Indonesian searchers scaled a steep volcano Friday to retrieve at least 45 bodies from the jungly terrain where a Russian jet crashed, as questions mounted over how a new plane with a veteran pilot flew into a mountain.
Crews were using climbing equipment including ropes to ascend the near-vertical face of Mount Salak and were believed to be about 200 metres (650 feet) from reaching the first bodies, authorities said.
All aboard the twin-engine Sukhoi Superjet 100 were killed, authorities said Thursday, a day after the plane slammed into the dormant volcano during a demonstration flight that was meant to spur international sales of Russia's first post-Soviet civilian jet.
The passenger aircraft descended from 10,000 feet (3,000 metres) to 6,000 feet before slamming into Mount Salak, which juts 7,200 feet into the sky south of Jakarta, authorities said.
Controversy swirled over why the 57-year-old, vastly experienced Russian captain descended so low over mountainous terrain. Others questioned whether the jet, which has already experienced some troubles while being flown by flag carrier Aeroflot, encountered an unknown emergency in a tricky air corridor.
"Why did the Sukhoi descend, and who cleared it?" said a headline in the English-language Jakarta Post. Authorities have only confirmed that the plane descended, without saying whether it was cleared by air traffic control.
The authorities will be keen to locate the plane's black boxes, which may help to resolve the unanswered questions.
Wednesday's calamity came 50 minutes into a brief flight that was part of an Asian sales tour to promote the aircraft, a joint venture between Sukhoi and Italy's Alenia Aeronautica, which made its first commercial flight last year.
Gerry Soejatman, an aviation consultant and amateur pilot who is familiar with the air corridor around Mount Salak, said it was not the place for an exhibition flight.
"I don't recommend the area around Mount Salak for a low-level flight, especially for someone who's never flown in the area," he told AFP.
"Very few pilots would actually fly around there without any particular purpose, because of the pass between the mountains, which is open to fast-changing weather conditions," he said.
In Moscow, investigators have opened a criminal probe to look into possible misconduct during preparations for the flight as well as the plane's technical condition before it left Russia.
The loss of the Superjet is a heavy blow to the Russian aviation industry, which was hoping that the new plane would improve its image.
But Sukhoi's agent in Jakarta said there was no talk of suspending sales in Indonesia, Southeast Asia's largest economy and an archipelago of more than 17,000 islands where air travel and airlines are booming.
Near the crash site, the military commander of the rescue mission said that one team was climbing up from the foot of the mountain, while another was going down from the top.
The difficult terrain, which most days is shrouded in thick fog, has been an extreme challenge to the searchers.
The mist had stopped helicopters from getting close to the area, since a chopper pilot first spotted the wreckage Thursday morning, authorities said.
"The plane crashed into the mountain and slid 250 metres down, to 1,800 metres," said the commander, Colonel Anton Mukti Putranto.
"There is so far no information about (the number of) victims. They could see only the debris of the plane because it's still quite a distance from where they are," Putranto said, referring to the team closest to the site.
The company representing Sukhoi in Indonesia, Trimarga Rekatama, originally said 50 passengers were on board but Thursday revised the number to 45. Local rescue officials said the plane was carrying 46 people.
Those aboard were mostly Indonesian aviation representatives, but there were also eight Russians -- four of them crew and four Sukhoi employees -- plus an American and a Frenchman, officials said.
Ketut Parwa, search and rescue agency chief for Jakarta, said victims would be placed into body bags, hoisted up the mountain, then carried to ambulances a long distance away on foot. Helicopters would then fly the bodies to Jakarta for identification.