diff --git a/ArduPlane/GCS_Mavlink.pde b/ArduPlane/GCS_Mavlink.pde
index dcbd6a26153bd4a9bf4eba9e6add402fa1061689..df31a18511bd46725c00cda61d92750a7aeb1962 100644
--- a/ArduPlane/GCS_Mavlink.pde
+++ b/ArduPlane/GCS_Mavlink.pde
@@ -142,7 +142,7 @@ static NOINLINE void send_extended_status1(mavlink_channel_t chan, uint16_t pack
         control_sensors_present |= (1<<2); // compass present
     }
     control_sensors_present |= (1<<3); // absolute pressure sensor present
-    if (g_gps->fix) {
+    if (g_gps != NULL && g_gps->fix) {
         control_sensors_present |= (1<<5); // GPS present
     }
     control_sensors_present |= (1<<10); // 3D angular rate control