diff --git a/libraries/AP_Math/vector3.h b/libraries/AP_Math/vector3.h
index 35c375917a..adf33847bf 100644
--- a/libraries/AP_Math/vector3.h
+++ b/libraries/AP_Math/vector3.h
@@ -51,7 +51,7 @@ public:
 	T x, y, z;
 
 	// trivial ctor
-	Vector3<T>() { x = y = x = 0; }
+	Vector3<T>() { x = y = z = 0; }
 
 	// setting ctor
 	Vector3<T>(const T x0, const T y0, const T z0): x(x0), y(y0), z(z0) {}