diff --git a/libraries/AP_Math/AP_Math.cpp b/libraries/AP_Math/AP_Math.cpp
index 1419554b08..20e49f9264 100644
--- a/libraries/AP_Math/AP_Math.cpp
+++ b/libraries/AP_Math/AP_Math.cpp
@@ -32,13 +32,6 @@ float safe_sqrt(float v)
     return ret;
 }
 
-// a faster varient of atan.  accurate to 6 decimal places for values between -1 ~ 1 but then diverges quickly
-float fast_atan(float v)
-{
-    float v2 = v*v;
-    return (v*(1.6867629106f + v2*0.4378497304f)/(1.6867633134f + v2));
-}
-
 #if ROTATION_COMBINATION_SUPPORT
 // find a rotation that is the combination of two other
 // rotations. This is used to allow us to add an overall board
diff --git a/libraries/AP_Math/AP_Math.h b/libraries/AP_Math/AP_Math.h
index 2fd3714ef1..9b31635887 100644
--- a/libraries/AP_Math/AP_Math.h
+++ b/libraries/AP_Math/AP_Math.h
@@ -88,9 +88,6 @@ float           safe_asin(float v);
 // a varient of sqrt() that always gives a valid answer.
 float           safe_sqrt(float v);
 
-// a faster varient of atan.  accurate to 6 decimal places for values between -1 ~ 1 but then diverges quickly
-float           fast_atan(float v);
-
 #if ROTATION_COMBINATION_SUPPORT
 // find a rotation that is the combination of two other
 // rotations. This is used to allow us to add an overall board