diff --git a/src/blackmisc/aviation/altitude.h b/src/blackmisc/aviation/altitude.h
index 4d5831a6d..62223ea6a 100644
--- a/src/blackmisc/aviation/altitude.h
+++ b/src/blackmisc/aviation/altitude.h
@@ -50,7 +50,7 @@ namespace BlackMisc
 
         protected:
             //! \copydoc CValueObject::convertToQString
-            virtual QString convertToQString(bool i18n) const override;
+            virtual QString convertToQString(bool i18n = false) const override;
 
         public:
             //! Default constructor: 0 Altitude true