diff --git a/src/modules/fw_att_control/fw_att_control_params.c b/src/modules/fw_att_control/fw_att_control_params.c
index 6b248cbe2e..6ce6cef4eb 100644
--- a/src/modules/fw_att_control/fw_att_control_params.c
+++ b/src/modules/fw_att_control/fw_att_control_params.c
@@ -136,6 +136,7 @@ PARAM_DEFINE_FLOAT(FW_PR_IMAX, 0.2f);
  * @max 2.0
  * @group FW Attitude Control
  */
+//xxx: set to 0 as default, see comment on turn_offset in ECL_PitchController::control_attitude(...)
 PARAM_DEFINE_FLOAT(FW_P_ROLLFF, 0.0f);
 
 /**