Russia's newest civilian airliner disappeared Wednesday from radar screens during a half-hour demonstration flight in the Indonesian capital, Jakarta, state-run RIA Novosti news service reported. There were 44 passengers on board. The plane went missing at about 2 p.m. in the area of Bogor, West Java, Indonesian Transportation Ministry spokesman Bambang Ervan told Metro TV. The pilots requested permission to descend from 10,000 feet to 6,000 feet, air traffic controllers said. After that, all radio contact was lost. The plane began making its descent but vanished from radar screens at 6,200 feet in a mountainous area. By the time the plane was due to return it should have burned up its fuel, RIA Novosti said. The Sukhoi Superjet 100 airplane arrived in Jakarta as part of a demonstration tour of six Asian countries. It had been to Myanmar, Pakistan and Kazakhstan, and was due to visit Laos and Vietnam after Indonesia, RIA Novosti said. Sukhoi manufactures military aircraft and is known especially for its fighter jets. Its civilian aircraft is narrow-bodied with a dual-class cabin that can transport 100 passengers over regional routes. It flew its maiden flight in 2008. In March, a Superjet 100 operated by Russia's Aeroflot Airlines was forced to abandon its flight to Astrakhan, Russia, and return to Moscow because of problems with the undercarriage, according to RIA Novosti. A similar defect in another Aeroflot-operated Superjet 100 plane had to be fixed in Minsk in December. Russia's state-run United Aircraft Corp. said the defect did not affect passenger safety.