diff --git a/src/FDM/YASim/proptest.cpp b/src/FDM/YASim/proptest.cpp
index 49abc1916..c0482b8fb 100644
--- a/src/FDM/YASim/proptest.cpp
+++ b/src/FDM/YASim/proptest.cpp
@@ -11,6 +11,8 @@
 #include "Propeller.hpp"
 #include "Atmosphere.hpp"
 
+#include <simgear/misc/sg_path.hxx>
+
 using namespace yasim;
 
 // Usage: proptest plane.xml [alt-ft] [spd-ktas]
diff --git a/src/FDM/YASim/yasim-test.cpp b/src/FDM/YASim/yasim-test.cpp
index dbd860887..61ed2a3dd 100644
--- a/src/FDM/YASim/yasim-test.cpp
+++ b/src/FDM/YASim/yasim-test.cpp
@@ -5,6 +5,7 @@
 
 #include <simgear/props/props.hxx>
 #include <simgear/xml/easyxml.hxx>
+#include <simgear/misc/sg_path.hxx>
 
 #include "FGFDM.hpp"
 #include "Atmosphere.hpp"