"This tragedy illustrates that systems such as signage and fencing can fail. The purpose of having backup systems is that failure of one does not necessarily result in tragedy." That was a comment on November 26 last year by Judge Greg Cavanagh in his Coronial report about Wilfried Thor and Gisela Thor (pictured) who perished at Threphina Gorge. Five weeks later, possibly on January 2 this year, Monika Billen was dead in similar circumstances. The government and the industry are not answering questions – so far – put to them by the Alice Springs News Online. Report by ERWIN CHLANDA.