Question posed in slot #289, from PJ2:
"... what is the source of the information ... statements about runway length used, tailwind component etc? The "4000ft" figure ... where did it come from?"
Suspect the initial "float" estimate was returned from the manufacturer's Runway Track Analysis Program:
_TRAJECTORY RECONSTRUCTION TOOL FOR INVESTIGATION OF RUNWAY OVERRUNS_
www.cta-dlr2009.ita.br/Proceedings/PDF/59024.pdf"... software tool is conceived to calculate the aircraft’s trajectory from the final approach to the touchdown point on the runway. This tool performs its calculations based on data recorded by the Flight Data Recorder (FDR) ...
"... tool is built up by two different calculation methods. The first is the Instrument Landing System (ILS) method. The second is based upon the integration of the rigid-body aircraft’s Equations of Motion. The reason for using a dual method approach lies on the first method’s incapacity to reconstruct the trajectory all the way to the touchdown point...."