diff --git a/libraries/AP_AccelCal/AP_AccelCal.cpp b/libraries/AP_AccelCal/AP_AccelCal.cpp
index 0867cfbf92..8cf1fc126a 100644
--- a/libraries/AP_AccelCal/AP_AccelCal.cpp
+++ b/libraries/AP_AccelCal/AP_AccelCal.cpp
@@ -12,12 +12,13 @@
 */
 
 #include "AP_AccelCal.h"
-#include <stdarg.h>
-#include <GCS_MAVLink/GCS.h>
-#include <GCS_MAVLink/GCS_MAVLink.h>
-#include <AP_HAL/AP_HAL.h>
 
 #if HAL_INS_ACCELCAL_ENABLED
+
+#include <stdarg.h>
+#include <AP_HAL/AP_HAL.h>
+#include <GCS_MAVLink/GCS.h>
+
 #define AP_ACCELCAL_POSITION_REQUEST_INTERVAL_MS 1000
 
 #define _printf(fmt, args ...) do {                                     \
diff --git a/libraries/AP_AccelCal/AP_AccelCal.h b/libraries/AP_AccelCal/AP_AccelCal.h
index 5b0e26d082..af899a6e44 100644
--- a/libraries/AP_AccelCal/AP_AccelCal.h
+++ b/libraries/AP_AccelCal/AP_AccelCal.h
@@ -1,8 +1,7 @@
 #pragma once
 
-#include <GCS_MAVLink/GCS.h>
-#include "AccelCalibrator.h"
-#include "AP_Vehicle/AP_Vehicle_Type.h"
+#include <AP_HAL/AP_HAL_Boards.h>
+#include <GCS_MAVLink/GCS_config.h>
 
 #ifndef HAL_INS_ACCELCAL_ENABLED
 #if HAL_GCS_ENABLED
@@ -12,6 +11,10 @@
 #endif
 #endif
 
+#include <GCS_MAVLink/GCS_MAVLink.h>
+#include "AccelCalibrator.h"
+#include "AP_Vehicle/AP_Vehicle_Type.h"
+
 #define AP_ACCELCAL_MAX_NUM_CLIENTS 4
 class GCS_MAVLINK;
 class AP_AccelCal_Client;
@@ -50,7 +53,7 @@ public:
     bool running(void) const;
 
 private:
-    GCS_MAVLINK *_gcs;
+    class GCS_MAVLINK *_gcs;
     bool _use_gcs_snoop;
     bool _waiting_for_mavlink_ack = false;
     uint32_t _last_position_request_ms;