diff --git a/ArduCopter/Parameters.cpp b/ArduCopter/Parameters.cpp
index a190ce8a04..81b8c7688f 100644
--- a/ArduCopter/Parameters.cpp
+++ b/ArduCopter/Parameters.cpp
@@ -802,6 +802,13 @@ const AP_Param::Info Copter::var_info[] PROGMEM = {
     // @Description: Throttle acceleration controller D gain.  Compensates for short-term change in desired vertical acceleration vs actual acceleration
     // @Range: 0.000 0.400
     // @User: Standard
+
+    // @Param: ACCEL_Z_FILT_HZ
+    // @DisplayName: Throttle acceleration filter
+    // @Description: Filter applied to acceleration to reduce noise.  Lower values reduce noise but add delay.
+    // @Range: 1.000 100.000
+    // @Units: Hz
+    // @User: Standard
     GGROUP(pid_accel_z, "ACCEL_Z_", AC_PID),
 
     // P controllers
@@ -886,8 +893,6 @@ const AP_Param::Info Copter::var_info[] PROGMEM = {
     GOBJECT(circle_nav, "CIRCLE_",  AC_Circle),
 
 #if FRAME_CONFIG == HELI_FRAME
-    // @Group: ATC_
-    // @Path: ../libraries/AC_AttitudeControl/AC_AttitudeControl_Heli.cpp
     GOBJECT(attitude_control, "ATC_", AC_AttitudeControl_Heli),
 #else
     // @Group: ATC_
@@ -929,7 +934,7 @@ const AP_Param::Info Copter::var_info[] PROGMEM = {
     GOBJECT(camera_mount,           "MNT",  AP_Mount),
 #endif
 
-    // @Group: BATT_
+    // @Group: BATT
     // @Path: ../libraries/AP_BattMonitor/AP_BattMonitor.cpp
     GOBJECT(battery,                "BATT",         AP_BattMonitor),
 
@@ -1012,7 +1017,7 @@ const AP_Param::Info Copter::var_info[] PROGMEM = {
 
 #else
     // @Group: MOT_
-    // @Path: ../libraries/AP_Motors/AP_Motors_Class.cpp
+    // @Path: ../libraries/AP_Motors/AP_MotorsMulticopter.cpp
     GOBJECT(motors, "MOT_",         AP_MotorsMulticopter),
 #endif