Recovery teams have found human remains at the crash site of the China Eastern jet which plunged into mountains this week, say state media.
Authorities have yet to declare the number of victims, but there has been no sign so far that any of the 132 people onboard had survived.
Investigators still do not know why the plane suddenly entered a near-vertical dive in southern China on Monday.
But the recovery of the intact cockpit voice recorder is hoped to shed clues.
The black box was found damaged on the outside but its internal records appeared to be fine, officials said. It has been sent to Beijing for its data to be analysed.
Search teams found the first of the crucial black boxes in difficult circumstances on Wednesday.
On Wednesday, dozens of family members of those onboard the flight began to arrive at the scene. Escorted by officials and supporters, many kept their heads bowed as they passed gathered media but some spoke briefly to journalists about their loss.
One man told Reuters his nephew had been a passenger on the flight. He and his son had driven five hours from neighbouring Shenzhen province in the hopes of being able to find their relative alive.
“I plan to stay until the matter is sorted and I can take his ashes back. But this depends on the work of authorities.
“I hope the country can thoroughly investigate this matter and find out whether it is the manufacturer’s fault or a maintenance problem.”
The crash of the passenger plane this week – which had been on a short domestic flight from Kunming to Guangzhou on the coast- has shocked and devastated China. The country has had a strong air safety record over the past three decades.
President Xi Jinping swiftly ordered a full-scale investigation into the tragedy, dispatching Vice Premier Liu He and hundreds of personnel to the rural hillside region in Guangxi province.