diff --git a/libraries/RC_Channel/RC_Channel_aux.cpp b/libraries/RC_Channel/RC_Channel_aux.cpp
index b440edf073..28a434d897 100644
--- a/libraries/RC_Channel/RC_Channel_aux.cpp
+++ b/libraries/RC_Channel/RC_Channel_aux.cpp
@@ -22,6 +22,7 @@ const AP_Param::GroupInfo RC_Channel_aux::var_info[] = {
 RC_Channel_aux *RC_Channel_aux::_aux_channels[RC_AUX_MAX_CHANNELS];
 uint64_t RC_Channel_aux::_function_mask[2];
 bool RC_Channel_aux::_initialised;
+bool RC_Channel_aux::_disable_passthrough;
 
 void
 RC_Channel_aux::set_function_mask(uint8_t fn)
@@ -47,10 +48,18 @@ RC_Channel_aux::output_ch(void)
     case k_none:                // disabled
         return;
     case k_manual:              // manual
-        set_radio_out(get_radio_in());
+        if (_disable_passthrough) {
+            set_radio_out(get_radio_trim());
+        } else {
+            set_radio_out(get_radio_in());
+        }
         break;
     case k_rcin1 ... k_rcin16: // rc pass-thru
-        set_radio_out(hal.rcin->read(function-k_rcin1));
+        if (_disable_passthrough) {
+            set_radio_out(get_radio_trim());
+        } else {
+            set_radio_out(hal.rcin->read(function-k_rcin1));
+        }
         break;
     case k_motor1 ... k_motor8:
         // handled by AP_Motors::rc_write()
diff --git a/libraries/RC_Channel/RC_Channel_aux.h b/libraries/RC_Channel/RC_Channel_aux.h
index c335db7404..aa086b36d4 100644
--- a/libraries/RC_Channel/RC_Channel_aux.h
+++ b/libraries/RC_Channel/RC_Channel_aux.h
@@ -165,11 +165,17 @@ public:
 
     // find first channel that a function is assigned to
     static bool find_channel(Aux_servo_function_t function, uint8_t &chan);
+
+    // control pass-thru of channels
+    static void disable_passthrough(bool disable) {
+        _disable_passthrough = disable;
+    }
     
 private:
     static uint64_t _function_mask[2];
     static bool _initialised;
     static RC_Channel_aux *_aux_channels[RC_AUX_MAX_CHANNELS];
+    static bool _disable_passthrough;
 
     void aux_servo_function_setup(void);
     static void set_function_mask(uint8_t function);