From 8d94e58ec92eeff708f4b91d267166642f07e519 Mon Sep 17 00:00:00 2001
From: Hwurzburg <hwurzburg@yahoo.com>
Date: Sun, 24 Oct 2021 00:20:43 -0500
Subject: [PATCH] ArduPlane: add RC option to plane for emergency remote
 landing that forces FS actions to FBWA

---
 ArduPlane/Plane.h        |  3 +++
 ArduPlane/RC_Channel.cpp | 14 ++++++++++++++
 ArduPlane/events.cpp     |  8 ++++++++
 3 files changed, 25 insertions(+)

diff --git a/ArduPlane/Plane.h b/ArduPlane/Plane.h
index ba7a32096c..b1c6182430 100644
--- a/ArduPlane/Plane.h
+++ b/ArduPlane/Plane.h
@@ -1100,6 +1100,9 @@ private:
     void update_soaring();
 #endif
 
+    // RC_Channel.cpp
+    bool emergency_landing;
+
     // vehicle specific waypoint info helpers
     bool get_wp_distance_m(float &distance) const override;
     bool get_wp_bearing_deg(float &bearing) const override;
diff --git a/ArduPlane/RC_Channel.cpp b/ArduPlane/RC_Channel.cpp
index 93540d7f9e..8a3dcf6df8 100644
--- a/ArduPlane/RC_Channel.cpp
+++ b/ArduPlane/RC_Channel.cpp
@@ -164,6 +164,7 @@ void RC_Channel_Plane::init_aux_function(const RC_Channel::aux_func_t ch_option,
     case AUX_FUNC::ARMDISARM_AIRMODE:
 #endif
     case AUX_FUNC::TRIM_TO_CURRENT_SERVO_RC:
+    case AUX_FUNC::EMERGENCY_LANDING_EN:
         break;
 
     case AUX_FUNC::SOARING:
@@ -354,6 +355,19 @@ case AUX_FUNC::ARSPD_CALIBRATE:
         }
         break;
 
+    case AUX_FUNC::EMERGENCY_LANDING_EN:
+        switch (ch_flag) {
+        case AuxSwitchPos::HIGH:
+            plane.emergency_landing = true;
+            break;
+        case AuxSwitchPos::MIDDLE:
+            break;
+        case AuxSwitchPos::LOW:
+            plane.emergency_landing = false;
+            break;
+        }
+        break;
+
 
     default:
         return RC_Channel::do_aux_function(ch_option, ch_flag);
diff --git a/ArduPlane/events.cpp b/ArduPlane/events.cpp
index bc4a500825..ae6a60e550 100644
--- a/ArduPlane/events.cpp
+++ b/ArduPlane/events.cpp
@@ -33,6 +33,10 @@ void Plane::failsafe_short_on_event(enum failsafe_state fstype, ModeReason reaso
     case Mode::Number::TRAINING:
         failsafe.saved_mode_number = control_mode->mode_number();
         failsafe.saved_mode_set = true;
+        if(plane.emergency_landing) {
+            set_mode(mode_fbwa, reason); // emergency landing switch overrides normal action to allow out of range landing
+            break;
+        }
         if(g.fs_action_short == FS_ACTION_SHORT_FBWA) {
             set_mode(mode_fbwa, reason);
         } else if (g.fs_action_short == FS_ACTION_SHORT_FBWB) {
@@ -116,6 +120,10 @@ void Plane::failsafe_long_on_event(enum failsafe_state fstype, ModeReason reason
     case Mode::Number::CIRCLE:
     case Mode::Number::LOITER:
     case Mode::Number::THERMAL:
+        if(plane.emergency_landing) {
+            set_mode(mode_fbwa, reason); // emergency landing switch overrides normal action to allow out of range landing
+            break;
+        }
         if(g.fs_action_long == FS_ACTION_LONG_PARACHUTE) {
 #if PARACHUTE == ENABLED
             parachute_release();