Sriwijaya Air 737 crash: What do we know so far?

The aviation industry was shaken over the weekend following the loss of an Indonesian airliner. Key.Aero reviews what is known about the flight, aircraft and airline involved

On Saturday (January 9) an Indonesian Boeing 737 crashed into the Java Sea after taking off from Jakarta/Soekarno-Hatta airport. 

The Sriwijaya Air aircraft, PK-CLC (c/n 27323) was a nearly 27-year-old -500 example that had been in the carrier’s fleet since May 2012. 

Seen here in 2017, the aircraft PK-CLC (c/n 27323), is a Boeing 737-500 series example. Flickr Commons/Ikko Haidar Farozy

Divers have now located the crash site and are yet to recover the aircraft black box flight recorders but are prioritising the victims. 

The airline confirmed on Saturday that there were 56 passengers and six crew on board the aircraft. 

The flight 

The service – SJ182/SJY182 – was a connection between the Indonesian capital and Supadio International Airport near Pontianak which was scheduled to take just over an hour and cover around 450 miles. 

SJ182's flight path takes the aircraft out over the Java Sea. Great Circle Mapper

The aircraft took off from runway 25R at 2.36pm local time and had been cleared to climb to FL290 by air traffic control as it passed 1,700ft.  

Source: Flightradar24

Departure control subsequently noticed that the jet was not on its assigned heading of 075 degrees but instead had made a left turn and was tracking northwest bound. The controller queried the crew at 2.40pm but received no reply. 

Source: Flightradar24

According to ADSB data from Flightradar24, SJ182 reached a maximum altitude of 10,900ft at 2.40.06pm. Over the next 21 seconds, the jet entered a steep descent and the last data from the jet displayed the aircraft at 250ft. 

The aircraft 

Lima Charlie was a -500 series variant of the popular Boeing 737 family of aircraft. Produced between 1981 and 2000, the type was the second-generation version dubbed the Classic. 

Again seen here in 2017, PK-CLC is the shortest version of the Classic 737. Flickr Commons/Ikko Haidar Farozy

The variant was re-engined with high bypass ratio CFM International CFM56 powerplants which offered improved fuel economy. In the cockpit, upgraded avionics were added which featured the optional electronic flight instrumentation system (EFIS). 

The wings were also improved and extended around 23cm at each tip, while the leading- and trailing-edge flaps were adjusted. 

Sriwijaya Air’s aircraft first flew on May 13, 1994, at Renton Municipal Airport and was delivered to Houston-based Continental Air Lines on May 31 as N27610. 

Seen here in May 2008 as N27610, the jet would would go on to recieve a winglet retrofit two months later. Flickr Commons/Alan Brown Photography

In March 2007, the operator – together with Aviation Partner Boeing (APB) – launched the retrofit of the blended winglet technology which added the drag reducing device to the wings of Classic 737s. In July the following year, the aircraft received this upgrade.  

Following the 2010 merger between United Airlines and Continental, the jet was transferred to the Chicago carrier’s fleet on October 1, 2010.  

On May 15, 2012, Sriwijaya Air accepted delivery of the jet which was re-registered on the Indonesian aircraft registry as PK-CLC. The airline also added six additional economy seats to take the total capacity of the narrowbody up to 120. 

Jefferson Irwin Jauwena, the airlines chief executive, told reporters that the take-off of the accident flight was delayed by 30 minutes due to heavy rain and that the aircraft itself was in good condition prior to departure. 

The airline 

Sriwijaya Air was founded in 2003 and is the country's third-largest carrier behind Lion Air and Garuda Indonesia. 

With an 18-strong all-Boeing 737 fleet comprising five -500s, 11 -800s and two -900s, the Jakarta-based airline’s roster has an average age of 17.4 years. The operator also has a subsidiary called NAM Air which was founded in 2013 and acts as a feeder carrier to its mainline parent. 

The 737-800 is the largest component of Sriwijaya Air's fleet with 11 in service. Aviation Image Network/Bailey

The crash of SJ182 adds to the airline’s already troubled safety record, which includes the loss of four other Boeing 737s since 2008, most of which have occurred during landing and have been non-fatal. 

The incidents – which occurred in 2008, 2011, 2012 and 2017 – involved -200, -300, -400 and -300 variants, respectively. 

The airline was included on the European Union’s list of banned air carriers for more than a decade between July 2007 and June 2018. 

Search teams have found the aircraft wreckage about 12 miles north of the airport where the water depth is approximately 15 to 16 metres.  

Indonesia's National Transportation Safety Committee (KNKT) has opened an investigation. Singapore has offered its assistance in the search for the black boxes while the US National Transportation Safety Board (NTSB) has appointed an investigator to assist the probe but according to Bloomberg, is awaiting further information before it determines whether to send a team. 

On Saturday, Boeing issued a statement saying it was closely monitoring the situation: “We are aware of media reports from Jakarta regarding Sriwijaya Air flight SJ182. Our thoughts are with the crew, passengers, and their families. We are in contact with our airline customer and stand ready to support them during this difficult time.” 

The cause of the crash is not known, investigators will be working to determine this over the coming months.