diff --git a/EKF/mag_fusion.cpp b/EKF/mag_fusion.cpp
index c31ad0cf58..857d1c019c 100644
--- a/EKF/mag_fusion.cpp
+++ b/EKF/mag_fusion.cpp
@@ -610,9 +610,11 @@ void Ekf::fuseHeading()
 
 	// TODO - enable use of an off-board heading measurement
 
-	// rotate the magnetometer measurement into earth frame using an assumed zero yaw angle
+	// rotate the magnetometer measurement into earth frame
 	matrix::Euler<float> euler(_state.quat_nominal);
 	float predicted_hdg = euler(2); // we will need the predicted heading to calculate the innovation
+
+	// Set the yaw angle to zero and rotate the measurements into earth frame using the zero yaw angle
 	euler(2) = 0.0f;
 	matrix::Dcm<float> R_to_earth(euler);
 	matrix::Vector3f mag_earth_pred = R_to_earth * _mag_sample_delayed.mag;