diff --git a/ArduPlane/GCS_Mavlink.cpp b/ArduPlane/GCS_Mavlink.cpp
index 45a596bc6331a8..849ef79910aa78 100644
--- a/ArduPlane/GCS_Mavlink.cpp
+++ b/ArduPlane/GCS_Mavlink.cpp
@@ -1382,22 +1382,20 @@ void GCS_MAVLINK_Plane::handle_set_position_target_global_int(const mavlink_mess
         
         if (pos_target.type_mask & alt_mask)
         {
-            cmd.content.location.alt = pos_target.alt * 100;
-            cmd.content.location.relative_alt = false;
-            cmd.content.location.terrain_alt = false;
+            const int32_t alt_cm = pos_target.alt * 100;
             switch (pos_target.coordinate_frame) 
             {
                 case MAV_FRAME_GLOBAL:
                 case MAV_FRAME_GLOBAL_INT:
+                    cmd.content.location.set_alt_cm(alt_cm, Location::AltFrame::ABSOLUTE);
                     break; //default to MSL altitude
                 case MAV_FRAME_GLOBAL_RELATIVE_ALT:
                 case MAV_FRAME_GLOBAL_RELATIVE_ALT_INT:
-                    cmd.content.location.relative_alt = true;
+                    cmd.content.location.set_alt_cm(alt_cm, Location::AltFrame::ABOVE_HOME);
                     break;
                 case MAV_FRAME_GLOBAL_TERRAIN_ALT:
                 case MAV_FRAME_GLOBAL_TERRAIN_ALT_INT:
-                    cmd.content.location.relative_alt = true;
-                    cmd.content.location.terrain_alt = true;
+                    cmd.content.location.set_alt_cm(alt_cm, Location::AltFrame::ABOVE_TERRAIN);
                     break;
                 default:
                     gcs().send_text(MAV_SEVERITY_WARNING, "Invalid coord frame in SET_POSTION_TARGET_GLOBAL_INT");