Plane: new param LAND_THEN_NEUTRL

// @Description: When enabled, after an autoland and auto-disarm via LAND_DISARMDELAY happens then set all servos to neutral. This is helpful when an aircraft has a rough landing upside down or a crazy angle causing the servos to strain.

ArduPlane/Attitude.cpp

@@ -1084,6 +1084,18 @@ void Plane::set_servos(void)
     }
 #endif
 
+    if (g.land_then_servos_neutral &&
+            g.land_disarm_delay > 0 &&
+            auto_state.land_complete &&
+            !arming.is_armed()) {
+        // after an auto land and auto disarm, set the servos to be neutral just
+        // in case we're upside down or some crazy angle and straining the servos.
+        channel_roll->servo_out = 0;
+        channel_pitch->servo_out = 0;
+        channel_throttle->servo_out = 0;
+        channel_rudder->servo_out = 0;
+    }
+
     // send values to the PWM timers for output
     // ----------------------------------------
     if (g.rudder_only == 0) {

ArduPlane/Parameters.cpp

@@ -288,6 +288,13 @@ const AP_Param::Info Plane::var_info[] = {
     // @User: Advanced
     GSCALAR(land_disarm_delay,       "LAND_DISARMDELAY",  20),
 
+    // @Param: LAND_THEN_NEUTRL
+    // @DisplayName: Set servos to neutral after landing
+    // @Description: When enabled, after an autoland and auto-disarm via LAND_DISARMDELAY happens then set all servos to neutral. This is helpful when an aircraft has a rough landing upside down or a crazy angle causing the servos to strain.
+    // @Values: 0:Disabled, 1:Enabled
+    // @User: Advanced
+    GSCALAR(land_then_servos_neutral,       "LAND_THEN_NEUTRL",  0),
+
     // @Param: LAND_ABORT_THR
     // @DisplayName: Landing abort using throttle
     // @Description: Allow a landing abort to trigger with a throttle > 95%

ArduPlane/Parameters.h

@@ -283,6 +283,7 @@ public:
         k_param_scaling_speed,
         k_param_quadplane,
         k_param_rtl_radius,
+        k_param_land_then_servos_neutral,
 
         //
         // 210: flight modes
@@ -463,6 +464,7 @@ public:
     AP_Int32 RTL_altitude_cm;
     AP_Float land_flare_alt;
     AP_Int8 land_disarm_delay;
+    AP_Int8 land_then_servos_neutral;
     AP_Int8 land_abort_throttle_enable;
     AP_Float land_pre_flare_alt;
     AP_Float land_pre_flare_sec;