diff --git a/libraries/AP_ExternalAHRS/AP_ExternalAHRS.h b/libraries/AP_ExternalAHRS/AP_ExternalAHRS.h
index 22ef0e9d5f829..2868c9cedee8a 100644
--- a/libraries/AP_ExternalAHRS/AP_ExternalAHRS.h
+++ b/libraries/AP_ExternalAHRS/AP_ExternalAHRS.h
@@ -137,7 +137,7 @@ class AP_ExternalAHRS {
     } mag_data_message_t;
 
     typedef struct {
-        uint16_t gps_week;                   // GPS week, 0xFFFF if not available
+        uint16_t gps_week;
         uint32_t ms_tow;
         uint8_t  fix_type;
         uint8_t  satellites_in_view;