Indonesian authorities said on Sunday that they have determined the site where a plane with 62 people on board crashed into the Java Sea shortly after take-off.

National Search and Rescue Agency head Bagus Puruhito said officials believe they have located the Boeing 737-500’s flight data recorder and cockpit voice recorder – the so-called black boxes – because emergency signals transmitted by the devices were detected by a navy ship’s sonar system.

“We have determined the position of the plane’s black boxes from two signals emitted by the devices,” military chief Hadi Tjahjanto said. “Hopefully we can lift the black boxes in short time to determine the cause of the crash.”

Earlier on Sunday, search and rescue operations resulted in parts of the plane being found in the sea at a depth of 75ft (23m), leading rescuers to continue searching the area.

“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,” Mr Tjahjanto said. “We are sure that is the point where the plane crashed.”

He said objects found included broken pieces of fuselage with aircraft registration parts.

Earlier, rescuers retrieved body parts, pieces of children’s clothing and scraps of metal from the surface.

The breakthrough in the search for Sriwijaya Air Flight 182 came after the navy ship’s sonar equipment detected a signal from the aircraft at a location that fitted with the co-ordinates from the last contact made by the pilots before the plane disappeared on Saturday afternoon, Mr Tjahjanto said.

Indonesia Plane Crash
Investigators inspect clothing recovered from the Java Sea, where Sriwijaya Air Flight 182 crashed (Tatan Syuflana/AP)

The plane was en route from Jakarta to Pontianak, the capital of West Kalimantan province on Indonesia’s Borneo island, on a flight that was expected to take around 90 minutes.

The cause of the crash is still unclear and there has been no sign of survivors.

Indonesian President Joko Widodo said: “I represent the government and all Indonesians in expressing my deep condolences for this tragedy.

“We are doing our best to save the victims. We pray together so that the victims can be found.”

He added that he has asked the National Transport Safety Committee to carry out an investigation.

Fishermen in the area between Lancang and Laki islands, part of an archipelago around Thousand Islands north of Jakarta’s coast, reported hearing an explosion at about 2.30pm on Saturday.

“We heard something explode – we thought it was a bomb or a tsunami since after that we saw a big splash from the water,” Solihin, who goes by one name, said by phone.

“It was raining heavily and the weather was so bad, so it was difficult to see around clearly, but we saw the splash and a big wave after the loud sound. We were very shocked and saw the plane debris and the fuel around our boat.”

Indonesia Plane Crash
Indonesian navy divers recover part of the plane from the water (Achmad Ibrahim/AP)

Transportation Minister Budi Karya Sumadi said the flight was delayed for an hour before it took off at 2.36pm. It disappeared from radar four minutes later, after the pilot contacted air traffic control to ascend to an altitude of 29,000ft (8,839m), he said.

There were 62 people on board, all of them Indonesian nationals, including three babies and seven other children. The plane was carrying 50 passengers, six working crew members and six other crew for another flight.

“Our thoughts are with the crew, passengers, and their families,” Boeing said in a statement. “We are in contact with our airline customer and stand ready to support them during this difficult time.”

Authorities established two crisis centres – one at Soekarno-Hatta International Airport, where the plane departed from, and one at port. Families gathered to wait for news about their loved ones.

On social media, people began circulating the flight manifesto with photos and videos of those who were listed as passengers. One video shows a woman with her children waving goodbye while walking through the airport.

Sriwijaya Air president director Jefferson Irwin Jauwena said the plane, which was 26 years old and previously used by airlines in the United States, was airworthy. He told reporters on Saturday that it had flown to Pontianak and Pangkal Pinang city earlier in the day.

He added that the flight was delayed due to bad weather, not because of any mechanical problems.

Indonesia Plane Crash
Indonesian navy and police personnel carry a tarpaulin containing debris recovered from the waters off Java Island around where a Sriwijaya Air passenger jet (Tatan Syuflana/AP)

Indonesia, the world’s largest archipelago nation, with more than 260 million people, has been plagued by transport accidents on land, sea and air because of overcrowding on ferries, ageing infrastructure and poorly enforced safety standards.

In October 2018, a Boeing 737 Max 8 jet operated by Lion Air plunged into the Java Sea just minutes after taking off from Jakarta, killing all 189 people on board.

The plane involved in Saturday’s disaster did not have the automated flight-control system that played a role in the Lion Air crash and another crash of a 737 Max 8 jet in Ethiopia five months later, leading to the grounding of the Max 8 for 20 months.

The Lion Air crash was Indonesia’s worst airline disaster since 1997, when 234 people were killed on a Garuda airlines flight near Medan on Sumatra island.

In December 2014, an AirAsia flight from the Indonesian city of Surabaya to Singapore plunged into the sea, killing 162 people.

Sriwijaya Air has had only minor incidents in the past, though a farmer was killed in 2008 when a plane went off the runway while landing due to a hydraulic issue.

The US banned Indonesian carriers from operating in the country in 2007, but reversed the decision in 2016, citing improvements in compliance with international aviation standards. The European Union has previously had similar bans, lifting them in June 2018.