diff --git a/ArduPlane/Parameters.cpp b/ArduPlane/Parameters.cpp
index b2db9099f8..5f746640e1 100644
--- a/ArduPlane/Parameters.cpp
+++ b/ArduPlane/Parameters.cpp
@@ -60,7 +60,7 @@ const AP_Param::Info Plane::var_info[] = {
     // @DisplayName: GCS PID tuning mask
     // @Description: bitmask of PIDs to send MAVLink PID_TUNING messages for
     // @User: Advanced
-    // @Bitmask: 0:Roll,1:Pitch,2:Yaw,3:Steering,4:Landing
+    // @Bitmask: 0:Roll,1:Pitch,2:Yaw,3:Steering,4:Landing,5:AccZ
     GSCALAR(gcs_pid_mask,           "GCS_PID_MASK",     0),
 
     // @Param: KFF_RDDRMIX