Sriwijaya Air Flight 182

Sriwijaya Air Flight 182 was a scheduled domestic passenger flight from Jakarta to Pontianak, Indonesia. Five minutes after departing from Soekarno–Hatta International Airport on 9 January 2021, the Boeing 737-524 flying the route experienced an upset and crashed into the Java Sea off the Thousand Islands, killing all 62 people aboard.
A search of the area recovered wreckage, human remains, and items of clothing, but no survivors. On 21 January, the search for survivors was halted and all are presumed dead. The flight data recorder (FDR) was recovered on 12 January, whereas the data storage module of the cockpit voice recorder was recovered nearly three months after the crash.
During the search, the National Transportation Safety Committee (NTSC) used the engines and available data from Flightradar24, and hypothesised that the plane had been still responsive upon impact, where it had ruptured. Investigation was announced to focus on the aircraft's autothrottle due to its previous malfunctions.
Flight timeline.
Prior to Flight 182, the aircraft arrived at Soekarno–Hatta International Airport in Tangerang, Banten at 12:11 PM from Pangkal Pinang Depati Amir Airport. The aircraft was scheduled to take off at 13:25 WIB (06:25 UTC), and was scheduled to arrive at Supadio International Airport in Pontianak, West Kalimantan, at 15:00 WIB (08:00 UTC). After pushing back from the airport's Terminal 2D Gate B1, the aircraft took off from Runway 25R at 14:36 local time (07:36 UTC). The flight took off amid heavy monsoon rain, following a bad weather delay. Due to the significant delay, it was expected to land in Pontianak at 15:50 WIB (08:50 UTC).
Flight 182 was climbing to when it abruptly dived, then it suddenly turned to the right. An air traffic controller (ATC) noticed this and asked the pilots what was happening on board, but received no response. According to AirNav Radarbox flight data, the aircraft reported a rapid drop in altitude during the climb phase from to at 07:40 UTC. Flightradar24 reported that four minutes after takeoff, the aircraft dropped by in less than a minute. The flight tracker also noted that the aircraft's last recorded altitude was 250 feet (76 m) at 07:40:27 UTC. According to provided flight data, the airplane experienced a drop of in just six seconds between 07:40:08 and 07:40:14 UTC. It was followed by a drop of in two seconds, in four seconds, and in its last seven seconds. During the fall, the aircraft rapidly changed speed, decreasing and increasing in seconds. Its last contact with ATC was at 14:40 WIB (07:40 UTC) in a location between Laki Island and Lancang Island. The aircraft crashed into the Java Sea near Laki Island and from Soekarno–Hatta International Airport. According to the ATC, there was no distress call during the flight. Indonesian transport officials also stated that the aircraft failed to follow ATC instructions.
Aircraft.
The aircraft involved was a Boeing 737-524, registered as PK-CLC ( 27323/Line no.2616). It was equipped with two CFMI CFM56-3B1 engines. At the time of the accident, the aircraft had accumulated 62,983 hours and 40,383 cycles.
The aircraft was manufactured in 1994, and had its maiden flight on 13 May 1994. It was first delivered to Continental Airlines on 31 May 1994 under the registration N27610. The aircraft was transferred to United Airlines in 2010 after Continental and United merged. On 15 May 2012, the aircraft was sold to Sriwijaya Air. It was the first of a total of fifteen 737-500s received by Sriwijaya Air in 2012 to replace their 737-200s. Sriwijaya Air named the aircraft "Citra". Between 23 March and 23 October 2020, the aircraft was stored at Surabaya Juanda International Airport for repair. The Ministry of Transportation stated that it inspected the aircraft on 14 December 2020 and issued a new certificate of airworthiness on 17 December 2020. It resumed service on 19 December 2020.
Passengers and crew.
There were 62 people on board, of which 50 were revenue passengers (43 adults and 7 children). Of the remaining 12 crew members, six were operating crew on the flight, while the other six were deadheading as passengers. The majority of the passengers were residents from West Kalimantan. Among the passengers was Mulyadi Tamsir, a politician from the People's Conscience Party (Hanura).
The active crew consisted of Captain Afwan, First Officer Diego Mamahit and four flight attendants. Afwan was a former pilot in the Indonesian Air Force.
The six deadheading crew and several revenue passengers had transferred to Flight 182 from an earlier NAM Air flight that did not operate.
The Associated Press, BBC News, "HuffPost", "The New York Times", "The Wall Street Journal", and other media have reported that all people on board had been killed. At least 58 victims, including the captain, have been identified by the police.
