diff --git a/libraries/AP_HAL_AVR_SITL/sitl_ins.cpp b/libraries/AP_HAL_AVR_SITL/sitl_ins.cpp
index f6c376a6ef..5d4b09eb58 100644
--- a/libraries/AP_HAL_AVR_SITL/sitl_ins.cpp
+++ b/libraries/AP_HAL_AVR_SITL/sitl_ins.cpp
@@ -111,6 +111,12 @@ void SITL_State::_update_ins(float roll, 	float pitch, 	float yaw,		// Relative
 	yAccel += accel_noise * _rand_float();
 	zAccel += accel_noise * _rand_float();
 
+        if (fabs(_sitl->accel_fail) > 1.0e-6) {
+            xAccel = _sitl->accel_fail;
+            yAccel = _sitl->accel_fail;
+            zAccel = _sitl->accel_fail;
+        }
+
 	p += gyro_noise * _rand_float();
 	q += gyro_noise * _rand_float();
 	r += gyro_noise * _rand_float();
diff --git a/libraries/SITL/SITL.cpp b/libraries/SITL/SITL.cpp
index 03cb7bbf7a..ace38d5cb9 100644
--- a/libraries/SITL/SITL.cpp
+++ b/libraries/SITL/SITL.cpp
@@ -46,6 +46,7 @@ const AP_Param::GroupInfo SITL::var_info[] PROGMEM = {
     AP_GROUPINFO("GPS_HZ",        18, SITL,  gps_hertz,  5),
     AP_GROUPINFO("BATT_VOLTAGE",  19, SITL,  batt_voltage,  12.6),
     AP_GROUPINFO("ASPD_RND",      20, SITL,  aspd_noise,  0.5),
+    AP_GROUPINFO("ACCEL_FAIL",    21, SITL,  accel_fail,  0),
     AP_GROUPEND
 };
 
diff --git a/libraries/SITL/SITL.h b/libraries/SITL/SITL.h
index 8054a0491f..fc9845bbe1 100644
--- a/libraries/SITL/SITL.h
+++ b/libraries/SITL/SITL.h
@@ -65,6 +65,7 @@ public:
     AP_Vector3f  gps_glitch;  // glitch offsets in lat, lon and altitude
     AP_Int8  gps_hertz;   // GPS update rate in Hz
     AP_Float batt_voltage; // battery voltage base
+    AP_Float accel_fail;  // accelerometer failure value
 
     // wind control
     AP_Float wind_speed;