diff --git a/src/modules/mavlink/mavlink_main.cpp b/src/modules/mavlink/mavlink_main.cpp
index e8be7cc5e99..4f4ee4f0b57 100644
--- a/src/modules/mavlink/mavlink_main.cpp
+++ b/src/modules/mavlink/mavlink_main.cpp
@@ -119,6 +119,7 @@ static void usage(void);
 bool Mavlink::_boot_complete = false;
 
 Mavlink::Mavlink() :
+	_device_name("/dev/ttyS1"),
 	_task_should_exit(false),
 	next(nullptr),
 	_instance_id(0),