diff --git a/ArduPlane/Plane.h b/ArduPlane/Plane.h
index dd9f09257c..b9e4312600 100644
--- a/ArduPlane/Plane.h
+++ b/ArduPlane/Plane.h
@@ -717,7 +717,6 @@ private:
     float lookahead_adjustment(void);
     float rangefinder_correction(void);
     void rangefinder_height_update(void);
-    void add_altitude_data(unsigned long xl, long y);
     void set_next_WP(const struct Location &loc);
     void set_guided_WP(void);
     void init_home();
diff --git a/ArduPlane/climb_rate.cpp b/ArduPlane/climb_rate.cpp
deleted file mode 100644
index cc763c0f4a..0000000000
--- a/ArduPlane/climb_rate.cpp
+++ /dev/null
@@ -1,62 +0,0 @@
-// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-
-#include "Plane.h"
-
-#if 0 // currently unused
-
-struct DataPoint {
-    unsigned long x;
-    long y;
-};
-
-DataPoint history[ALTITUDE_HISTORY_LENGTH];               // Collection of (x,y) points to regress a rate of change from
-unsigned char hindex;   // Index in history for the current data point
-
-unsigned long xoffset;
-unsigned char n;
-
-// Intermediate variables for regression calculation
-long xi;
-long yi;
-long xiyi;
-unsigned long xi2;
-
-void add_altitude_data(unsigned long xl, long y)
-{
-    //Reset the regression if our X variable overflowed
-    if (xl < xoffset)
-        n = 0;
-
-    //To allow calculation of sum(xi*yi), make sure X hasn't exceeded 2^32/2^15/length
-    if (xl - xoffset > 131072/ALTITUDE_HISTORY_LENGTH)
-        n = 0;
-
-    if (n == ALTITUDE_HISTORY_LENGTH) {
-        xi -= history[hindex].x;
-        yi -= history[hindex].y;
-        xiyi -= (long)history[hindex].x * history[hindex].y;
-        xi2 -= history[hindex].x * history[hindex].x;
-    } else {
-        if (n == 0) {
-            xoffset = xl;
-            xi = 0;
-            yi = 0;
-            xiyi = 0;
-            xi2 = 0;
-        }
-        n++;
-    }
-
-    history[hindex].x = xl - xoffset;
-    history[hindex].y = y;
-
-    xi += history[hindex].x;
-    yi += history[hindex].y;
-    xiyi += (long)history[hindex].x * history[hindex].y;
-    xi2 += history[hindex].x * history[hindex].x;
-
-    if (++hindex >= ALTITUDE_HISTORY_LENGTH)
-        hindex = 0;
-}
-#endif
-