if it was an instrument flight there was a big navigation error. With high ground to the
Sorry, but where is your evidence to back up that statement? Beacon to beacon or beacon to point or beacon to range/radial are valid IFR navigation techniques. Admittedly these chaps or chapesses were in the wrong place at the wrong time when some LOC/UA/technical event occured but it remains to be seen whether they were playing by the rules or not.