diff --git a/ArduPlane/system.pde b/ArduPlane/system.pde
index 26b7b92fb7..e11f895074 100644
--- a/ArduPlane/system.pde
+++ b/ArduPlane/system.pde
@@ -458,6 +458,7 @@ static void startup_IMU_ground(void)
 	imu.init(IMU::COLD_START, mavlink_delay, flash_leds, &timer_scheduler);
 	imu.init_accel(mavlink_delay, flash_leds);
 	dcm.set_centripetal(1);
+    dcm.matrix_reset();
 
 	// read Baro pressure at ground
 	//-----------------------------
diff --git a/ArduPlane/test.pde b/ArduPlane/test.pde
index 5e34820376..a085304733 100644
--- a/ArduPlane/test.pde
+++ b/ArduPlane/test.pde
@@ -502,6 +502,7 @@ test_imu(uint8_t argc, const Menu::arg *argv)
 {
 	//Serial.printf_P(PSTR("Calibrating."));
 	imu.init(IMU::COLD_START, delay, flash_leds, &timer_scheduler);
+    dcm.matrix_reset();
 
 	print_hit_enter();
 	delay(1000);
@@ -563,6 +564,7 @@ test_mag(uint8_t argc, const Menu::arg *argv)
 
     // we need the DCM initialised for this test
 	imu.init(IMU::COLD_START, delay, flash_leds, &timer_scheduler);
+    dcm.matrix_reset();
 
 	int counter = 0;
 		//Serial.printf_P(PSTR("MAG_ORIENTATION: %d\n"), MAG_ORIENTATION);