Search teams Monday found an emergency transmitter from the Russian jet that slammed into a dormant volcano in Indonesia but said they are yet to locate the flight recorders that could explain the deadly crash.
Russian experts and Indonesian searchers combing the remote area where the Sukhoi Superjet 100 crashed Wednesday, killing all 45 on board, found the emergency locator transmitter (ELT) and other instruments in a deep ravine on Mount Salak.
The old-model transmitter, which sends out a distress signal in the event of a crash, would not have been able to communicate via satellite but was designed to be picked up by rescuers on the ground, or by airport control towers, rescue chief Daryatmo said.
Officials have said they did not receive a signal after the accident.
Dozens of Russian experts have flown to Indonesia in recent days to join the investigation.
Some are assisting Indonesian teams at the crash site, south of the capital Jakarta, where the tail of the plane was on Sunday located in a 500-metre deep ravine.
Sukhoi Civil Aircraft spokeswoman Olga Kayukova told AFP on Monday that the plane that crashed was not the same one that carried out the first part of the Asia promotional tour in Kazakhstan and Pakistan.
She said the first model had returned to Moscow "to take part in tests", without giving further details, but insisted the second jet was in "perfect technical condition before the flight".
The aircraft, a joint venture between Sukhoi and Italy's Alenia Aeronautica, made its first commercial flight last year.
Most of the 45 who died on board were Indonesian airline representatives -- potential customers of the Sukhoi jet -- the first post-Soviet new passenger plane produced by Russia.