+// return the amount of cross track distance error, returns a meters
+double FGNavCom::get_nav_cdi_xtrack_error() const {
+ double r, m;
+
+ if ( nav_inrange
+ && nav_serviceable->getBoolValue() && cdi_serviceable->getBoolValue() )
+ {
+ r = nav_radial - nav_target_radial;
+ // cout << "Target radial = " << nav_target_radial
+ // << " Actual radial = " << nav_radial
+ // << " r = " << r << endl;
+
+ while ( r > 180.0 ) { r -= 360.0;}
+ while ( r < -180.0 ) { r += 360.0;}
+ if ( fabs(r) > 90.0 )
+ r = ( r<0.0 ? -r-180.0 : -r+180.0 );
+
+ r = -r; // reverse, since radial is outbound
+
+ m = nav_loc_dist * sin(r * SGD_DEGREES_TO_RADIANS);
+
+ } else {
+ m = 0.0;
+ }
+
+ return m;
+}