diff --git a/src/FDM/JSBSim/models/flight_control/FGGradient.cpp b/src/FDM/JSBSim/models/flight_control/FGGradient.cpp
deleted file mode 100644
index 9046e4975..000000000
--- a/src/FDM/JSBSim/models/flight_control/FGGradient.cpp
+++ /dev/null
@@ -1,121 +0,0 @@
-/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
- Module:       FGGradient.cpp
- Author:
- Date started:
-
- ------------- Copyright (C) 2000 -------------
-
- This program is free software; you can redistribute it and/or modify it under
- the terms of the GNU Lesser General Public License as published by the Free Software
- Foundation; either version 2 of the License, or (at your option) any later
- version.
-
- This program is distributed in the hope that it will be useful, but WITHOUT
- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
- details.
-
- You should have received a copy of the GNU Lesser General Public License along with
- this program; if not, write to the Free Software Foundation, Inc., 59 Temple
- Place - Suite 330, Boston, MA  02111-1307, USA.
-
- Further information about the GNU Lesser General Public License can also be found on
- the world wide web at http://www.gnu.org.
-
-FUNCTIONAL DESCRIPTION
---------------------------------------------------------------------------------
-
-HISTORY
---------------------------------------------------------------------------------
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-COMMENTS, REFERENCES,  and NOTES
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-INCLUDES
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-
-#include "FGGradient.h"
-#include <iostream>
-
-using namespace std;
-
-namespace JSBSim {
-
-static const char *IdSrc = "$Id: FGGradient.cpp,v 1.4 2009/10/24 22:59:30 jberndt Exp $";
-static const char *IdHdr = ID_GRADIENT;
-
-/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-CLASS IMPLEMENTATION
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-
-
-FGGradient::FGGradient(FGFCS* fcs, Element* element) : FGFCSComponent(fcs, element)
-{
-  FGFCSComponent::bind();
-
-  Debug(0);
-}
-
-//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-FGGradient::~FGGradient()
-{
-  Debug(1);
-}
-
-//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-bool FGGradient::Run(void )
-{
-  return true;
-}
-
-//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-//    The bitmasked value choices are as follows:
-//    unset: In this case (the default) JSBSim would only print
-//       out the normally expected messages, essentially echoing
-//       the config files as they are read. If the environment
-//       variable is not set, debug_lvl is set to 1 internally
-//    0: This requests JSBSim not to output any messages
-//       whatsoever.
-//    1: This value explicity requests the normal JSBSim
-//       startup messages
-//    2: This value asks for a message to be printed out when
-//       a class is instantiated
-//    4: When this value is set, a message is displayed when a
-//       FGModel object executes its Run() method
-//    8: When this value is set, various runtime state variables
-//       are printed out periodically
-//    16: When set various parameters are sanity checked and
-//       a message is printed out when they go out of bounds
-
-void FGGradient::Debug(int from)
-{
-  if (debug_lvl <= 0) return;
-
-  if (debug_lvl & 1) { // Standard console startup message output
-    if (from == 0) { // Constructor
-
-    }
-  }
-  if (debug_lvl & 2 ) { // Instantiation/Destruction notification
-    if (from == 0) cout << "Instantiated: FGGradient" << endl;
-    if (from == 1) cout << "Destroyed:    FGGradient" << endl;
-  }
-  if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
-  }
-  if (debug_lvl & 8 ) { // Runtime state variables
-  }
-  if (debug_lvl & 16) { // Sanity checking
-  }
-  if (debug_lvl & 64) {
-    if (from == 0) { // Constructor
-      cout << IdSrc << endl;
-      cout << IdHdr << endl;
-    }
-  }
-}
-}
diff --git a/src/FDM/JSBSim/models/flight_control/FGGradient.h b/src/FDM/JSBSim/models/flight_control/FGGradient.h
deleted file mode 100644
index 06d3e843f..000000000
--- a/src/FDM/JSBSim/models/flight_control/FGGradient.h
+++ /dev/null
@@ -1,80 +0,0 @@
-/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
- Header:       FGGradient.h
- Author:       
- Date started: 
-
- ------------- Copyright (C)  -------------
-
- This program is free software; you can redistribute it and/or modify it under
- the terms of the GNU Lesser General Public License as published by the Free Software
- Foundation; either version 2 of the License, or (at your option) any later
- version.
-
- This program is distributed in the hope that it will be useful, but WITHOUT
- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
- details.
-
- You should have received a copy of the GNU Lesser General Public License along with
- this program; if not, write to the Free Software Foundation, Inc., 59 Temple
- Place - Suite 330, Boston, MA  02111-1307, USA.
-
- Further information about the GNU Lesser General Public License can also be found on
- the world wide web at http://www.gnu.org.
-
-HISTORY
---------------------------------------------------------------------------------
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-SENTRY
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-
-#ifndef FGGRADIENT_H
-#define FGGRADIENT_H
-
-/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-INCLUDES
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-
-#include "FGFCSComponent.h"
-#include "input_output/FGXMLElement.h"
-
-/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-DEFINITIONS
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-
-#define ID_GRADIENT "$Id: FGGradient.h,v 1.5 2009/10/02 10:30:09 jberndt Exp $"
-
-/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-FORWARD DECLARATIONS
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-
-namespace JSBSim {
-
-class FGFCS;
-
-/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-CLASS DOCUMENTATION
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-
-/** Encapsulates a gradient component for the flight control system.
-  */
-
-/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-CLASS DECLARATION
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-
-class FGGradient  : public FGFCSComponent
-{
-public:
-  FGGradient(FGFCS* fcs, Element* element);
-  ~FGGradient();
-
-  bool Run (void);
-
-private:
-  void Debug(int from);
-};
-}
-#endif