By Louise Wattin

Investigators in Indonesia are hopeful of discovering the reason why a Boeing 737 with 62 people on board crashed into the sea, after divers yesterday located the plane’s black boxes.

The Sriwijaya Air flight took off from the capital, Jakarta, on Saturday afternoon but soon went into a deep dive into the Java Sea.

There was no sign of any survivors among the 50 passengers and 12 crew members. Ten of the passengers were children.

After almost a day of searching by helicopters and warships, rescuers identified the location of the crash site and the plane’s flight recorder and cockpit voice recorder – otherwise known as the black boxes. A navy ship had detected emergency signals sent out by the boxes. Hadi Tjahjanto, Indonesia’s armed forces commander, said they hoped they could lift the black boxes out soon.

Rescuers had earlier found parts of the plane at a depth of 23 metres in the Java Sea, as well as debris, body parts, life jackets and children’s clothing.

The area determined to be the crash site fits the coordinates of the plane’s last-known contact.

Fishermen in the area around Thousand Islands, north of Jakarta’s coast, had reported hearing something explode.

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

“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.”

All those on board were Indonesian, authorities said. The passengers included Beben Sofian (59), and her husband Dan Razanah (58). “They took a selfie and sent it to their kids before taking off,” the couple’s nephew Hendra said.

Any hope of finding survivors was fast fading. The search and rescue agency said yesterday afternoon that it had so far filled five body bags with human remains and debris.

The plane operated by Sriwijaya Air, a low-cost airline, had taken off at 2.36pm on Saturday for a 90-minute flight to Pontianak, the capital of Indonesia’s West Kalimantan province on Borneo island.

It disappeared from radar minutes later, after the pilot contacted air-traffic control for permission to ascend to 29,000 feet, Transportation Minister Budi Karya Sumadi, said.

The plane had taken off late because of bad weather, according to the head of Sriwijaya Air, Jefferson Irwin Jauwena.

He said the Boeing 737-500 plane, which was 26 years old and previously used by airlines in the US, was airworthy, and had flown to two other cities on the same day.

For more than a decade from 2007, the US and EU banned all Indonesian airlines from operating within their borders following a series of crashes and reports of poor oversight and maintenance.

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.