diff --git a/libraries/AC_AttitudeControl/AC_AttitudeControl.h b/libraries/AC_AttitudeControl/AC_AttitudeControl.h
index ea51fd312a..6f46617417 100644
--- a/libraries/AC_AttitudeControl/AC_AttitudeControl.h
+++ b/libraries/AC_AttitudeControl/AC_AttitudeControl.h
@@ -470,7 +470,7 @@ protected:
 
 public:
     // log a CTRL message
-    void control_monitor_log(void);
+    void control_monitor_log(void) const;
 
     // return current RMS controller filter for each axis
     float control_monitor_rms_output_roll(void) const;
diff --git a/libraries/AC_AttitudeControl/ControlMonitor.cpp b/libraries/AC_AttitudeControl/ControlMonitor.cpp
index c58348dd61..97e48c102b 100644
--- a/libraries/AC_AttitudeControl/ControlMonitor.cpp
+++ b/libraries/AC_AttitudeControl/ControlMonitor.cpp
@@ -39,7 +39,7 @@ void AC_AttitudeControl::control_monitor_update(void)
 /*
   log a CRTL message
  */
-void AC_AttitudeControl::control_monitor_log(void)
+void AC_AttitudeControl::control_monitor_log(void) const
 {
 // @LoggerMessage: CTRL
 // @Description: Attitude Control oscillation monitor diagnostics