diff --git a/libraries/AP_Mission/examples/AP_Mission_test/AP_Mission_test.pde b/libraries/AP_Mission/examples/AP_Mission_test/AP_Mission_test.pde
index fb9237bd32..363e59a586 100644
--- a/libraries/AP_Mission/examples/AP_Mission_test/AP_Mission_test.pde
+++ b/libraries/AP_Mission/examples/AP_Mission_test/AP_Mission_test.pde
@@ -15,6 +15,7 @@
 #include <AP_Vehicle.h>
 #include <DataFlash.h>
 #include <AP_Mission.h>
+#include <AP_Terrain.h>
 #include <AP_GPS.h>             // ArduPilot GPS library
 #include <AP_GPS_Glitch.h>      // GPS glitch protection library
 #include <AP_ADC.h>             // ArduPilot Mega Analog to Digital Converter Library