Sriwijaya Air's recovered cockpit voice recorder contains key to crash mystery

The Boeing 737-500, operating Flight SJ182, crashed in the Java Sea shortly after takeoff on January 9, killing all 62 people onboard

Sriwijaya Air's recovered cockpit voice recorder contains key to crash mystery
The CVR of the crashed Sriwijaya Air Flight SJ182 recovered. Image courtesy: Twitter/@KNKT_RI

The cockpit voice recorder (CVR) of the ill-fated Sriwijaya Air jet, which crashed in the Java Sea shortly after takeoff on January 9, has been recovered. The crash had killed all 62 people onboard. 

Indonesia's Transport Minister Budi Karya Sumadi revealed that Navy divers were able to retrieve the CVR on March 30, according to a Sky News report. The black box of the plane, including the casing and beacon of the CVR, was found within a few days of the crash, but it took three months to recover the memory unit in relatively shallow but muddy waters that at times generated strong currents, Reuters reported. 

The CVR was handed over to the National Transportation Safety Committee (KNKT), which is overseeing the investigation into the crash. The CVR, if undamaged, could reveal valuable information that could help investigators to ascertain the exact reason for the crash and also give an idea of what the pilots were doing to regain control of the aircraft. 

The Boeing 737-500, operating Flight SJ182 and bearing the registration number PK-CLC, was on its way from Jakarta's Soekarno-Hatta International Airport to Pontianak in West Kalimantan province. It had climbed to 10,900 feet within four minutes but then started falling amid heavy rainfall. The plane lost 10,000 feet in less than one minute, according to flight-tracking service Flightradar24. It then went off the radar. The plane had lost contact at 2.40 pm local time 11 nautical miles (around 20 km) north of the Soekarno-Hatta International Airport, CNN reported.

An investigator of the KNKT said that considering that the debris was not scattered in a wide area, the plane possibly broke apart after hitting the waters.

According to a fisherman, there was a very loud explosion, which seemed like a bomb or a giant thunder. This was followed by a large wave about two metres high in the sea. Another witness agreed that it seemed like a bomb on water, adding that shards of a kind of plywood almost hit their ship.

Also read -- Indonesia air crash: Black box recovered, mystery behind disaster may soon be solved

Preliminary investigation suggested that the plane's left engine throttle moved backwards on its own while on autopilot, reducing the engine's power. The nearly 27-year-old plane was out of service for nine months as a result of flight cutbacks in the wake of the Covid-19 pandemic before clearing safety checks for resuming commercial flights in December 2020. 

Since the crash, search and rescue teams have recovered plane debris and human remains in the area between Lancang and Laki islands, known as the Thousands Islands chain, about 20 miles (32.18 km) northwest of the Indonesian capital Jakarta. The CVR is believed to have broken away from the other parts of the device on impact, the Sky News report said. According to the Indonesian Navy, the voice recorder was buried under three feet of mud at a depth of 75 feet. 

The ill-fated Boeing 737-500 operated by Sriwijaya Air. Image courtesy: Twitter/@flightradar24/Panji Anggoro

KNKT Chairman Soerjanto Tjahjono said that it would now take at least a week to clean and dry the CVR and download the data contained in it. "Without the voice recorder, it would be difficult to determine the cause of the plane crash," Tjahjono said.

Around 2,600 personnel were deployed in the search operation apart from dozens of boats and helicopters, according to AFP. Over 50 ships and 13 aircraft had also been mobilised. The operation was jointly conducted by Indonesia's national search and rescue agency Basarnas, the Indonesian Navy, police, Coast Guard and transportation ministry. However, most retrieval efforts ended two weeks after the crash and only limited search teams had been used since. 

Air travel in Indonesia has grown since the demise of the Suharto dictatorship in the 1990s. The Sriwijaya Air crash adds to Indonesia's disappointing record in terms of transportation accidents. Indonesia, which is the world's largest archipelago nation, houses more than 260 million people. Transportation accidents on land, air and sea have continued to happen as a result of overcrowding on ferries, age-old infrastructure and poorly-enforced safety standards, according to an AP report. 

Also read -- Indonesia air crash: Plane possibly burst after hitting sea; hunt for black boxes on

This comes after the Lion Air crash in October 2018, which saw a Boeing 737 Max crashing into the Java Sea 13 minutes after takeoff, killing all 189 people onboard. It was the deadliest involving Boeing 737 planes and the second deadliest in Indonesia after the Garuda Indonesia crash in 1997 that killed 234 people. In December 2014, an AirAsia flight from Surabaya to Singapore crashed into the sea, killing 162 people. The Sriwijaya crash makes it eight air crashes in Indonesia in the new millennium, with a death toll of 960.  

The US had banned Indonesia carriers in 2007. It reversed the decision in 2016, saying that compliance with international aviation standards had improved. In 2017, the European Union (EU) banned all 51 Indonesian carriers after a Garuda Indonesia plane overshot the runway in Yogyakarta, killing 21 out of the 140 people onboard. The EU ban was lifted in 2018. 

According to Reuters, the Boeing 737-500 is much older than the problem-plagued B737 Max and is two generations of development before the Max.