What caused South Korea's deadliest plane crash?

South Korea is now in seven days of mourning after 179 people were killed in the deadliest aviation disaster the country has ever seen. The plane, which was flying from Thailand to Muan International Airport in South Korea, was attempting an emergency landing when it crashed.  There were only two survivors. Today, US aviation industry consultant Scott Hamilton speaks with ABC News Radio's Sarah Mourice about what could have happened in the cockpit moments before the tragedy.  Featured: Scott Hamilton, US aviation industry consultant Leeham Company