Unanswered Questions Linger One Year After China Plane Crash

China's aviation regulator is still investigating the cause of the crash of China Eastern Airlines' Flight MU5735, which killed all 132 people on board almost a year ago. The investigation is focusing on how key components were performing before the crash, air traffic control, the passengers, and what the plane was carrying. The cockpit voice recorder and flight data recorder were sent to a U.S. National Transportation Safety Board laboratory in Washington, and a final report into the causes of the crash could take two years or more to compile.