passengers and 12 crew on board. 26 minutes into the flight, at 1:07 a.m., one of the plane's critical communications sends its final transmission. the on board computer is called the aircraft communications addressing and reporting system, or acars. it measures thousands of data points about the plane and pilots' performance and sends the information via satellite. it is due to transmit again at 1:37 a.m., but never does. 1:19 a.m., someone inside the cockpit -- believed to be the co-pilot -- provides the last verbal communication with air traffic controllers. his last words "all right. good night." it's a common good-bye to controllers after being handed off. at 1:21 a.m., the transponder which identifies the plane to civilian radar, goes off. critical information like the plane's flight number, height, speed, and heading are all cut