Air India Crash: What Brought The Plane Down In Just 40 Seconds?

Over 270 people died in the crash of Air India Flight AI171, just 40 seconds after take-off. One week later, India is still waiting for answers. Was it a rare dual engine failure? What did the pilot say in the Mayday call? NDTV's Parmeshwar Bawa takes you through the 10 big unanswered questions, 1 week after the deadly Air India crash.