diff --git a/ArduCopter/ArduCopter.pde b/ArduCopter/ArduCopter.pde
index b9da3535b1..5b27ee139b 100644
--- a/ArduCopter/ArduCopter.pde
+++ b/ArduCopter/ArduCopter.pde
@@ -109,7 +109,6 @@
 #include <AP_Mount.h>           // Camera/Antenna mount
 #include <AP_Airspeed.h>        // needed for AHRS build
 #include <AP_InertialNav.h>     // ArduPilot Mega inertial navigation library
-#include <ThirdOrderCompFilter.h>   // Complementary filter for combining barometer altitude with accelerometers
 #include <DigitalWriteFast.h>   // faster digital write for LEDs
 #include <memcheck.h>