auto_flying) {
+                crashed = true;
+                crash_state.debounce_time_total_ms = CRASH_DETECTION_DELAY_MS;
+            }
+
+        } else {
             switch (flight_stage)
             {
             case AP_Vehicle::FixedWing::FLIGHT_TAKEOFF:
@@ -231,44 +256,10 @@ void Plane::crash_detection_update(void)
                 crashed = false;
                 break;
 
-        case AP_Vehicle::FixedWing::FLIGHT_LAND_APPROACH:
-            if (been_auto_flying) {
-                crashed = true;
-                crash_state.debounce_time_total_ms = CRASH_DETECTION_DELAY_MS;
-            }
-            // when altitude gets low, we automatically progress to FLIGHT_LAND_FINAL
-            // so ground crashes most likely can not be triggered from here. However,
-            // a crash into a tree would be caught here.
-            break;
-
-        case AP_Vehicle::FixedWing::FLIGHT_LAND_PREFLARE:
-        case AP_Vehicle::FixedWing::FLIGHT_LAND_FINAL:
-            // We should be nice and level-ish in this flight stage. If not, we most
-            // likely had a crazy landing. Throttle is inhibited already at the flare
-            // but go ahead and notify GCS and perform any additional post-crash actions.
-            // Declare a crash if we are oriented more that 60deg in pitch or roll
-            if (!crash_state.checkedHardLanding && // only check once
-                been_auto_flying &&
-                (labs(ahrs.roll_sensor) > 6000 || labs(ahrs.pitch_sensor) > 6000)) {
-                crashed = true;
-                crash_state.debounce_time_total_ms = CRASH_DETECTION_DELAY_MS;
-
-                // did we "crash" within 75m of the landing location? Probably just a hard landing
-                crashed_near_land_waypoint =
-                        get_distance(current_loc, mission.get_current_nav_cmd().content.location) < 75;
-
-                // trigger hard landing event right away, or never again. This inhibits a false hard landing
-                // event when, for example, a minute after a good landing you pick the plane up and
-                // this logic is still running and detects the plane is on its side as you carry it.
-                crash_state.debounce_timer_ms = now_ms + CRASH_DETECTION_DELAY_MS;
-            }
-
-            crash_state.checkedHardLanding = true;
-            break;
-
             default:
                 break;
             } // switch
+        }
     } else {
         crash_state.checkedHardLanding = false;
     }

ArduPlane/servos.cpp

@@ -417,18 +417,14 @@ void Plane::set_servos_controlled(void)
         min_throttle = 0;
     }
     
-    if (control_mode == AUTO) {
-        if (flight_stage == AP_Vehicle::FixedWing::FLIGHT_LAND_FINAL) {
-            min_throttle = 0;
-        }
-        
     if (flight_stage == AP_Vehicle::FixedWing::FLIGHT_TAKEOFF || flight_stage == AP_Vehicle::FixedWing::FLIGHT_ABORT_LAND) {
         if(aparm.takeoff_throttle_max != 0) {
             max_throttle = aparm.takeoff_throttle_max;
         } else {
             max_throttle = aparm.throttle_max;
         }
-        }
+    } else if (landing.is_flaring()) {
+        min_throttle = 0;
     }
     
     // apply watt limiter
@@ -499,6 +495,10 @@ void Plane::set_servos_flaps(void)
             auto_flap_percent = g.flap_1_percent;
         } //else flaps stay at default zero deflection
 
+        if (landing.in_progress && landing.get_flap_percent() != 0) {
+            auto_flap_percent = landing.get_flap_percent();
+        }
+
         /*
           special flap levels for takeoff and landing. This works
           better than speed based flaps as it leads to less
@@ -518,13 +518,6 @@ void Plane::set_servos_flaps(void)
                     auto_flap_percent = g.takeoff_flap_percent;
                 }
                 break;
-            case AP_Vehicle::FixedWing::FLIGHT_LAND_APPROACH:
-            case AP_Vehicle::FixedWing::FLIGHT_LAND_PREFLARE:
-            case AP_Vehicle::FixedWing::FLIGHT_LAND_FINAL:
-                if (landing.get_flap_percent() != 0) {
-                    auto_flap_percent = landing.get_flap_percent();
-                }
-                break;
             default:
                 break;
             }