Indonesia says it could take as long as a year to analyze equipment and flight data recovered from the crash site of a Russian jetliner that slammed into the side of a volcano last week near Jakarta, killing all 45 people on board.

Aviation authorities, quoted in Indonesian media Wednesday, said the crash probe will at a minimum take four months — in part to ensure reliable results. National Transportation Safety Committee chief Tatang Kurniadi also told the Jakarta Globe newspaper that Russia's role in the probe will be limited to potential problems that require explanation from Moscow.

The reports said Russia had previously asked that the “black box” containing flight data, which was recovered from the crash site, be sent for analysis to Moscow. The data normally includes cockpit conversations and communications with air traffic controllers. But the reports said Indonesia turned down the Russian request.

Separately, the Jakarta Post newspaper quoted aviation officials Wednesday who said they suspect the Sukhoi Superjet 100 had departed from its planned flight path before striking the side of Mount Salak at nearly 500 kilometers an hour.

The doomed jetliner, which was on a promotional sales tour, took off from Jakarta's Halim Airport on May 9 with an entourage of prospective buyers, journalists and crew.

It was expected to return in less than an hour. But the plane dropped in altitude from 3,000 to 1,800 meters and lost contact with air traffic control. Mount Salak is 2,200 meters high.