diff --git a/src/blackmisc/aviation/transponder.cpp b/src/blackmisc/aviation/transponder.cpp
index 3399763bc..5513691bd 100644
--- a/src/blackmisc/aviation/transponder.cpp
+++ b/src/blackmisc/aviation/transponder.cpp
@@ -22,6 +22,7 @@ namespace BlackMisc
         {
             CValueObject<CTransponder>::registerMetadata();
             qRegisterMetaType<TransponderMode>();
+            qDBusRegisterMetaType<CTransponder::TransponderMode>();
         }
 
         CTransponder::CTransponder(int transponderCode, CTransponder::TransponderMode transponderMode) :