It may take experts up to 15 months to investigate the crash of a Russian-made Sukhoi Superjet 100 aircraft in Indonesia, a representative of the Indonesian transport security committee said on Friday.

The probe is unlikely to be completed promptly because of “complex conditions” in the area where the aircraft crashed, he said.

The plane slammed into a steep mountainside at Mount Salak, outside the capital Jakarta, during a demonstration flight on Wednesday. There were 45 people on board, including eight Russians, one American, one French, two Italians and 33 Indonesians.

On Friday morning, a search operation continued in the area of the crash. The nearly vertical face of Mount Sakal has made search efforts extremely difficult.

The searchers have so far discovered no sign of any crash survivors. Rescue teams in helicopters have so far only found parts of the aircraft's tail, local media reported on Friday. The aircraft's flight data recorders have yet to be found.

At 9 a.m. local time (02:00 GMT), an advance team of 10 Indonesian searchers was 600 meters away from the crash site, the Detik.com online news portal said. The team has been trying to clear a site for helicopter landing, the report said, quoting a spokesman for Indonesia’s rescue service.

Six helicopters have been sent to the area. One of them is carrying Leonid Kashirsky, an official from the Interstate Aviation Committee, the Moscow-based body that carries out crash investigations in the CIS .

© RIA Novosti.

Superjet-100 Crashes in Indonesia

Russia’s acting Deputy Prime Minister Dmitry Rogozin said on Thursday experts believe the "human factor" was the most probable cause of the fatal crash. He maintained the aircraft is competitive and has “a bright future,” despite the tragic crash.

The Sukhoi Superjet-100 is Russia's first new passenger jet since the fall of the Soviet Union and is designed to replace the obsolete Tu-134 and Yak-42.