ABC News tells the story of Indonesia-based budget airline Lion Air, which had ordered over 200 Boeing 737 MAX 8s at a cost of $22 billion — and what happened on a flight the day
before a fatal crash on October 29th, 2018:
[A]fter its first flight in May 2017, the 737 MAX 8 went 17 months without incident. Then, on Oct. 28, 2018, Lion Air Flight 610 from Bali to Jakarta experienced an in-flight emergency as the plane suddenly began to nosedive after take-off. “All of us were screaming like we are in a roller coaster,” said Rakhmat Robbi, a passenger on the flight. “To be honest, I [was] think[ing] it’s almost like my last flight and this is my last day.” The aircraft nosedived four times as the pilots struggled to regain control, according to Indonesia’s National Transportation Safety Committee (NTSC). A third pilot who just happened to be in the cockpit was able to help the two pilots resolve the situation and the plane landed safely in Jakarta.
However, according to the NTSC, the crew left incomplete notes about the details of the emergency. “The pilot reported that he had a problem with the speed and altitude indicated on [the] captain’s side,” said Capt. Nurcahyo Utomo, senior safety investigator of the NTSC. Nurcahyo said the captain failed to mention the plane’s trim system had suddenly activated, causing it to repeatedly nose dive. “The pilots were able to control it,” said aviation attorney Steven Marks. “They knew they had a problem. But they didn’t understand exactly what the nature of the problem was.”
Early the next morning, on Oct. 29, 2018, the same plane departed from Jakarta to Pangkal Pinang, Indonesia. Just 13 minutes after takeoff, Lion Air Flight 610 plummeted into the Java Sea. Authorities launched a search and rescue mission immediately, but all 189 people on board died.
The flight data recorder from Lion Air 610 revealed that the plane had gone out of control — it had moved up and down over 24 times before it finally dove into the sea at full speed. “I never knew… any case of the [sic] aircraft that fly down and up and up and down like this,” Nurcahyo said. “I knew that the pilot was fighting with the plane.” Nurcahyo said the NTSC asked Boeing about the kind of system on the 737 MAX that could have caused it to behave in such a manner. He said investigators were surprised to learn that Boeing had installed a flight control software program that could force the plane into a dive without the pilots’ knowledge… MCAS was accidentally triggered on both Lion Air flights because a defective angle of attack (AOA) sensor had transmitted incorrect information about the position of the plane’s nose. Although there are two AOA sensors on the 737 MAX, MCAS was only connected to one of them.
“It’s a lack of redundancy that appears to me to be unacceptable in airplane design,” said aviation journalist Christine Negroni, author of the book “The Crash Detectives…”
Boeing later told the pilots union of American Airlines it hadn’t revealed the existence of MCAS in the 737 flight manual “on the grounds that it didn’t want to inundate pilots with unnecessary information,” according to the article.
ABC also points out that a later investigation by the U.S. Congress “uncovered internal Boeing emails that showed some employees had raised concerns about the 737 MAX while it was still in development, and that they had questioned the safety culture of the company as well.”
