diff --git a/sw/airborne/firmwares/fixedwing/main_ap.c b/sw/airborne/firmwares/fixedwing/main_ap.c
index ca2fcbca1b..c76f12b1d5 100644
--- a/sw/airborne/firmwares/fixedwing/main_ap.c
+++ b/sw/airborne/firmwares/fixedwing/main_ap.c
@@ -93,8 +93,6 @@ static inline void on_gyro_event( void );
 static inline void on_accel_event( void );
 static inline void on_mag_event( void );
 volatile uint8_t ahrs_timeout_counter = 0;
-#else
-static inline void on_ahrs_event(void);
 #endif // USE_IMU
 #endif // USE_AHRS
 
@@ -587,13 +585,9 @@ void event_task_ap( void ) {
   i2c_event();
 #endif
 
-#if USE_AHRS
-#if USE_IMU
+#if USE_AHRS && USE_IMU
   ImuEvent(on_gyro_event, on_accel_event, on_mag_event);
-#else
-  AhrsEvent(on_ahrs_event);
-#endif // USE_IMU
-#endif // USE_AHRS
+#endif
 
 #if USE_GPS
   GpsEvent(on_gps_solution);
@@ -725,13 +719,6 @@ static inline void on_mag_event(void)
 #endif
 }
 
-#else // USE_IMU not defined
-static inline void on_ahrs_event(void)
-{
-#ifdef AHRS_UPDATE_FW_ESTIMATOR
-  ahrs_update_fw_estimator();
-#endif
-}
 #endif // USE_IMU
 
 #endif // USE_AHRS
diff --git a/sw/airborne/subsystems/ahrs/ahrs_infrared.h b/sw/airborne/subsystems/ahrs/ahrs_infrared.h
index 43a2b3b340..a4d2870756 100644
--- a/sw/airborne/subsystems/ahrs/ahrs_infrared.h
+++ b/sw/airborne/subsystems/ahrs/ahrs_infrared.h
@@ -36,7 +36,4 @@ extern void ahrs_update_infrared(void);
 // TODO copy ahrs to state instead of estimator
 extern void ahrs_update_fw_estimator(void);
 
-#define AhrsEvent(_available_callback) {        \
-  }
-
 #endif /* AHRS_INFRARED_H */
diff --git a/sw/airborne/subsystems/ahrs/ahrs_sim.c b/sw/airborne/subsystems/ahrs/ahrs_sim.c
index 290602091b..3dcfcf0263 100644
--- a/sw/airborne/subsystems/ahrs/ahrs_sim.c
+++ b/sw/airborne/subsystems/ahrs/ahrs_sim.c
@@ -53,6 +53,10 @@ void update_ahrs_from_sim(void) {
   FLOAT_RMAT_OF_EULERS(ahrs_float.ltp_to_imu_rmat, ahrs_float.ltp_to_imu_euler);
 
   compute_body_orientation_and_rates();
+
+#ifdef AHRS_UPDATE_FW_ESTIMATOR
+  ahrs_update_fw_estimator();
+#endif
 }
 
 
@@ -92,6 +96,10 @@ void ahrs_align(void)
 
 
 void ahrs_propagate(void) {
+  if (ahrs_sim_available) {
+    update_ahrs_from_sim();
+    ahrs_sim_available = FALSE;
+  }
 }
 
 void ahrs_update_accel(void) {
diff --git a/sw/airborne/subsystems/ahrs/ahrs_sim.h b/sw/airborne/subsystems/ahrs/ahrs_sim.h
index 7aca2313a7..ee36d402be 100644
--- a/sw/airborne/subsystems/ahrs/ahrs_sim.h
+++ b/sw/airborne/subsystems/ahrs/ahrs_sim.h
@@ -37,14 +37,4 @@ extern float ins_pitch_neutral;
 
 extern void update_ahrs_from_sim(void);
 
-#define AhrsEvent(_available_callback) {        \
-    if (ahrs_sim_available) {                   \
-      update_ahrs_from_sim();               \
-      _available_callback();                    \
-      ahrs_sim_available = FALSE;               \
-    }                                           \
-  }
-
-
-
 #endif /* AHRS_SIM_H */