diff --git a/EKF/control.cpp b/EKF/control.cpp
index 75d6dd92fb..3cc36474cb 100644
--- a/EKF/control.cpp
+++ b/EKF/control.cpp
@@ -379,6 +379,10 @@ void Ekf::controlOpticalFlowFusion()
 			}
 		}
 
+		// Accumulate autopilot gyro data across the same time interval as the flow sensor
+		_imu_del_ang_of += _imu_sample_delayed.delta_ang - _state.gyro_bias;
+		_delta_time_of += _imu_sample_delayed.delta_ang_dt;
+
 		// fuse the data
 		if (_control_status.flags.opt_flow) {
 			// Update optical flow bias estimates
diff --git a/EKF/optflow_fusion.cpp b/EKF/optflow_fusion.cpp
index 29ff1531fb..df0dd3163d 100644
--- a/EKF/optflow_fusion.cpp
+++ b/EKF/optflow_fusion.cpp
@@ -524,20 +524,16 @@ void Ekf::get_drag_innov_var(float drag_innov_var[2])
 // calculate optical flow gyro bias errors
 void Ekf::calcOptFlowBias()
 {
-	// accumulate the bias corrected delta angles from the navigation sensor and lapsed time
-	_imu_del_ang_of += _imu_sample_delayed.delta_ang;
-	_delta_time_of += _imu_sample_delayed.delta_ang_dt;
-
 	// reset the accumulators if the time interval is too large
 	if (_delta_time_of > 1.0f) {
 		_imu_del_ang_of.setZero();
 		_delta_time_of = 0.0f;
+		return;
 	}
 
 	// if accumulation time differences are not excessive and accumulation time is adequate
 	// compare the optical flow and and navigation rate data and calculate a bias error
-	if ((fabsf(_delta_time_of - _flow_sample_delayed.dt) < 0.05f) && (_delta_time_of > 0.01f)
-	    && (_flow_sample_delayed.dt > 0.01f)) {
+	if ((fabsf(_delta_time_of - _flow_sample_delayed.dt) < 0.1f) && (_delta_time_of > 0.01f)) {
 		// calculate a reference angular rate
 		Vector3f reference_body_rate;
 		reference_body_rate = _imu_del_ang_of * (1.0f / _delta_time_of);