The Sukhoi Superjet-100, Russia's first passenger jet since the fall of the Soviet Union, was carrying 45 people, including several diplomats from the Russian embassy, potential buyers from major Indonesian airlines and journalists.
It was a flight that was supposed to be only 50 minutes long. The plane dropped off the radar 21 minutes after take-off from the airport in Jakarta.
The Russian pilot and co-pilot had asked air traffic control for permission to drop from 10,000 feet to 6,000 feet, but they gave no explanation. Authorities will be reviewing communication tapes as part of their investigation.
The Associated Press contributed to this report.