Adam Air Flight 574 was a scheduled domestic passenger flight operated by an Adam Air Boeing 737-400 between the Indonesian cities of Jakarta, Surabaya, and Manado that crashed into the Makassar Strait near Polewali in Sulawesi on 1 January 2007. All 102 people on board were killed, making it the deadliest aviation accident involving a 737-400. After this, Adam Air faced intense scrutiny by the Indonesian government, which launched a national investigation into the disaster. The government's final report, released on 25 March 2008, concluded that the pilots lost control of the aircraft after they became preoccupied with troubleshooting the inertial navigation system and inadvertently disconnected the autopilot. Despite a series of safety incidents, which contributed to the shutdown of Adam Air in 2008, this was the only incident resulting in fatalities during the airline's 5-year existence.
Together with the subsequent crash of Adam Air Flight 172 and several other transportation accidents, the crash contributed to the United States' downgrading of its safety rating of Indonesian aviation. This eventually led to large-scale transportation safety reforms in Indonesia. All Indonesian airlines were banned from flying into the European Union for several years after the crash. After numerous warnings by the authorities for Adam Air to implement safety regulations went unheeded, the airline was banned from flying by the Indonesian government in March 2008, and declared bankruptcy in June of the same year.
Background
Aircraft
The aircraft involved was a Boeing 737-4Q8 registered as PK-KKW with the serial number 24070 and line number 1665. The airplane first flew on 11 January 1989. Adam Air acquired the jet on 1 December 2005. Prior to service with Adam Air, the aircraft was owned by International Lease Finance Corporation and has been leased to seven airlines: Dan-Air, British Airways, GB Airways, National Jet Italia, Wells Fargo Bank Northwest (WFBN), Air One, and Jat Airways. The plane was equipped with two CFM56-3C1 engines, had around 50,000 hours flying, and was last evaluated and declared airworthy by the Indonesian transport ministry on 25 December 2005. It was due to be checked again in late January 2007. The Surabaya airport duty manager said that no technical problems with the aircraft were found prior to departure.
Pilots
In command was 47-year-old Captain Refri Agustian Widodo from Sidoarjo, Indonesia, who joined Adam Air in 2006. His co-pilot was 36-year-old First Officer Yoga Susanto from Magelang, an employee of Adam Air, who also joined the company in 2006. Captain Widodo was a seasoned veteran, having logged more than 13,300 hours of flying time. As pilot-in-command of Boeing 737 aircraft, he had more than 3,800 hours of experience. First Officer Susanto had 4,200 total flying hours and he had almost 1,000 hours logged as a Boeing 737 first officer.
Flight chronology
On 1 January 2007, at 12:59 local time (05:59 UTC), the plane departed from Juanda Airport, Surabaya, with 96 passengers (85 adults, seven children, and four infants), a 56% load factor, and 6 crew on board. The passenger list was composed mainly of Indonesian nationals with a majority of the passengers returning to Manado after New Year's Day; the foreigners were an American family of three and a German national. The two-hour flight, scheduled to arrive at Sam Ratulangi Airport, Manado, at 16:00 local time, was normal until the plane vanished from air traffic control radar screens at Makassar, South Sulawesi, with the final contact at around 15:00 local time. The last known beacon position was detected by a Singaporean satellite. The altitude of the plane was shown as 35,000 feet (10,670 m) on the radar screen.
Weather in the region was stormy; the Indonesian Bureau of Meteorology and Geophysics noted that the cloud tops were up to 30,000 feet (9,140 m) in altitude with an average wind speed of 30 knots (56 km/h) in the area. Although the Juanda Airport operator, PT Angkasa Pura I, had given the pilot the weather conditions, the plane departed as scheduled. The plane ran into crosswinds of more than 70 knots (130 km/h; 81 mph) over the Makassar Strait, west of Sulawesi, where it changed course eastward toward land before losing contact.
Problems started when the pilots noticed an anomaly in the inertial reference system (IRS). The first officer then attempted to troubleshoot, resetting his IRS unit by switching the knob on his side to Attitude (ATT) mode; this disengaged the autopilot with a 4-second autopilot disconnect tone, effectively requiring the captain to take control and fly the plane straight and level for 30 seconds as the realignment process was completed. Neither crew member noticed the autopilot was no longer engaged, and the captain did not take control. Previous maintenance issues involving the aircraft's ailerons caused the airplane to slowly roll to the right and the nose to drop. When the aircraft reached 35° right bank and increasing, a "bank angle" audible warning sounded in the cockpit.
This accident resulted from a combination of factors, including the failure of the pilots to adequately monitor the flight instruments, particularly during the final 2 minutes of the flight. Preoccupation with a malfunction of the IRS diverted both pilots' attention from the flight instruments and allowed the increasing bank angle and descent to go unnoticed. The pilots did not detect and appropriately arrest the descent soon enough to prevent loss of control.
Captain Widodo told the first officer to switch the IRS mode back to NAV, to hopefully reverse the situation. Now that the first officer's attitude indicator had returned to its normal state, First Officer Susanto could see that the aircraft was in a dangerous position, and attempted to notify the captain. When this failed, he then tried to recover the aircraft from its descent by turning the yoke to the left. Believing that the aircraft was flying straight and level, Captain Widodo then unknowingly reminded First Officer Susanto that the aircraft needed to fly straight and level to complete the IRS alignment process. The aircraft was now in a 100° right bank with a 60 nose-down attitude. First Officer Susanto successfully notified the captain of their situation. In response to the first officer telling him to pull up to stop the rapid descent towards the sea, Captain Widodo pulled back on his yoke, and the aircraft, travelling at Mach 0.926 (92.6% the speed of sound), experienced a force 3.5 times the force of gravity at a calibrated airspeed of 490 knots (well above its maximum speed) and began to break apart in-flight. All recordings stopped at 9,000 feet, presumably because the aircraft had fully broken apart.
