Indonesia's military chief said on Sunday divers have spotted parts of the wreckage of a Boeing 737-500 at a depth of 23 meters (75 feet) in the Java Sea, a day after the aircraft with 62 people onboard crashed.
"We received reports from the diver team that the visibility in the water is good and clear, allowing the discovery of some parts of the plane," Air Chief Marshal Hadi Tjahjanto said in a statement.
He said: "We are sure that is the point where the plane crashed."
He said the objects included broken pieces of fuselage with aircraft registration parts.
Earlier, rescuers pulled out body parts, pieces of clothing and scraps of metal from the surface.
"As of this morning, we've received two (body) bags, one with passenger belongings and the other with body parts," Jakarta police spokesman Yusri Yunus told Metro TV.
— Flightradar24 (@flightradar24) January 9, 2021
The break in the search for Sriwijaya Air Flight 182 came after sonar equipment on a navy ship detected a signal from the aircraft at a location that fit the coordinates from the last contact made by the pilots before the plane went missing on Saturday afternoon.
"Hopefully until this afternoon the current conditions and the view under the sea are still good so that we can continue the search," Mr Tjahjanto said.
Helicopters were also on standby at an airport near Jakarta to launch a search from the air.
The Indonesian meteorological agency has warned of a risk of heavy rain and strong winds that could hamper the search and rescue efforts.
More than 12 hours since the Boeing plane operated by the Indonesian airline lost contact, little is known about what caused the crash and there was no signs of survivors.
"I represent the government and all Indonesians in expressing my deep condolences for this tragedy," President Joko Widodo said.
"We are doing our best to save the victims. We pray together so that the victims can be found," he said, adding that he had asked the National Transport Safety Committee to conduct an investigation.
The Boeing 737-500 was carrying 50 passengers – including ten children - and 12 crew was en route to Pontianak in West Kalimantan province on Indonesia's Borneo island before it disappeared on Saturday from radar screens four minutes after takeoff.
Search teams and fishermen had retrieved some debris and a section of an emergency chute believed to come from the jet.
At the time of the crash, local fishermen spoke of hearing a thunderous explosion. When they reached the area, they discovered pieces of wreckage from the airliner.
"The plane fell like lightning into the sea and exploded in the water," one fisherman told the BBC’s Indonesian service. "It was pretty close to us, the shards of a kind of plywood almost hit my ship."
Passengers' relatives and next of kin gathered at Jakarta and Pontianak airports, many of them in tears.
Among those waiting at Pontianak Airport was father-of-three Yaman Zai, who had moved there from Jakarta for work last year. His wife and children, who had remained in Jakarta, were on the flight to meet him for a holiday, having not seen him for nearly a year because of the Covid lockdown.
“They are my wife and three children, including my newly born baby”, he told the local tribunnews.com. “My last contact was around 13:30 which my wife responded that the kids were so excited."
He said he had arrived at the airport well in time for the flight's arrival and then grown worried when there was no news of the plane landing. Eventually he saw TV reports that the plane had had gone missing.
“Did I kill my family?” he asked. “I sent them here to get fun."
Indonesia, the world's largest archipelago nation, has a chequered record on transport safety, with numerous air and sea accidents over the years blamed on aging infrastructure and poorly enforced safety rules. In October 2018, a Boeing 737 MAX 8 jet operated by Lion Air also crashed taking off from Jakarta, killing all 189 people on board.
The plane involved in Saturday's crash was a Boeing 737-500 belonging to the Sriwijaya Air airline, a local discount carrier that flies to dozens of domestic and regional destinations. After being delayed for an hour because of heavy rain, it took off at 2.36pm local time but then lost control with the airport control just four minutes later.
Air traffic control officials said that seconds before the plane disappeared, they had asked the pilot why it was heading northwest instead of on its expected flight path. A post on the Twitter feed of tracking service Flightradar24 said that Flight SJ182 "lost more than 10,000 feet of altitude in less than one minute, about 4 minutes after departure from Jakarta".
Bambang Suryo Aji, the Indonesian National Search and Rescue Agency's deputy head of operations, said no radio beacon signal had been detected from the plane.
He said his agency was investigating why its emergency locator transmitter was not transmitting a signal that could confirm whether it had crashed.
The Boeing 737-500 involved in Saturday's incident was a 27-year-old model. It does not have the automated flight-control system that played a role in both the Lion Air crash in Indonesia in 2018, and another crash of a 737 MAX 8 jet in Ethiopia five months later.
Those two crashes led to grounding worldwide of the Boeing MAX 8 fleet for 20 months. Sriwijaya Air, which was founded in 2003, has had a solid safety record until now. Flight experts said it was not unusual for 27-year-old planes to still be in use.
But the crash may still raise fresh questions about the safety record of airlines in Indonesia, which saw another major air disaster in 2014, when an AirAsia aircraft crashed en route to Singapore, killing 162 people. Between 2007 and 2018, Indonesian airlines were subject to an EU flight ban, which was lifted after safety standards were deemed to have improved.