A Russian-made plane carrying 50 people has gone missing in the southern mountainous regions of Jakarta, Indonesia.

The Sukhoi Superjet 100 fell off radars around 5:30 p.m. Wednesday, Korea time, during a demonstration flight with Russians, Italians and Indonesians on board.

Indonesian authorities have launched a search and mobilized helicopters around the area where the plane went missing, but the rescue efforts have largely been in vain due to inclement weather conditions.

Indonesia’s aviation authorities have not ruled out the possibility that the plane crashed in the mountains.

The Sukhoi Superjet 100 is a mid-sized aircraft that Russia has actively been promoting sales of around the world.