Since a Lion Air flight crashed into Indonesia’s Java Sea on October 29, killing all 189 passengers and crew members on board, information has emerged indicating that mechanical faults may have contributed to the aviation disaster, the country’s worst in over two decades.
The plane reportedly fell out of radio contact some 13 minutes after taking off from Jakarta on a routine flight to Pangkal Pinang, the capital of the Bangka Belitung Islands province. Witnesses reported seeing it nosedive as it plunged into the sea.
Over the past week, rescuers have combed the area near the crash site, searching for the remains of those who perished. Tragically, on November 2, Syachrul Anto, a 48-year-old member of the rescue team, died while recovering material from the plane.
The plane’s black box, containing flight information, was recovered on November 1. A second black box, with audio from the cockpit, has yet to be discovered. Indonesian aviation authorities are expected to release a preliminary report at the end of November, while the findings of a full investigation will not likely be made public for several months.
Already, however, major questions have emerged about whether the plane should have been in use at the time of the accident. The crash has again drawn attention to issues of maintenance and safety in the Indonesian and global airline industry. There is continuous cost-cutting and a relentless drive by every carrier to win market share amid a rapid growth in the number of low-cost carriers.
On Thursday, the plane’s manufacturer, Boeing, issued a bulletin instructing crews to review an existing safety procedure in the event that Angle of Attack (AOA) sensors failed to provide accurate information. It stated that Indonesia’s “National Transportation Safety Committee (NTSC) has indicated that Lion Air flight 610 experienced erroneous input from one of its AOA sensors.”
The news has sparked fears of other potential dangers around the world. The Lion plane was a Boeing 737-Max 8, one of the company’s newest models, which has been rolled out internationally. According to the company, the United States Federal Aviation Administration ordered domestic US carriers to follow its bulletin on AOA failures, and would “take further appropriate actions depending on the results of the investigation.”
AOA sensors feed information about the angle of wind passing over the wings of a plane, and how much lift it is getting. Such data can be decisive in stopping a plane from stalling—an outcome that would be consistent with reports that the Lion Air flight nose-dived.
On Monday, NTSC head Soerjanto Tjahjono and Nurcahyo Utomo, who is investigating the crash, confirmed that black box data revealed issues with the plane’s airspeed indicator on the four flights prior to the crash. On the last flight before the disaster, the right and left AOA sensors had given indications that diverged by about 20 degrees from one another.
The discrepancy reportedly resulted in a sudden dive, but the pilots were able to recover altitude. They completed the flight, from Bali to Jakarta, at a lower than usual height in a bid to avoid more powerful wind gusts associated with high altitudes. An anonymous pilot told Reuters that the captain had requested to return to Bali, a claim later denied by airport authorities.
Gerry Soejatman, an aviation analyst, told the Guardian that the problems encountered by the plane in the days before the disaster “may be wider than initially believed.” He said the combined issues with airspeed indications and the AOA sensors could indicate flaws in the air data reference unit.
That key unit provides data from indicators for temperature, AOA, airspeed and altitude to the pilots’ electronic flight instrument system. If it is malfunctioning, pilots may be fed incorrect information.
Boeing is one of the largest aircraft manufacturers in the world and the biggest US exporter by dollar value. Last year, it had a net income of over $8 billion. The company, along with aviation authorities, will inevitably seek to ensure that any safety concerns do not affect its profitability.
The revelations sparked an angry response from relatives of those who died. Bambang Sukandar, whose son was killed, told Reuters: “Lion Air said the problem was fixed. Is it true the problem was cleared? If not, technicians in charge must be responsible.”
The father of Shandy Johan Ramadhan, another passenger, said Lion Air had “failed” the victims’ families. “Since the time of the crisis, I was never contacted by Lion Air,” he said. “We lost our child, but there was no empathy that Lion Air showed to us.”
Indonesia has a long history of airplane disasters. Lion Air, a cut-price carrier, has had 12 recorded accidents since it began operations in 2000. Some of the incidents pointed to lax safety and maintenance procedures.
In February 2016, a Lion Air flight overshot the runway at Surabaya’s Juanda International Airport. The NTSC found that the incident, which did not lead to any fatalities, was a product of poor crew resource management, resulting in incorrect landing procedures.
In April 2017, one of the company’s planes spilt 300 litres of fuel on the tarmac of Juanda International Airport, forcing the plane’s emergency evacuation. An initial statement by a Lion Air official indicated that the accident resulted from a non-functioning safety valve and overflow detector.
A host of accidents, including serious incidents involving the national carrier, Garuda Indonesia, have left Indonesia with a poor aviation reputation. In 2007, the European Union banned all Indonesian airlines from flying into the continent. The ban was subsequently lifted, but the latest disaster has led to speculation of possible similar restrictions.
The aviation issues are part of a broader crisis of public transportation. Ferries, carrying hundreds of people across the archipelago, are frequently unseaworthy. In one of the latest incidents, more than 193 people were killed in June after a wooden vessel capsized on Lake Tabo, in northern Sumatra. Despite its legal capacity of 43 people, it had almost 200 passengers on board.