Updated at 1:31 p.m. ET
(AP) JAKARTA, Indonesia - A new Russian-made passenger plane went missing over mountains in western Indonesia while on a demonstration flight Wednesday arranged for potential buyers. Fifty people were on board, including diplomats, businesspeople and journalists.
Search and rescue teams were deployed to the area just south of the capital, Jakarta, said Bambang Ervan, a spokesman for the Ministry of Transportation. He said more than 100 people were still searching the rugged, forested terrain after darkness fell. Bad weather, however, forced at least two helicopters to turn back.
The Sukhoi Superjet-100, Russia's first new passenger jet since the fall of the Soviet Union, took off from the Halim Perdanakusuma Airport at 2:21 p.m. (3:21 a.m. ET) for what was supposed to be a quick test flight the second of the day.
It dropped off the radar just 21 minutes later, shortly after the crew asked air traffic control for permission to drop from 10,000 feet to 6,000 feet, said Daryatmo, chief of the national search and rescue agency.
They didn't explain the change of course, which occurred near Salak mountain, a long-dormant volcano, he said. Though drizzling at the time, it was not stormy, and there was no obvious sign of distress.
Cellphones of those on board were either turned off or not active.
"I saw a big plane passing just over my house," Juanda, a villager who lives near the 7,200-foot mountain, told local station TVOne.
"It was veering a bit to one side, the engine roaring," he said. "It seemed to be heading toward Salak, but I didn't hear an explosion or anything."
Dozens of family members gathered at the airport, awaiting news about their loved ones. Many were crying. Some were clinging to young, sleepy children.
"My husband called this morning, saying he was going to be on the test flight," said Windy Prisilla. "He wanted me to meet him at the airport before they took off so we could have lunch together, but I told him I couldn't. I had to get the kids to school."
"All I can do now is pray to God. I want him back home safely," she said, barely able to speak.
Daryatmo, of the search and rescue agency, said soldiers, police and air force personnel were helping to look for the plane.
"Hopefully they'll be able to reach the location tonight," Daryatmo said, adding that helicopters were ready to return at daybreak if necessary.
The Superjet has been widely considered Russia's chance to regain a foothold in the international passenger plane market. The country's aerospace industry was badly undermined in the economic turmoil following the 1991 collapse of the Soviet Union.
Developed by the civil aircraft division of Sukhoi with the co-operation with Western partners the 75- to 95-seat plane made its maiden voyage in 2008 and its inaugural commercial passenger flight in 2011.
With a relatively low price tag of around $35 million, it has been seen as a potential challenger to similar-sized jets from Canada's Bombardier Inc. and Brazil's Embraer SA.
Around 170 orders have already been placed worldwide, with Indonesia, a sprawling archipelagic nation of 240 million people, among the biggest potential customers.
Kartika Airlines one of dozens of airlines that have popped up in Indonesia in the last decade to meet the growing demand for cheap air travel had been planning to buy 30.
It was unclear if Wednesday's incident would change that.
Most appeared to be waiting to see whether the problem was mechanical or pilot error.
Among the 50 people on board the plane were potential buyers from several major local airlines. Reporters also filled seats as did several people from the Russian Embassy, said Daryatmo.
The plane was on the fourth stop of a six-nation "Welcome Asia!" road show after having already been to Burma, Pakistan and Kazakhstan. It was to head next to Laos and Vietnam.