diff --git a/matrix/Euler.hpp b/matrix/Euler.hpp
index c055b0d827..346acf2c51 100644
--- a/matrix/Euler.hpp
+++ b/matrix/Euler.hpp
@@ -54,7 +54,7 @@ public:
             phi() = (Type)0.0;
             psi() = (Type)atan2(dcm(1,2) - dcm(0,1), dcm(0,2) + dcm(1,1)) + theta();
 
-        } else if (fabs(theta() + (Type)M_PI_2) < (Type)1.0e-3) {
+        } else if ((Type)fabs(theta() + (Type)M_PI_2) < (Type)1.0e-3) {
             phi() = (Type)0.0;
             psi() = (Type)atan2(dcm(1,2) - dcm(0,1), dcm(0,2) + dcm(1,1)) - theta();