diff --git a/ArduCopter/sensors.pde b/ArduCopter/sensors.pde
index 9fa33a5252..21692965bd 100644
--- a/ArduCopter/sensors.pde
+++ b/ArduCopter/sensors.pde
@@ -81,6 +81,7 @@ static void init_compass()
 	dcm.set_compass(&compass);
 	compass.init();
 	compass.get_offsets();					// load offsets to account for airframe magnetic interference
+	compass.null_offsets_enable();
 }
 
 static void init_optflow()
diff --git a/ArduPlane/system.pde b/ArduPlane/system.pde
index 5b802942d6..7cced3635c 100644
--- a/ArduPlane/system.pde
+++ b/ArduPlane/system.pde
@@ -202,6 +202,7 @@ static void init_ardupilot()
         } else {
             dcm.set_compass(&compass);
             compass.get_offsets();						// load offsets to account for airframe magnetic interference
+            compass.null_offsets_enable();
         }
 	}
 #endif
diff --git a/ArduPlane/test.pde b/ArduPlane/test.pde
index f55604454e..ebe7d76091 100644
--- a/ArduPlane/test.pde
+++ b/ArduPlane/test.pde
@@ -586,6 +586,7 @@ test_mag(uint8_t argc, const Menu::arg *argv)
         Serial.println_P(PSTR("Compass initialisation failed!"));
         return 0;
     }
+    compass.null_offsets_enable();
     dcm.set_compass(&compass);
     report_compass();
 
diff --git a/libraries/AP_Compass/Compass.cpp b/libraries/AP_Compass/Compass.cpp
index d67c900ed0..4d5d69a9c4 100644
--- a/libraries/AP_Compass/Compass.cpp
+++ b/libraries/AP_Compass/Compass.cpp
@@ -11,6 +11,7 @@ Compass::Compass(AP_Var::Key key) :
     _offset				(&_group, 1),
     _declination		(&_group, 2, 0.0, PSTR("DEC")),
     _null_init_done(false),
+    _null_enable(false),
 	product_id(AP_COMPASS_TYPE_UNKNOWN)
 {
     // Default the orientation matrix to none - will be overridden at group load time
@@ -146,6 +147,8 @@ Compass::null_offsets(const Matrix3f &dcm_matrix)
     float       weight;
 
     Vector3f mag_body_new = Vector3f(mag_x,mag_y,mag_z);
+    
+    if(_null_enable == false) return;
 
     if(_null_init_done) {
         dcm_new_from_last = dcm_matrix.transposed() * _last_dcm_matrix;      // Note 11/20/2010: transpose() is not working, transposed() is.
@@ -166,3 +169,18 @@ Compass::null_offsets(const Matrix3f &dcm_matrix)
     _last_dcm_matrix = dcm_matrix;
 
 }
+
+
+void
+Compass::null_offsets_enable(void)
+{
+	_null_init_done = false;
+	_null_enable = true;
+}
+
+void
+Compass::null_offsets_disable(void)
+{
+	_null_init_done = false;
+	_null_enable = false;
+}
\ No newline at end of file
diff --git a/libraries/AP_Compass/Compass.h b/libraries/AP_Compass/Compass.h
index a2550f2518..33f5ccafbb 100644
--- a/libraries/AP_Compass/Compass.h
+++ b/libraries/AP_Compass/Compass.h
@@ -41,7 +41,7 @@ public:
 	float           heading_x;      ///< compass vector X magnitude
 	float           heading_y;      ///< compass vector Y magnitude
 	unsigned long   last_update;    ///< millis() time of last update
-	bool		healthy;        ///< true if last read OK
+	bool			healthy;        ///< true if last read OK
 
 	/// Constructor
 	///
@@ -117,6 +117,16 @@ public:
 	void null_offsets(const Matrix3f &dcm_matrix);
 
 
+	/// Enable/Start automatic offset updates 
+	///
+	void null_offsets_enable(void);
+
+
+	/// Disable/Stop automatic offset updates
+	///
+	void null_offsets_disable(void);
+
+
 	/// Sets the local magnetic field declination.
 	///
 	/// @param  radians             Local field declination.
@@ -130,6 +140,7 @@ protected:
 	AP_VarS<Vector3f>   _offset;
 	AP_Float            _declination;
 
+	bool                _null_enable;        	///< enabled flag for offset nulling
 	bool                _null_init_done;        ///< first-time-around flag used by offset nulling
 	Matrix3f            _last_dcm_matrix;       ///< previous DCM matrix used by offset nulling
 	Vector3f            _mag_body_last;         ///< ?? used by offset nulling
diff --git a/libraries/AP_DCM/AP_DCM.cpp b/libraries/AP_DCM/AP_DCM.cpp
index ceedb1055f..fd201551c4 100644
--- a/libraries/AP_DCM/AP_DCM.cpp
+++ b/libraries/AP_DCM/AP_DCM.cpp
@@ -195,6 +195,7 @@ AP_DCM::accel_adjust(void)
 void
 AP_DCM::matrix_reset(void)
 {
+	_compass->null_offsets_disable();		
 	_dcm_matrix.a.x = 1.0f;
 	_dcm_matrix.a.y = 0.0f;
 	_dcm_matrix.a.z = 0.0f;
@@ -207,6 +208,8 @@ AP_DCM::matrix_reset(void)
 	_omega_I.x = 0.0f;
 	_omega_I.y = 0.0f;
 	_omega_I.z = 0.0f;
+	_compass->null_offsets_enable();	// This call is needed to restart the nulling
+										// Otherwise the reset in the DCM matrix can mess up the nulling
 }
 
 /*************************************************