Mandala Airlines Flight 091 (RI091/MDL091) was a scheduled domestic passenger flight from Medan to Jakarta, operated by Mandala Airlines with a Boeing 737-200. On 5 September 2005 at 10:15 a.m. WIB (UTC+7), the aircraft stalled and crashed into a heavily populated residential area seconds after taking off from Polonia International Airport. Of the 117 passengers and crew on board, only 17 survived. An additional 49 civilians on the ground were killed, making a total of 149 fatalities.
The crash of Flight 091 was a shock to North Sumatrans as the leader of North Sumatra province, Governor Rizal Nurdin, and his predecessor, Raja Inal Siregar, were among the passengers and both were killed in the crash.
The Indonesian National Transportation Safety Committee (NTSC) concluded that the crash was caused by the actions of the flight crew, in that they did not configure the aircraft properly for take-off. The retracted flaps and slats resulted in the aircraft being unable to fly due to insufficient lift. The aircraft take-off warning was not heard and investigators stated that it was possible the pilots did not receive a warning about the improper configuration, and were therefore unaware of their erroneous actions.
Aircraft
The aircraft was a Boeing 737-230 Adv with registration PK-RIM. Built in 1981, it was acquired by Mandala Airlines in October 1994. The aircraft was 24 years old at the time of the accident and had a Certificate of Airworthiness valid until November 2005.
Passengers and crews
The aircraft was carrying 112 passengers and five crew members, consisting of two flight crew and three cabin crew. In total there were 114 adults and three children on board. The majority of those on board were Indonesians; however, there were also foreigners on the aircraft. The Chinese embassy in Jakarta confirmed that there were two Chinese citizens from Fujian on board Flight 091. Officials also confirmed the presence of a 3-year-old Japanese child on board Flight 091, who was killed in the crash. A 17-month-old girl and her mother were among the survivors.
Among the passengers were the incumbent governor of North Sumatra, Rizal Nurdin, and his immediate predecessor, Raja Inal Siregar. Nurdin was flying with his daughter to attend a national Indonesian governors meeting with then-President of Indonesia Susilo Bambang Yudhoyono. A member of the Indonesia Regional Representative Council (DPD), Abdul Halim, was also on board the flight.
The captain, 34-year-old Askar Timur, had 7,552 flight hours, including 7,302 hours on the Boeing 737. The first officer, 31-year-old Daufir Efendi, had 2,353 total flight hours, with 685 of them on the Boeing 737. The cabin crewmembers were Dewi Setiasih (24), Novi Maulana Sofa (22) and Agnes Retnaning Lestari (31).
Flight
Flight 091 was a scheduled domestic passenger flight from Polonia International Airport (now Soewondo Air Force Base) in Medan, the largest city in Sumatra, to Soekarno-Hatta International Airport in the Indonesian capital Jakarta. Flight 091 was the second trip of the day for the aircraft, which had earlier flown from Jakarta to Medan with the same flight crew. The aircraft was pushed back at 09:52 a.m. and start-up clearance was given immediately after. It then taxied out onto Runway 23 and was cleared to take off at 10:03 a.m. with an altitude of 1,500 ft (460 m).
Accident
Flight crews then added thrust and the aircraft began rolling on the runway. As it was rolling, some passengers noted that the aircraft took longer than usual to take off from the airport, even though the aircraft was already in a nose up position. The aircraft briefly took off, then veered to the left and to the right, stalled and then the tail impacted the runway. As the tail struck the runway, it left marks on Runway 23.
The aircraft then struck several approach lights located at the end of the runway before traveling across grass, crossing a small river and finally crashing onto the crowded Djamin Ginting road. Onlookers and motorists on the road panicked as the aircraft came towards them. The left wing struck a building and the aircraft exploded into flames. It broke into three parts. Passengers on the aft fuselage stated that the front part of the aircraft was obliterated as the aircraft exploded. It continued to slide onto the road, hitting multiple cars, bikes, powerlines and streetlamps and destroying several shops and houses. Several unaware drivers got their vehicles flipped by the sliding aircraft and subsequently burst into flames. The aft fuselage then came to rest in the middle of the road.
As the aircraft's 41,000 kg (90,000 lb) of fuel ignited, it caused a massive fire in the area. Multiple houses and shops nearby caught fire, trapping residents and shoppers. The situation was chaotic and was filled with screams of residents who were searching for their relatives and families in the neighborhood, while dozens of people were seen running with their clothes alight. In the Polonia airport control tower, air traffic controllers immediately closed the airport and notified the airport's fire brigade about the crash. However, when fire crews arrived at the end of Runway 23, they realized that the crash site was outside the airport perimeter and that there was no access to the accident site.
Locals immediately assisted the search and rescue operation. Medan's firefighting units and ambulances were immediately dispatched onto the scene. As rescuers had not arrived at the crash site, multiple victims had already been transported with private cars and public minibuses. Rescuers were quickly overwhelmed by the number of victims and the number of onlookers at the crash site. As there was no coordination among the rescue team, the evacuation was severely hampered. The chaotic situation and crowded condition of the crash site rendered the evacuation process to be difficult.