Search.
The first report of the crash was made at 14:30 WIB (07:30 UTC), in which a fisherman said that an aircraft had crashed and exploded in the sea.
The head of the Indonesian National Search and Rescue Agency (), reported that the crash site was located from Soekarno-Hatta International Airport.
Personnel from a vessel provided by the Ministry of Transportation reported that body parts, fragments of clothing, electronics, personal belongings and wreckage had been recovered from the sea in waters near the Thousand Islands, with aviation fuel also reported around the location. The water near the crash site has a depth of around .
BASARNAS immediately deployed personnel to the crash site while the Indonesian National Police and the Ministry of Transportation set up crisis centres in Port of Tanjung Priok and Soekarno–Hatta International Airport. The Indonesian Navy deployed a number of vessels for the search and rescue operations, in addition to helicopters and KOPASKA (frogman) personnel.
The Indonesian government requested assistance from the South Korean government with the search. Through the Korea - Indonesia Marine Technology Cooperation Research Center (MTCRC), the South Korean Ministry of Oceans and Fisheries deployed a research vessel equipped with a detector to Indonesia. At least 15 personnel from MTCRC were also sent. The Singaporean government also offered to provide assistance in the search which the Indonesian government later accepted.
On 10 January, the Indonesian Navy announced that the exact coordinates of the crash site had been pinpointed.
Recovery.
Rescuers managed to recover a life vest, pieces from the aircraft's fuselage, and a destroyed wheel rim of the Boeing 737. Most of the wreckage was found at a depth of .
On the night of 9 January, an emergency slide of the aircraft was recovered from the waters near Lancang Island, Thousand Islands. The scattered debris and the small pieces of the wreckage indicated a high-speed impact. Much more wreckage was found over the next few days.
On 10 January, the National Transportation Safety Committee (NTSC) reported that they had located the position of the cockpit voice recorder and the flight data recorder, but after the flight data recorder was retrieved at 16:00 WIB on 12 January, it was reported that beacons on both flight recorders were dislodged in the impact and the cockpit voice recorder would need to be found without the assistance from underwater guidance signals. The casing of the cockpit voice recorder was recovered on 15 January but the data storage module inside was missing. BPPT stated that the data storage module of the CVR was thought to be buried under the aircraft's wreckage. In the afternoon of 17 January, the CVR components and its casing, but without the data storage module, were handed over to the NTSC for further examination. The next day on 18 January, the search for the CVR, wreckage, and victims was extended for three more days.
On 21 January BASARNAS announced the search for victims and aircraft debris had been halted. A total of 122 pieces of debris had been recovered from the crash site, including one of the aircraft engines' turbines. As of 10 February, the search for the data storage module of the CVR was ongoing.
On 30 March, nearly 3 months after the crash, BASARNAS recovered the missing CVR component using a hopper dredger, at a depth of 14 meters, with coordinates of ; the search operation was officially ended.
Investigation.
The NTSC was immediately notified of the accident, with assistance from BASARNAS. NTSC stated that starting on 10 January 2021, just before 06:00 local time, search and rescue personnel would start searching for the aircraft's flight recorders. It added that the investigation will be assisted by the United States' National Transportation Safety Board (NTSB), with the Singaporean Transport Safety Investigation Bureau also offering assistance with the investigation. On 10 January, NTSC obtained raw data of the aircraft's flight path from radar and interviews with the air traffic controller. Investigators also retrieved the transcript of the communication between the pilots and the ATC.
A spokeswoman from the Indonesian Ministry of Transportation reported that an abnormality was noted during the flight. The aircraft departed from Jakarta's Soekarno-Hatta International Airport on a standard instrument departure. The aircraft had been cleared to climb to . During its climb, Flight 182 went off course to the northwest. ATC asked the crew about the deviation and got no response. A few seconds later, the aircraft dropped off radar.
An investigator with NTSC stated that based on the distribution of the debris, the aircraft possibly ruptured when it hit the water. Combining Flightradar24 data and the shape of the engine turbine's fan blade and turbine disc, NTSC speculated that the aircraft's engines were still operating upon impact; based on the evidence, the aircraft was still responsive at 250 feet.
There was a public concern that the aircraft was not airworthy. The Federal Aviation Administration initially had issued an Airworthiness Directive to Boeing 737-500 operators, concerning fatigue cracking on the left nacelle support overwing fitting flange fastener hole. The director of Sriwijaya Air, Jefferson Irwin Jauwena, insisted that the aircraft was airworthy. Although a 30-minute delay was noted, he insisted that the cause was bad weather, specifically heavy rain, rather than mechanical failure. In response, the NTSC said that they would be coordinating with the Meteorology, Climatology, and Geophysical Agency (BMKG) in relation to weather in the Jakarta area. However, the Ministry of Transportation later examined the aircraft's airworthiness and determined that the aircraft was safe to fly.
