"This morning I had an official report from the National Transportation Safety Committee. At 7:11 we had succeeded in lifting the part of the black box known as the flight data recorder," Fransiskus Bambang Soelistyo, head of the search and rescue agency, told a news conference.
"We are still trying to find the cockpit voice recorder."
Divers began to zero in on the site a day earlier after picking up intense pings from its beacons, but they were unable to get a visual on it due to strong currents and poor visibility.
The cockpit voice and flight data recorders are vital to understanding what brought Flight 8501 down on Dec. 28, killing all 162 people on board.
Flight QZ8501 vanished from radar screens over the northern Java Sea on Dec. 28, less than half-way into a two-hour flight from Indonesia's second-biggest city of Surabaya to Singapore.