diff --git a/libraries/SITL/SIM_Plane.cpp b/libraries/SITL/SIM_Plane.cpp
index d25bea6760..7ab61159cd 100644
--- a/libraries/SITL/SIM_Plane.cpp
+++ b/libraries/SITL/SIM_Plane.cpp
@@ -258,7 +258,7 @@ Vector3f Plane::getForce(float inputAileron, float inputElevator, float inputRud
     return Vector3f(ax, ay, az);
 }
 
-void Plane::calculate_forces(const struct sitl_input &input, Vector3f &rot_accel, Vector3f &body_accel)
+void Plane::calculate_forces(const struct sitl_input &input, Vector3f &rot_accel)
 {
     float aileron  = filtered_servo_angle(input, 0);
     float elevator = filtered_servo_angle(input, 1);
@@ -380,7 +380,7 @@ void Plane::update(const struct sitl_input &input)
 
     update_wind(input);
     
-    calculate_forces(input, rot_accel, accel_body);
+    calculate_forces(input, rot_accel);
     
     update_dynamics(rot_accel);
     update_external_payload(input);
diff --git a/libraries/SITL/SIM_Plane.h b/libraries/SITL/SIM_Plane.h
index 4034a8d194..b5db14f3ea 100644
--- a/libraries/SITL/SIM_Plane.h
+++ b/libraries/SITL/SIM_Plane.h
@@ -121,7 +121,7 @@ protected:
     float dragCoeff(float alpha) const;
     Vector3f getForce(float inputAileron, float inputElevator, float inputRudder) const;
     Vector3f getTorque(float inputAileron, float inputElevator, float inputRudder, float inputThrust, const Vector3f &force) const;
-    void calculate_forces(const struct sitl_input &input, Vector3f &rot_accel, Vector3f &body_accel);
+    void calculate_forces(const struct sitl_input &input, Vector3f &rot_accel);
 };
 
 } // namespace SITL
diff --git a/libraries/SITL/SIM_QuadPlane.cpp b/libraries/SITL/SIM_QuadPlane.cpp
index 0b99c52995..8127d0c0e7 100644
--- a/libraries/SITL/SIM_QuadPlane.cpp
+++ b/libraries/SITL/SIM_QuadPlane.cpp
@@ -107,7 +107,7 @@ void QuadPlane::update(const struct sitl_input &input)
 
     // first plane forces
     Vector3f rot_accel;
-    calculate_forces(input, rot_accel, accel_body);
+    calculate_forces(input, rot_accel);
 
     // now quad forces
     Vector3f quad_rot_accel;