A brand new Russian "Superjet" carrying 46 people has disappeared from radar during a demonstration flight over West Java in Indonesia, officials have said.
The crew of the Sukhoi Superjet-100 had asked for permission to descend from 10,000ft to 6,000. The Indonesian military said the plane dropped from the sky. It was carrying Indonesia businessmen and Russian embassy officials.
"The plane was doing the first flight and returned to the airport but when it took off the second time, it lost contact around Bogor," said Bambang Ervan, the transport ministry spokesman.
The aircraft might have crashed on a nearby 6,200ft mountain or been hijacked, said Indonesian authorities.
It had already experienced problems while being flown by Russian flag-carrier Aeroflot. In March, a plane had to cut short a scheduled flight after it met problems with its undercarriage, AFP reports.
The plane was operated by senior test pilot Aleksandr Yablontsev and co-pilot Aleksandr Kochetkov.
Post-Soviet hopes for Russia
A spokeswoman for Russia's United told Reuters that the plane was on a second flight as part of a demonstration programme in Indonesia called Asian Roadshow, aimed at promoting the aircraft abroad. It was due to fly on to Laos and Vietnam.
"The first flight was carried out in a normal mode. The pre-flight preparations were carried out in full and the plane was ready to fly," she said.
"According to information from Indonesia, the contact with the plane was broken after 20 minutes from take-off, at 1435 local time. Search works are under way."
Russia built the Sukhoi Superjet 100 to boost its civil aviation industry. It was seen as fundamental to the country's hopes of becoming a major player in the modern aviation market.
A major accident, if confirmed, would shatter Russia's image and plunge it back to the Soviet-era days of frequent air crashes and faulty aircraft.
The Superjet project is a joint venture between legendary Sukhoi and Italy's Alenia Aeronautica, which is part of the aerospace and defence giant Finmeccanica.
People flocked to Twitter to comment on the loss of the plane. "#Russia should stick to exporting arms and oil. One of life's little rules: never fly a Russian passenger jet," tweeted investigative journalist James Henry.
Shiv Aroor at Headlines Today tweeted: "Russia banks on the Sukhoi Superjet program to put it back in the global civil airliner market. Big blow if the jet has crashed. Prayers."