Indonesian Sriwijaya Air plane crashes after take-off with 62 aboard

Rescue agency Basarnas said in a statement it would send a team to the Thousand Islands area to help in the search for victims "after the crash of Sriwijaya Air SJ 182".

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All those on board were Indonesian, Indonesia's transport safety committee said.

On Sunday, Indonesia's military chief said divers had spotted parts of the wreckage of a Boeing 737-500 at a depth of 23m in the Java Sea.

"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. "We are sure that is the point where the plane crashed."

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

"Hopefully until this afternoon the current conditions and the view under the sea are still good so that we can continue the search," he said.

The break in the search for Sriwijaya Air flight SJ 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.

Indonesian airline Sriwijaya Air's chief executive, Jefferson Irwin Jauwena, told a news conference that the plane had been in good condition before the flight.

The nearly 27-year-old Boeing 737-500 was much older than Boeing's problem-plagued 737 MAX model, one of which crashed off Jakarta in late 2018, killing all 189 people aboard the Lion Air flight. Older 737 models are widely flown and do not have the system implicated in the MAX safety crisis.

A Boeing spokeswoman said, "We are aware of media reports from Jakarta, and are closely monitoring the situation. We are working to gather more information."

Reliable tracking service Flightradar24 said the Boeing jet took off at 2.36pm local time and climbed to reach 10,900ft within four minutes. It then began a steep descent and stopped transmitting data 21 seconds later.

A transport ministry spokeswoman said air traffic control at Soekarno-Hatta International Airport had asked the pilot why the plane was heading northwest instead of on its expected flight path just seconds before it disappeared.

There were no immediate clues on what may have caused the sudden descent and safety experts stress most air accidents are caused by a cocktail of factors that can take months to establish.

FISHERMEN HEARD "BIG EXPLOSION"

Fisherman Solihin, who like many Indonesians goes by one name, told CNA that he was on a fishing vessel with his boss and two colleagues near Lancang island when he suddenly heard a big explosion at around 2.30pm local time on Saturday. 

“I was pulling our fishing trap when I saw something falling very quickly from the sky in front of me.

"It wasn’t too far from our spot, then there was a big explosion. It exploded in the water,” he said. 

His boss Hendrik, who also goes by one name, said he was initially unsure what might have happened. 

“I was shocked. I thought it was a bomb or an airplane. We couldn’t really see. But not too long after, there was oil spill and debris. 

“So I thought it must have been a plane.” 

They decided to return to shore and went to the local police station to report the incident.

SUSPECTED PASSENGER BELONGINGS, BODY PARTS FOUND

Indonesian television channels showed pictures of suspected wreckage.

READ: More debris found as Indonesian authorities race against time to search for missing Sriwijaya Air plane

Jakarta police spokesman Yusri Yunus told CNA that as of Sunday morning, they have sent two bags to the disaster victim identification team.

One bag contains what they suspect to be passenger belongings, while another contains body parts, he said.

“We urge close kin to come forward with DNA or other material so we can match and do an antemortem and postmortem investigation.”

Distraught relatives waited at Pontianak, around 740km from Jakarta.

READ: 'Hoping for a miracle' - Anxious wait for friends and families after Sriwijaya Air plane goes missing in Indonesia​​​​​​​

Yaman Zai, a father of three children who were aboard the plane with their mother, said that he was at the airport in Pontianak waiting for them, when he heard the news.

"I will never meet her again," he said, holding up a photo of his oldest daughter.

Indonesia's KNKT safety agency was expected to launch an immediate investigation. The US National Safety Transportation Board will automatically be part of the probe, since the plane was designed and built in the United States.

Founded in 2003, Jakarta-based Sriwijaya Air group flies largely within Indonesia. The airline has a solid safety record until now, with no onboard casualties in four incidents recorded on the Aviation Safety Network database.

INDONESIA'S PATCHY SAFETY RECORD

The Boeing 737 is the world's most-sold family of aircraft and has undergone several makeovers since it entered service in 1968.

The 737-500 is two generations of development before the most recent 737 MAX, which has been embroiled in a worldwide safety crisis following crashes in Indonesia and Ethiopia. It does not use the software system implicated in those crashes.

Nonetheless, experts say planes such as Sriwijaya's leased 737-500 are being phased out for newer fuel-saving models. Civil jets typically have an economic life of 25 years, meaning they become too expensive to keep flying beyond that compared to younger models, but they are built to last longer.

Indonesia itself has a patchy air safety record.

READ: Sriwijaya Air crash places Indonesia's aviation safety under fresh spotlight

In 2007, the European Union banned all Indonesian airlines following a series of crashes and reports of deteriorating oversight and maintenance since deregulation in the late 1990s. The restrictions were fully lifted in 2018.

Between 2007 and 2016, the US Federal Aviation Administration lowered its Indonesia safety evaluation to Category 2, meaning its regulatory system was inadequate.

Indonesian officials say they have worked hard to bring safety up to international standards.

Additional reporting by Kiki Siregar