Survivors escaped from the burning aircraft through a gaping hole at the front part of the remaining aft fuselage. As the fire on the aircraft intensified, residents noticed that one of the pilots was still alive. They then tried to extricate him from his seat. However, as they were unfamiliar with the seat's harness, they were unable to get him out. An explosion suddenly struck the cockpit, causing the rescuers to run away.
To ease the evacuation process, residents had to line up the bodies that they had found earlier. Indonesian Army personnel were deployed to assist the search and rescue operation. Rain then started to fall around noon, effectively dousing the flames in the area. According to residents who had tried to save the pilot, the pilot’s seat was completely burnt and his body was nowhere to be found. By this time, more than 50 bodies had been recovered. They were taken to various hospitals across Medan, mainly Adam Malik Hospital. Officials also used the hall of Polonia International Airport to store victims pending identification.
On the night of 5 September, the Indonesian Minister of Transportation Hatta Rajasa announced the death toll from the crash. A total of 149 people had been killed, of whom 49 were civilians on the ground. 17 passengers survived the accident, with 100 of those on board (including all five crew members) known to have died. Two of the survivors, a mother and her 17-month-old child, were unharmed in the crash. Most of the survivors were seated at the aft fuselage. A passenger told Indonesian news channel MetroTV from hospital that he and five other people seated in the back of the plane in Row 20 had all survived. "There was the sound of an explosion in the front and there was fire and then the aircraft fell," he said. The survivor said he escaped the blazing wreck by jumping through the torn fuselage and fleeing on foot as four large explosions erupted behind him. Officials reported that at least 16 houses and 32 vehicles had been destroyed by the crash of Flight 091.
Rizal Nurdin, the Governor of North Sumatra, former governor Raja Inal Siregar, his immediate predecessor, and Senator Abdul Halim Harahap, a member of the Regional Representative Council, were among the dead.
Response
In response to the death of Senator Abdul Halim, the Indonesian Regional Representative Council declared 3 days of mourning. The Indonesian flag in the building of the People's Consultative Assembly was flown at half-mast. To honor the victims of the crash, a minute's silence was observed by the Indonesian House of Representatives. The North Sumatra provincial government also declared 3 days of mourning and ordered flags to be flown at half-mast throughout the province. Meanwhile, President Yudhoyono immediately asked the Indonesian Ministry of Transportation to investigate the crash. He postponed the national Indonesian governors meeting in Jakarta and decided to visit the crash site. He later attended the funeral of North Sumatran Governor Rizal Nurdin.
Members of the 5th Commission of the Indonesian People's Representative Council, responsible for transportation in Indonesia, announced it would summon the then-Indonesian Minister of Transportation Hatta Rajasa and representatives from Mandala Airlines in response to the crash. Speaker of the 5th Commission, Sofyan Mille, also asked the Indonesian government to regulate low-cost carriers in Indonesia in order to prevent "cost-cutting".
In the following days, the Indonesian Ministry of Transportation conducted a "special check" on multiple Boeing 737-200s from various domestic airliners at Soekarno-Hatta International Airport. The check resulted in the grounding of four Boeing 737-200s as officials reported several maintenance issues with the aircraft. The aircraft were grounded indefinitely until the operators resolved the issues.
The Indonesian Ministry of Home Affairs appointed then-deputy governor of North Sumatra Rudolf Pardede as the acting governor of North Sumatra. This decision, however, was met with opposition from members of several parties due to an alleged falsified academic certificate. Party members even threatened to walk out from every meeting attended by Pardede in the future. North Sumatran students also held a demonstration to protest the decision. This sparked a political crisis in North Sumatra which lasted until the next year. Pardede was subsequently inaugurated as the governor of North Sumatra in March 2006.
Mandala Airlines stated that they would fly relatives of the victims to Medan using two aircraft from their fleet. They later stated that a 7-day tahlil would be held at the airline's main headquarters in Jakarta. Indonesian state-owned insurance company, Jasa Raharja, announced that relatives of each person killed in the accident would receive 50 million rupiah compensation and those who were injured would receive 25 million rupiah. Vice President Jusuf Kalla reassured families that each victim would be compensated by the state.
One day after the crash, officials stated that they had been unable to identify 60 dead bodies and that a mass grave would be dug. The mass grave was dug at the same location where victims of Garuda Indonesia Flight 152 and 1979 Garuda Fokker F28 crash were buried. A mass funeral was held on 7 September and the procession was led by Abdillah, the mayor of Medan.
Investigation
The investigation was carried out by the Indonesian National Transportation Safety Committee (NTSC), with assistance from the United States National Transportation Safety Board (NTSB) and representatives from Boeing as the manufacturer of the aircraft. The NTSC had also requested the Australian and Thai authorities for a readout on the black boxes. According to Rita Wijaya, a member of the NTSC, the investigation could take up to one year. She promised that the final report on the crash would be made public.
Both flight recorders were recovered immediately after the crash and were sent to the United States for a readout by the NTSB. Even though both recorders were found in good condition, the NTSC noted that there was a malfunction on the cockpit area microphone (CAM). As such, investigators could not determine the actual situation inside the cockpit due to the poor quality of the cockpit voice recorder (CVR) data.
According to investigators, since Flight 091 had difficulties in take-off, investigators decided to investigate three main possible causes; the weight and balance of the aircraft, the condition of the engines, and the configuration of the flaps and slats.