new Delhi, July 18 -- A cockpit voice recording of doomed Air India Flight 171 indicates the younger co-pilot asked his more experienced colleague why he turned off the plane's fuel-supply switches, according to people familiar with the matter. The information, from people who asked not to be identified because they're not authorized to speak publicly, reveals for the first time who said what in the flight deck. The exchange was first mentioned in last week's preliminary report from India's Aircraft Accident Investigation Bureau probing the June 12 crash in the western city of Ahmedabad, but without identifying the speakers. The report had shown two fuel switches in the cockpit were moved to a cut-off position, causing the Boeing Co. 787 Dreamliner to lose lift and crash 32 seconds after takeoff. The other pilot had denied turning off the switches, according to the AAIB, which had extracted data from the cockpit voice recorder. Aviation experts had speculated that it was first officer Clive Kunder who had posed the question to captain Sumeet Sabharwal given Kunder was the pilot flying and would have had his hands full - one on the yoke commanding the widebody into the skies, and the other on the throttle controlling the aircraft's speed. The Wall Street Journal previously reported who said what in the exchange. The initial investigation showed that the fuel-control switches were turned off immediately after the plane departed. While the move was reversed about 10 seconds later, it was too late to avert the June 12 crash that killed 260 people on board the plane and on the ground. How and why the switches came to be turned off - cutting the flow of fuel to the engines - are now the key lines of inquiry for investigators. Officials are probing whether it could be the result of a failure of the plane's systems or human error. And while the new details add fresh perspective on the confusion in the cockpit during the 32 seconds between takeoff and crash, investigators still haven't drawn any definitive conclusions. The cockpit recording could be even more revelatory, according to Michael Daniel, a retired Federal Aviation Administration inspector and accident investigator. "There are multiple microphones around the cockpit including their headsets," said Daniel. The mic positions mean it's possible that it captured and discerned not just the sound of the fuel switches being turned off, but the direction from which it came in the cockpit - offering investigators definitive information as to who cut off fuel supply to the planes engines, he said. Earlier this week, India's civil aviation authority ordered an inspection of cockpit fuel switches on Boeing 737 and 787 aircraft operating in the country in an effort to ascertain whether the crash was caused by equipment failure. Aviation psychologists and medical specialists are also involved in the investigation - a typical practice across the aviation industry - to probe the role of the pilots in the crash. The first officer expressed surprise that the fuel switches were off and then panicked, the Wall Street Journal reported, citing people familiar with US officials' early assessment of evidence. The captain seemed to remain calm, according to the report....