A year on, six questions still haunt the Air India crash investigation

A year after Air India Flight 171 to London crashed into a medical college campus moments after take-off from the western Indian city of Ahmedabad, killing 260 people, investigators still cannot say with certainty why one of the world's most advanced passenger jets fell from the sky. An update released by India's Aircraft Accident Investigation Bureau (AAIB) on the first anniversary of the disaster on Friday offered few new clues, saying only that analysis of flight recorder data, aircraft systems, engine components, maintenance records and human factors remains under way.