diff --git a/ArduCopter/GCS_Mavlink.cpp b/ArduCopter/GCS_Mavlink.cpp
index a20beb419c..e6c12cc7cf 100644
--- a/ArduCopter/GCS_Mavlink.cpp
+++ b/ArduCopter/GCS_Mavlink.cpp
@@ -577,6 +577,7 @@ bool GCS_MAVLINK_Copter::handle_guided_request(AP_Mission::Mission_Command &cmd)
 void GCS_MAVLINK_Copter::packetReceived(const mavlink_status_t &status,
                                         const mavlink_message_t &msg)
 {
+    // we handle these messages here to avoid them being blocked by mavlink routing code
 #if HAL_ADSB_ENABLED
     if (copter.g2.dev_options.get() & DevOptionADSBMAVLink) {
         // optional handling of GLOBAL_POSITION_INT as a MAVLink based avoidance source