Indonesian officials say a helicopter has spotted¹ what is thought to be wreckage² of the Russian Sukhoi Superjet plane that disappeared on Wednesday.

印度尼西亚官方发表消息称，一架直升机发现了某飞机残骸，该残骸可能是本周三消失的俄罗斯苏霍伊超级喷气式飞机。

Wreckage was spotted after an aerial search of the area where the plane lost contact
The Sukhoi Superjet 100 vanished from radar³ screens 50 minutes after taking off from Jakarta for a brief demonstration⁴ flight.

Officials said the helicopter had seen debris⁵ on the side of a cliff near a dormant⁶ volcano（休眠火山） .

About 45 people are said to have been on board the aircraft.

"The aeroplane crashed at the edge of Salak mountain," Indonesian President Susilo Bambang Yudhoyono said on television.

"I have spoken directly to our officer in the field, it was found around 1.5km (one mile) from the spot where the plane last made contact," he said.

"An investigation⁷ must be carried out immediately and thoroughly⁸. Search and rescue operations must prioritise finding any survivors⁹."

There was no sign of any passengers but rescuers were preparing to drop a team from a helicopter onto the ridge¹⁰ to search for survivors, a military official said.

Eight Russian pilots and technicians, Indonesian airline representatives and journalists were among those said to be on board the plane.

Earlier reports had said 50 people were on board, but Indonesian agents of the Russian-made plane told the BBC this figure had been revised down because some people got off before take-off.

Sales tour

Aerial searches for the plane on Wednesday were hampered¹¹ by darkness and strong winds. Fog early on Thursday also delayed search efforts.

The plane took off from east Jakarta's Halim Perdanakusuma airport at 14:00 (07:00 GMT) on Wednesday, on its second flight of the day.

At 14:50, it was recorded as dropping from 10,000ft (3,000m) to 6,000ft near Salak, a peak measuring 7,200ft (2,200m).

Juanda, a villager who lives near the mountain, told local TV: "I saw a big plane passing just over my house."

Rescue teams on the ground were working to reach the site where the debris was spotted, officials said.

Sukhoi officials have been on an Asia-wide tour in recent months to show off their aircraft to airline firms.

The Superjet, a mid-range airliner¹² that can carry up to 100 people, is military plane-maker Sukhoi's first commercial aviation plane.

It was created by a joint¹³ venture, majority-owned by Sukhoi, with Italy's Finmeccanica and a number of other foreign and Russian firms also involved.

Sukhoi aimed to sell 42 of its planes to Indonesia, which has witnessed a fast-expanding aviation market to cater¹⁴ for a growing middle class in the world's fourth most populous¹⁵ nation, Reuters adds.