[bugfix] Fix: RC really lost procedure only active when launch has be…

…en pressed. When not launched, the RC_LOST_MODE is not set and throttle is kept from the last manual input. Solves #2286

sw/airborne/firmwares/fixedwing/autopilot_static.c

@@ -114,17 +114,21 @@ void autopilot_static_on_rc_frame(void)
   uint8_t mode_changed = false;
   copy_from_to_fbw();
 
-  /* really_lost is true if we lost RC in MANUAL or AUTO1 */
-  uint8_t really_lost = bit_is_set(imcu_get_status(), STATUS_RADIO_REALLY_LOST) &&
+  /* rc_lost_while_in_use is true if we lost RC in MANUAL or AUTO1 */
+  uint8_t rc_lost_while_in_use = bit_is_set(imcu_get_status(), STATUS_RADIO_REALLY_LOST) &&
                         (autopilot_get_mode() == AP_MODE_AUTO1 || autopilot_get_mode() == AP_MODE_MANUAL);
 
+  /* RC_LOST_MODE defaults to AP_MODE_HOME, but it can also be set to NAV_MODE_NAV or MANUAL when the RC receiver is well configured to send failsafe commands */
+  if (rc_lost_while_in_use) { // Always: no exceptions!
+    mode_changed = autopilot_set_mode(RC_LOST_MODE);
+  }
+
+  /* If in-flight, with good GPS but too far, then activate HOME mode
+   * In MANUAL with good RC, FBW will allow to override. */
   if (autopilot_get_mode() != AP_MODE_HOME && autopilot_get_mode() != AP_MODE_GPS_OUT_OF_ORDER && autopilot.launch) {
     if (too_far_from_home || datalink_lost() || higher_than_max_altitude()) {
       mode_changed = autopilot_set_mode(AP_MODE_HOME);
     }
-    if (really_lost) {
-      mode_changed = autopilot_set_mode(RC_LOST_MODE);
-    }
   }
   if (bit_is_set(imcu_get_status(), AVERAGED_CHANNELS_SENT)) {
     bool pprz_mode_changed = pprz_mode_update();

sw/airborne/firmwares/fixedwing/nav.c

@@ -424,7 +424,12 @@ void nav_home(void)
   NavCircleWaypoint(WP_HOME, FAILSAFE_HOME_RADIUS);
   /** Nominal speed */
   nav_pitch = 0.;
-  v_ctl_mode = V_CTL_MODE_AUTO_ALT;
+  if (autopilot_in_flight() && autopilot.launch) {
+    v_ctl_mode = V_CTL_MODE_AUTO_ALT;
+  } else {
+    v_ctl_mode = V_CTL_MODE_AUTO_THROTTLE;
+    v_ctl_throttle_setpoint = 0;
+  }
   nav_altitude = ground_alt + HOME_MODE_HEIGHT;
   compute_dist2_to_home();
   dist2_to_wp = dist2_to_home;