diff --git a/src/Instrumentation/encoder.cxx b/src/Instrumentation/encoder.cxx
deleted file mode 100644
index fa603f72f..000000000
--- a/src/Instrumentation/encoder.cxx
+++ /dev/null
@@ -1,112 +0,0 @@
-// encoder.cxx -- class to impliment an altitude encoder
-//
-// Written by Roy Vegard Ovesen, started September 2004.
-//
-// Copyright (C) 2004  Roy Vegard Ovesen - rvovesen@tiscali.no
-//
-// This program is free software; you can redistribute it and/or
-// modify it under the terms of the GNU 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
-// General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program; if not, write to the Free Software
-// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
-
-#ifdef HAVE_CONFIG_H
-#  include <config.h>
-#endif
-
-#include "encoder.hxx"
-
-
-// Altitude based on pressure difference from sea level.
-// pressure difference inHG, altitude ft
-static double altitude_data[][2] = {
- { -8.41, -8858.27 },
- { 0.00, 0.00 },
- { 3.05, 2952.76 },
- { 5.86, 5905.51 },
- { 8.41, 8858.27 },
- { 10.74, 11811.02 },
- { 12.87, 14763.78 },
- { 14.78, 17716.54 },
- { 16.55, 20669.29 },
- { 18.13, 23622.05 },
- { 19.62, 26574.80 },
- { 20.82, 29527.56 },
- { 21.96, 32480.31 },
- { 23.01, 35433.07 },
- { 23.91, 38385.83 },
- { 24.71, 41338.58 },
- { 25.40, 44291.34 },
- { 26.00, 47244.09 },
- { 26.51, 50196.85 },
- { 26.96, 53149.61 },
- { 27.35, 56102.36 },
- { 27.68, 59055.12 },
- { 27.98, 62007.87 },
- { 29.62, 100000.00 },            // just to fill it in
- { -1, -1 }
-};
-
-int round (double value, int nearest=1)
-{
-    return ((int) (value/nearest + 0.5)) * nearest;
-}
-
-
-Encoder::Encoder(SGPropertyNode *node)
-    :
-    _name(node->getStringValue("name", "encoder")),
-    _num(node->getIntValue("number", 0)),
-    _static_pressure(node->getStringValue("static-pressure", "/systems/static/pressure-inhg")),
-    altitudeTable(new SGInterpTable)
-{
-    int i;
-    for ( i = 0; altitude_data[i][0] != -1; i++ )
-        altitudeTable->addEntry(altitude_data[i][0], altitude_data[i][1]);
-}
-
-
-Encoder::~Encoder()
-{
-    delete altitudeTable;
-}
-
-
-void Encoder::init()
-{
-    string branch;
-    branch = "/instrumentation/" + _name;
-
-    SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
-    // Inputs
-    staticPressureNode = fgGetNode(_static_pressure.c_str(), true);
-    busPowerNode = fgGetNode("/systems/electrical/outputs/encoder", true);
-    serviceableNode = node->getChild("serviceable", 0, true);
-    // Outputs
-    pressureAltitudeNode = node->getChild("pressure-alt-ft", 0, true);
-    modeCAltitudeNode = node->getChild("mode-c-alt-ft", 0, true);
-}
-
-
-void Encoder::update(double dt)
-{
-    if (serviceableNode->getBoolValue())
-    {
-        double staticPressure = staticPressureNode->getDoubleValue();
-        double pressureAltitude =
-            altitudeTable->interpolate(29.92 - staticPressure);
-        int pressureAlt = round(pressureAltitude, 10);
-        int modeCAltitude = round(pressureAltitude, 100);
-
-        pressureAltitudeNode->setIntValue(pressureAlt);
-        modeCAltitudeNode->setIntValue(modeCAltitude);
-    }
-}
diff --git a/src/Instrumentation/encoder.hxx b/src/Instrumentation/encoder.hxx
deleted file mode 100644
index 755ebcdea..000000000
--- a/src/Instrumentation/encoder.hxx
+++ /dev/null
@@ -1,61 +0,0 @@
-// encoder.hxx -- class to impliment an altitude encoder
-//
-// Written by Roy Vegard Ovesen, started September 2004.
-//
-// Copyright (C) 2004  Roy Vegard Ovesen - rvovesen@tiscali.no
-//
-// This program is free software; you can redistribute it and/or
-// modify it under the terms of the GNU 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
-// General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program; if not, write to the Free Software
-// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
-
-#ifndef ENCODER_HXX
-#define ENCODER_HXX 1
-
-#ifndef __cplusplus
-# error This library requires C++
-#endif
-
-#include <Main/fg_props.hxx>
-
-#include <simgear/math/interpolater.hxx>
-#include <simgear/structure/subsystem_mgr.hxx>
-
-
-class Encoder : public SGSubsystem
-{
-public:
-    Encoder(SGPropertyNode *node);
-    ~Encoder();
-
-    void init ();
-    void update (double dt);
-
-private:
-    // Inputs
-    SGPropertyNode_ptr staticPressureNode;
-    SGPropertyNode_ptr busPowerNode;
-    SGPropertyNode_ptr serviceableNode;
-
-    // Outputs
-    SGPropertyNode_ptr pressureAltitudeNode;
-    SGPropertyNode_ptr modeCAltitudeNode;
-
-    // Internal
-    string _name;
-    int _num;
-    string _static_pressure;
-
-    SGInterpTable* altitudeTable;
-};
-
-#endif // ENCODER_HXX