diff --git a/libraries/AP_AHRS/AP_AHRS.cpp b/libraries/AP_AHRS/AP_AHRS.cpp
index ab414a545e..4bfb122993 100644
--- a/libraries/AP_AHRS/AP_AHRS.cpp
+++ b/libraries/AP_AHRS/AP_AHRS.cpp
@@ -580,7 +580,7 @@ void AP_AHRS::update_EKF3(void)
             // update _accel_ef_ekf
             for (uint8_t i=0; i<_ins.get_accel_count(); i++) {
                 Vector3f accel = _ins.get_accel(i);
-                if (i==_ins.get_primary_accel()) {
+                if (i == primary_imu) {
                     accel -= abias;
                 }
                 if (_ins.get_accel_health(i)) {