message sent from the aircraft's communications system, called acars. richard quest is an anchor and aviation correspondent for cnn. >> think of acars as a giant smartphone that will send out huge amounts of information. via satellite or by radio transmission. >> then at 1:19 a.m., a standard handoff with air traffic control as the plane leaves malaysian airspace and enters vietnamese airspace. >> the controller here in malaysia tells him to speak to ho chi minh. and he says good night, malaysian 370, something i would do. >> there was no indication that anything had gone wrong. >> david sousi is a former safety inspector for the faa.