No distress signals were sent by the aircraft.
Victims
There were 98 Indonesian and 3 American citizens on board the flight, along with one German citizen.
Search and rescue efforts
About 3,600 army and police personnel were mobilised in the search for the missing aircraft. One Boeing 737-200 surveillance plane, two infrared-equipped Fokker-50 aircraft from the Republic of Singapore Air Force, a Navy Nomad plane, and six helicopters were dispatched to aid searching for the missing plane from the air. The Indonesian sonar-equipped ship Pulau Rengat, capable of detecting underwater metallic objects, later joined the team, equipped with a remote-controlled minisubmarine. It searched the sea for five days between 3 and 8 January, without success.
Naval ships combed the Makassar Strait while military personnel went through jungles and mountains of Sulawesi. In the face of heavy rain and strong winds in the area, the search efforts, coordinated from Makassar city, were focused in the area between the coastal town of Majene and the mountainous region of Toraja. The search in the two areas was due to two signals, each carrying different emergency locator transmitter frequencies, received by a Singaporean satellite and an Indonesian military air base. The two separate locations produced on radar screens were a spot on the sea in Majene and on land in Rantepao, Tana Toraja. Searches were then expanded throughout the Island of Sulawesi; some were triggered by unknown distress signals received by a commercial Lion Air flight and an airport. A police officer at the Barru district police operational centre said that all the districts with stretches of coastline along the Makasser Strait had teams searching for the plane.
The head of the National Search and Rescue Agency told the Associated Press that he believed the aircraft was probably lost at sea. From 5 January 2007, the main focus of the search was relocated to areas south of Manado, after Manado's Sam Ratulangi Airport reported detecting a signal from the plane a day before. The rugged terrain coupled with thick and low-hanging clouds continued to hamper the search efforts, and three relatives of missing passengers who overflew part of the area on a military reconnaissance plane admitted that the chances of finding the plane were slim. Officials said that any bodies remaining in one piece was unlikely. On 14 January, at Indonesia's request, Singapore lent four towed underwater locator beacon detectors, sometimes called towed-pinger locators (TPLs), and six consultants to aid in the search. One week later, one of these TPLs, operated from the USNS Mary Sears, successfully located the black boxes. On 24 January, the British ship MN ''Endeavour'' joined the search for wreckage. The ship was operated by local mining firm PT Gema Tera Mustikawati and is usually used by oil- and gas-drilling companies to map the seabed. By then, the Indonesian government had spent an average of Rp 1 billion (about US$110,000) a day on the search.
On 10 February, search operations were officially halted by the Search and Rescue Agency, according to Transportation Minister Hatta Rajasa, finalising the legal status of both the plane and its passengers and crew. This announcement allowed the families of the victims to start the insurance claims process.
Discovery of wreckage
Unidentified submerged objects
On Monday, 8 January, three large metal objects, suspected to be wreckage, were detected by the Indonesian ship KRI Fatahillah's sonar. First Admiral Gatot Subyanto of the Indonesian Navy indicated three locations, between 3 and 6 km (1.9 and 3.7 mi; 1.6 and 3.2 nmi) apart, off Mamuju city on Sulawesi's western coast. Due to limitations of the navy's sonar equipment, what the metal was remained unclear, and Indonesia had no other equipment of its own. A United States Navy oceanographic survey ship, Mary Sears, arrived in the area on 9 January with better equipment to help identify the objects, and on the same date, a Canadian jet with five separate air crews, working in shifts, was sent to aid with aerial mapping of the suspected location. The Indonesian Marine and Fishery Department has since suggested that the metal objects instead could have been instruments deployed to study the underwater sea current. A total of 12 Indonesian Navy ships was deployed in the area, including the KRI Ajak, KRI Leuser, and KRI Nala. Extra underwater equipment, including a metal detector and an undersea camera, was sent from the United States, and arrived aboard the USNS Mary Sears on 17 January. The flight recorders were subsequently located elsewhere, in the waters in an area known as Majene, and a wide, sweeping search of the area revealed high amounts of scattered debris there, too. This debris was analysed to confirm it belonged to the 737.
Floating debris
The aircraft's right horizontal stabiliser was found by a fisherman, south of Pare Pare, about 300 m (980 ft) off the beach on 11 January, although it was not originally handed in, as its discoverer thought it to be a piece of plywood, only later realising it was a piece of the tail. This was confirmed by the part number on the stabiliser, 65C25746-76, which matched that of components on the missing 737. The fisherman received a reward of 50 million rupiah (equivalent to about $5,500) for his discovery. Later, other parts of the aircraft, including passenger seats, life jackets, a food tray, part of an aircraft tire, eight pieces of aluminium and fibre, an ID card, a flare, and a headrest were also recovered from the area. By 13 January, a piece of a wing was also recovered. Whether the 1.5-metre-long (4 ft 11 in) section was a section of the right wing or the left wing was unclear, although it was examined in an attempt to discover this. The total count of recovered objects associated with aircraft, as of 29 January, was 206, of which 194 were definitely from the 737. Pieces of clothing thought to belong to passengers were also recovered, and on 15 January, pieces of human hair and what is thought to be human scalp were recovered from a headrest that had been pulled from the sea. They were DNA tested to attempt to identify them, but the results of this testing are unknown.