It is feared 62 staff and passengers perished after a Sriwijaya Boeing 737-500 crashed after takeoff from Jakarta on Saturday. Credit; Sriwijaya Air.

Authorities have pinpointed the location of the cockpit voice and flight data recorders from a crashed Indonesian jet, items crucial to understanding what happened to the aircraft that went down on Saturday with 62 people on board, Al Jazeera reported.

According to media reports, Indonesian divers also located parts of the wreckage of a Boeing 737-500 in the Java Sea as rescuers pulled out body parts, pieces of clothing and scraps of metal from the waters where Sriwijaya Air flight SJ182 is believed to have crashed.

In an eerily familiar crash scenario related to previous Boeing 737 accidents, the aircraft suddenly disappeared from radar screens after takeoff from Indonesia’s capital Jakarta and plunged into the sea, CBC News reported.

Transportation Minister Budi Karya Sumadi said Flight SJ182 was delayed for an hour before it took off at 2:36 p.m. local time.

It vanished from radar just four minutes later, after the pilot contacted air traffic control to ascend to an altitude of 29,000 feet (8,839 metres), CBC reported.

The airline said in a statement that the plane was on an estimated 90-minute flight from Jakarta to Pontianak, the capital of West Kalimantan province on Indonesia’s Borneo island.

The plane was carrying 50 passengers and 12 crew members, all Indonesian nationals, including six extra crew for another trip, CBC reported.

The plane involved in Saturday’s incident did not have MCAS, 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.

Sumadi said a dozen vessels, including four warships, were deployed in a search-and-rescue operation centred between Lancang island and Laki island, part of the Thousand Islands chain just north of Jakarta, CBC reported.

Bambang Suryo Aji, the National Search and Rescue Agency’s deputy head of operations and preparedness, said rescuers collected plane debris, clothes and body parts that were found by fishermen.

Divers recovered parts of the plane about 23 metres (75 feet) below the water’s surface.

Local Indonesian fisherman hold up debris from a suspected Boeing 737 crash. Credit: Mulyono/Naki.

The break in the search for Sriwijaya Air flight SJ182 came after sonar equipment on a navy ship detected a signal from the 27-year-old plane at a location that fit the coordinates from the last contact made by the pilots.

Authorities said Monday that their efforts to recover bodies, the Cockpit Voice Recorder (CVR) and Flight Data Recorder (FDR) were hampered by debris in the water.

“We have two spots that highly suspected as a location of two black boxes. But unfortunately there is a lot of debris around those spots,” Indonesia Navy Commander Admiral Yudo Margono said.

Margono said a diving team is working to clear out debris, and hope to recover the devices “soon.”

A command post set up at the Kramat Jati Police Hospital in Jakarta to identify the crash victims and search for family members was working to identify the remains.

A captain of one of the search-and-rescue ships who goes by a single name, Eko, said that fishermen found cables and pieces of metal in the water.

“The fishermen told us that they found them shortly after they heard an explosion like the sound of thunder,” Eko was quoted by TVOne as saying, adding that aviation fuel was found in the location where the fishermen found the debris, CBC reported.

Tracking service Flightradar24 said on its Twitter feed that Flight SJ182 lost more than 10,000 feet (3,048 metres) of altitude in less than a minute, about four minutes after takeoff.

Chicago-based Boeing said on its Twitter feed that it was aware of the incident. It said it was closely monitoring the situation and “working to gather more information.”

The twin-engine, single aisle Boeing 737 is one of the world’s most popular planes for short and medium-haul flights. The 737-500 is a shorter version of the widely used 737 model, CBC reported.

Sriwijaya began operations in 2003 and flies to more than 50 destinations in Indonesia and a handful of nearby countries, according to its website. Its fleet includes a variety of 737 variants, as well as the regional ATR 72 twin-engine turboprop.

The twin-engine, single aisle Boeing 737 is one of the world’s most popular planes for short and medium-haul flights. The 737-500 is a shorter version of the widely used 737 model,. Courtesy: Sriwijaya AIr.

The airline has had a solid safety record until now, with no onboard casualties in four incidents recorded on the Aviation Safety Network database.

Relatives of the passengers have been waiting anxiously at the airport in Pontianak, as well as at Jakarta’s Soekarno-Hatta International Airport.

“I have four family members on the flight – my wife and my three children,” Yaman Zai told reporters through tears, BBC News reported.

“[My wife] sent me a picture of the baby today … How could my heart not be torn into pieces?”

Among those missing and feared dead are a family of five, according to an aunt of the family who spoke to CNN.

The family released a statement saying that the father, 26-year-old Rizki Wahyudi who worked for the Indonesian Forestry Commission, his 26-year-old wife Indah Halimah Putri, their 7-month-old son, as well as his mother and cousin, were on the flight that crashed.

According to registration details, the plane is a 27-year-old Boeing 737-500.

It was in good condition, Sriwijaya Air chief executive Jefferson Irwin Jauwena told reporters. Take-off had been delayed for 30 minutes due to heavy rain, he said.

Indonesia, though, has a relatively poor record on aviation safety.

For more than a decade carriers from the region were banned from flying into the EU, BBC News reported.

Until recently, the perception had been that standards were improving, and in 2018 all Indonesian airlines were removed from the EU’s blacklist.

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

Fisherman off the coast of Jakarta retrieve parts of the missing Boeing 737 airliner. They reported hearing a loud explosion in the area. Credit: AFP.

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

Fishermen in the area around the Thousand Islands, a chain of islands north of Jakarta’s coast, reported hearing an explosion about 2:30pm (07:30 GMT) on Saturday.

“We heard something explode; we thought it was a bomb or a tsunami since after that we saw the big splash from the water,” fisherman Solihin, who goes by one name, told The Associated Press.

“It was raining heavily and the weather was so bad. So, it is difficult to see around clearly. But we can see the splash and a big wave after the sounds. We were very shocked and directly saw the plane debris and the fuel around our boat.”

Meanwhile, National Transportation Safety Committee teams have begun an investigation into the cause of the crash.

“We sent two investigators with Indonesian Search and Rescue Agency to the sea to do a location survey. We need to find more information on the location, for example to determine what gear we are going to use regarding the underwater terrain we have,” Suryanto Cahyono told CNN.

Investigators have also been sent to Air Traffic Control at the airport, the Meteorology Climatology and Geophysical Agency, and to Sriwijaya Airlines to gather information.

National Transportation Safety Board USA has assigned Michael Hauff, their accredited aircraft crash expert, to fly to Indonesia to investigate.

“This is not even the model before the Max, it has been in service for 30 years so it’s unlikely to be a design fault,” said Richard Aboulafia, an aviation analyst at Teal Group Corp.

“Thousands of these planes have been built and production ended over 20 years ago, so something would have been discovered by now.”

Investigators believe that the plane was fully intact when it crashed into the sea owing to the fact that debris from the wreckage has so far been located only in a single, concentrated area.

Sources: CBC, Al Jazeera, Associated Press, BBC News, CNN World, Bloomberg