diff --git a/sw/airborne/downlink.h b/sw/airborne/downlink.h
index d76f2f1b49..0c838b12d7 100644
--- a/sw/airborne/downlink.h
+++ b/sw/airborne/downlink.h
@@ -33,6 +33,7 @@
 #include <inttypes.h>
 
 #include "messages.h"
+#include "airframe.h" // AC_ID is required
 
 #if defined SITL