Does anyone know the approximate turning radius of AA77 on its final down screw towards the Pentagon?

I have found a dubious link based on allegedly released data from the airplanes data recorder (not containing any NTSB identification logo) which puts the radius at 3.2 miles. With this radius, the turning was not a feat, but a long protracted yawn...

http://gluonconleche.blogspot.com.ar/2006/12/un-giro-imposible.html