An Indonesian aviation expert said that the aircraft had been stored for repairs by Sriwijaya Air between 23 March and 23 October 2020, signifying good maintenance history. However, other experts speculated that the long time spent inactive may have caused deterioration and that technical problems may have developed.
On 15 January, NTSC announced that the data from the FDR have been successfully downloaded. A total of 330 parameters were being examined and analysed by investigators. A Reuters report said that the data extracted, such as flight path, speed and engine condition, were "in good condition".
The preliminary report was released on 10 February 2021.
On 12 April, the NTSC announced that all data from the CVR was successfully downloaded and included the accident flight.
Weather.
Weather data retrieved from BMKG confirmed the presence of moderate to heavy rain during takeoff with chance of thunderstorms reported. The data later showed that a high cumulonimbus cloud was present around Soekarno-Hatta International Airport with the minimum temperature of the cloud tops at , prompting speculation that the aircraft had encountered turbulence. Visibility was reported to be . Analysis by the Indonesian National Institute of Aeronautics and Space (LAPAN) showed that weather conditions were not extreme. LAPAN stated that a meso-convective system had been formed near the Java Sea at 11:00 WIB (04:00 UTC), but the system had already dissipated by the time Flight 182 took off. According to NTSC, there was no indication that there would be any significant cloud on the aircraft's flight route. NTSC confirmed, however, that the pilots had contacted Jakarta ATC to change its heading to 075 due to bad weather.
Maintenance problem.
According to "Tempo" magazine, sources close to the investigation committee revealed that the aircraft involved in the accident had a recurring autothrottle problem for at least a month. NTSC, however, stated that they did not have the maintenance data yet. According to a person familiar with the investigation, "the autothrottle was producing more thrust in one of the two jet engines" during the flight. If pilots did not set the power manually, "an aircraft could turn to the side or even make an abrupt descent". On 22 January it was revealed that a malfunction of the autothrottle system had been reported several days before the flight; the aircraft can fly without the system, however, as the pilot can set the throttles manually.
The investigation will be focused on the faulty autothrottle system, as multiple parameters from the FDR indicated that an abnormality had occurred in the system. NTSC later stated that the committee have sent 13 parts of the aircraft's component, including the aircraft's authothrottle system, to United States and United Kingdom for further examination.
The maintenance logbook of the aircraft revealed that there had been recurring problems on the Mach/Airspeed indicator and the auto-throttle system of the aircraft. The Mach/Airspeed indicator was eventually replaced on January 4, while the auto-throttle system was fixed on January 5. The FDR data, however, confirmed that the auto-throttle had malfunctioned again on January 9, the day of the accident. While the aircraft was climbing to 10,000 ft, the left engine thrust lever continued to decrease, while the thrust lever on the right engine remained in place. When the aircraft reached 10,000 ft, an aircraft upset happened. The autopilot disengaged and the aircraft rolled to the left with a bank angle of more than 45 degree. Few seconds later, the auto-throttle then disengaged.
Responses.
In the immediate aftermath of the accident, the state's insurance company Jasa Raharja announced that it would compensate the relatives of the passengers and crew members aboard Flight 182. Each next-of-kin of the deceased would receive Rp 50 million (US$). Minister of Social Affairs Tri Rismaharini announced that her ministry would give Rp 15 million (US$) for each victim for compensation.
Delegations from Indonesia's House of Representatives visited the operation centre in Tanjung Priok. They later announced that the House would hold talks with the Ministry of Transportation about the accident. They also stated that they would hold talks with BMKG, Sriwijaya Air and NTSC. The Indonesian House of Representatives will scrutinize the operation of conduct of the Indonesian Ministry of Transportation regarding supervision of airliners' compliance with the aircraft's maintenance manual. A full evaluation of every airliner in Indonesia was later ordered.
The Regent of Thousand Islands, Junaedi, stated that the government of Thousand Islands will build a monument dedicated to the victims of Flight 182 on Lancang Island. On 22 January 2021, family and loved ones of the victims were invited to spread flowers approximately where the plane had crashed. Prior to the event, the director of Sriwijaya Air expressed condolences to the victims, and invitees were asked to pray based on their own beliefs.