diff --git a/libraries/AC_Avoidance/AC_Avoid.cpp b/libraries/AC_Avoidance/AC_Avoid.cpp
index 3e13d70dba..1b10982a69 100644
--- a/libraries/AC_Avoidance/AC_Avoid.cpp
+++ b/libraries/AC_Avoidance/AC_Avoid.cpp
@@ -414,7 +414,7 @@ float AC_Avoid::get_max_speed(float kP, float accel_cmss, float distance_cm, flo
     if (is_zero(kP)) {
         return safe_sqrt(2.0f * distance_cm * accel_cmss);
     } else {
-        return AC_AttitudeControl::sqrt_controller(distance_cm, kP, accel_cmss, dt);
+        return sqrt_controller(distance_cm, kP, accel_cmss, dt);
     }
 }