Plane: fixed tilt transition with binary tilt servo

once the tilt is fully fwd then force transition as done at any
airspeed

ArduPlane/quadplane.cpp

@@ -1011,6 +1011,11 @@ void QuadPlane::update_transition(void)
         assisted_flight = false;
     }
 
+    // if rotors are fully forward then we are not transitioning
+    if (tiltrotor_fully_fwd()) {
+        transition_state = TRANSITION_DONE;
+    }
+    
     if (transition_state < TRANSITION_TIMER) {
         // set a single loop pitch limit in TECS
         if (plane.ahrs.groundspeed() < 3) {

ArduPlane/quadplane.h

@@ -323,6 +323,7 @@ private:
     void tiltrotor_continuous_update(void);
     void tiltrotor_binary_update(void);
     void tilt_compensate(float *thrust, uint8_t num_motors);
+    bool tiltrotor_fully_fwd(void);
 
     void afs_terminate(void);
     bool guided_mode_enabled(void);

ArduPlane/tiltrotor.cpp

@@ -229,3 +229,14 @@ void QuadPlane::tilt_compensate(float *thrust, uint8_t num_motors)
         }
     }
 }
+
+/*
+  return true if the rotors are fully tilted forward
+ */
+bool QuadPlane::tiltrotor_fully_fwd(void)
+{
+    if (tilt.tilt_mask <= 0) {
+        return false;
+    }
+    return (tilt.current_tilt >= 1);
+}