Jakarta:
Indonesian special forces traversed the sheer slope of a volcano to try to reach the voice and flight data recorder of a new Russian-made passenger jet that crashed during a demonstration flight for potential buyers.
It is not clear what caused the Sukhoi Superjet-100 to roar into Mount Salak at 800 kph last week. All 45 people aboard are presumed dead, and helicopters have been ferrying the remains to Jakarta, the capital, for identification.
Search teams say that they spotted what is believed to be the voice and flight data recorder, also known as the "black box," peeking from the wreckage at the bottom of a 500-meter ravine, said Tatang Kurniadi, who heads the National Transportation Safety Commission.
"We are really hoping they'll reach it sometime today," he said.
The Superjet Russia's first new model of passenger jet since the fall of the Soviet Union two decades ago was in Indonesia as part of a six-nation Asian tour aimed at getting new customers.
It was making its second demonstration flight of the day when the crew sought permission to drop from 3000 meters to 1800 meters just 12 minutes after takeoff.
They gave no explanation and disappeared from the radar immediately afterward.
Investigators and aviation experts have many questions. One is why the pilot and co-pilot asked to descend so close to a jagged mountain range that is notoriously dangerous, with six smaller plane crashes in the last decade.
Satellite imagery indicates heavy rain and dense clouds covered the peak at the time of the crash.
Even so, such planes are almost always fitted with ground proximity warning systems, which display the positions and heights of obstructions, natural and man-made, on a screen in the cockpit.
That should have greatly reduced the chances for such an accident.
"Perhaps the system was not installed, or for some reason was not turned on," said Patrick Smith, an American airline pilot and aviation author. "On the other hand, at this juncture, we have no idea what was going on up there. It's too early to try and pinpoint a cause."
The emergency locator, which should have transmitted signals on various radio frequencies when it slammed into the cliff Wednesday, also did not work. That slowed efforts to locate the shattered wreckage.