Indonesian investigators found the blame for going around with a Boeing 737 Max incident that killed 189 people a year ago.
After releasing their final report on Friday, air accident investigators concluded that it was partly the fault of Boeing, Lion Air and the pilots themselves.
They criticized Boeing's design decisions that made the aircraft vulnerable to the failure of a single sensor.
They criticized the US security regulators who certified the aircraft.
And they pointed the finger at one of their airlines, Lion Air, for inadequate training and maintenance of pilots.
Investigators claimed that a combination of nine major factors condemned the brand new Boeing jet which crashed in the Java Sea shortly after take-off on 29 October 2018.
"If one of the nine had not occurred, perhaps the accident would not have happened," chief investigator Nurcahyo Utomo told a news conference.
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Many of the problems had previously been disclosed in a preliminary report that the Indonesian authorities had published last year.
However, the release of the final report will probably put more pressure on Boeing, which is being investigated by the US Department of Justice and the US Congress.
On October 29 a Lion Air flight made its final take-off from Jakarta.
Hours later, the Boeing 737 MAX plane plunged into the Java Sea, killing all 189 people on board.
Although the aircraft was declared airborne before expelling Jakarta, several relatives of the victims of the crash went ahead and filed a lawsuit against Boeing.
Boeing is still working to repair its best-selling aircraft seven months after all the Max jets were grounded following a second accident on March 10 in Ethiopia, which killed 157 people.
The final report on that incident is in a few months, but preliminary results have revealed significant similarities to the disaster in Indonesia.
MAIN BUTTONS FROM THE REPORT:
• Boeing's design of a critical flight control system was a key factor in the accident, repeatedly pushing the nose of the aircraft down.
The system, called MCAS, was based on a single sensor to measure the direction of air flow, making it vulnerable in the event of failure of the sensor to switch on, which it did.
Boeing also formulated incorrect assumptions about the speed with which pilots could respond to a malfunction and did not inform pilots of the existence of MCAS until after the Lion Air accident, making it more difficult for Lion pilots Air save the plane and its passengers.
• Lion Air pilots who had problems on a previous flight were unable to write it down properly in the aircraft's logbook, so maintenance crews could not make the necessary repairs.
Pilots on the fatal flight failed to perform the correct emergency procedure for an upside-down pitching of the plane.
The copilot failed to understand the situation and was worried about running the wrong emergency checklist.
• The supervision of the safety regulators that certified the aircraft could have been much better.
A malfunction of MCAS was considered a "serious" but not "dangerous" or "catastrophic" safety problem – classifications that would have required a more thorough revision.
Boeing's assumptions about how quickly pilots would respond to a problem turned out to be too optimistic, but they met the Federal Aviation Administration's leadership.
Flight 610 of the air carrier Lion Air disappeared from the radar after air traffic control was told that the aircraft had air altitude and speed problems.
He plunged into the sea just 13 minutes after take-off.
The plane had been flying for two months, but started having problems a few days before the accident.
A new "angle of attack" sensor, which measures the direction of the aircraft relative to the incoming air, was installed while the plane was on the Indonesian island of Bali the day before dell & # 39; accident. The sensor was not properly calibrated during a previous repair, leaving it out of alignment and may not have been properly tested.
On a flight the day before the accident, the pilots were bombarded with warnings about speed, altitude and an imminent stop.
The captain and the copilot regained control of the aircraft by manually overwriting the automated system with the help of a third Lion Air pilot who was hitchhiking in the cockpit jump seat. The plane arrived in Jakarta safely, but the pilots did not fully report the problems they had encountered, which prevented maintenance crews from investigating, according to the report.
"Let's just say that that flight from Bali to Jakarta was very lucky," said the Indonesian aviation expert Gerry Soejatman, who blamed most of the accident the day after Boeing.
With the report, the relatives of those on flight 610 were again in mourning.
Muhammad Asdori, whose brother and nephew were killed, accused Boeing of negligence by failing to predict how the pilots would react in an emergency. "We are very angry," he said. "We were even more angry when we learned that they had admitted their mistake only when the second Max 8 plane crashed in Ethiopia."
Boeing said it was considering the discoveries of Indonesia while making maximum changes.
It is redesigning the MCAS to get readings from both sensors of the angle of attack on the plane, not just one.
MCAS will push the nose of the plane down only once on the basis of an incorrect sensor reading and will push down with less force.
The company is also updating the crew's manuals and pilots' training. Boeing aims to put Max back in service by the end of the year.
The company has again published advertisements in major US newspapers on Friday, offering again its apology and describing in detail the steps it is taking to compensate the families of the victims, update Max and improve its safety culture.
"As we continue to make steady progress in securing the 737 MAX in service, we will never forget these losses and our commitment to safety, quality and integrity is unshakable," said Boeing in the announcement. .
The FAA has stated that it will take the investigators' recommendations into consideration while reviewing Boeing's proposed changes to the maximum.
The FAA has promised that it will leave the plane flying again only when it is certain that it is safe.
Air travel in Indonesia, the fourth most populous country in the world with almost 270 million people, has increased and air carriers like Lion Air have sprung up to meet demand.
But the industry has struggled to keep up and faces a shortage of pilots, outdated infrastructure and poor regulatory supervision.
The country has been plagued by a series of fatal accidents in recent years.