Copter: Guided Angle init Z controller on time out

ArduCopter/mode_guided.cpp

@@ -833,8 +833,12 @@ void ModeGuided::angle_control_run()
         pitch_in = 0.0f;
         climb_rate_cms = 0.0f;
         yaw_rate_in = 0.0f;
+        if (guided_angle_state.use_thrust) {
+            // initialise vertical velocity controller
+            pos_control->init_z_controller();
             guided_angle_state.use_thrust = false;
         }
+    }
 
     // interpret positive climb rate or thrust as triggering take-off
     const bool positive_thrust_or_climbrate = is_positive(guided_angle_state.use_thrust ? guided_angle_state.thrust : climb_rate_cms);