Lion Air crash: Investigators say the plane was not "able to fly"

Indonesian researchers said the Lion Air plane that crashed last month, killing 189 people, was

A preliminary report revealed that technical problems had been reported in previous flights.

The 737 Max is a new version of the original Boeing 737 and has become the best-selling aircraft.

The preliminary report details what the authorities know about the short time the plane was in the air, but the investigators said it did not give a definitive cause to the accident.

What does the report contain?

The findings of the National Transportation Safety Committee (KNKT) suggest that Lion Air put the aircraft back into service when it had had problems with previous flights.

The pilots appeared to have problems with an automated system designed to prevent the aircraft from being stuck, a new feature of the 737 Max family.

Anti-lock systems prevent an aircraft from heading too far, where it could lose lift.

However, during the October 29th flight, the aircraft's automatic antilock system had forced the aircraft to sting, even when the aircraft was not stopping, likely due to a defective sensor, according to the report.

The pilots tried to correct this by pointing the nose up, until the system repelled it again. It happened more than 20 times.

The fiancée of the victim takes only pictures of the wedding.

Accident of Lion Air: images of the tragedy unfolding.

Social networks identify the shock couple

The reason why pilots did not use procedures to disable the automated system is unclear.

Nurcahyo Utomo, head of the National Transportation Safety Committee, said it was "too early to conclude" whether the disaster recovery system contributed to the accident.

He added that the plane had encountered similar problems during his previous flight between Denpasar in Bali and Jakarta.

"In our opinion, the aircraft was no longer airworthy and should not have continued," he said. However, the report of the committee itself does not explain this conclusion.

The report states that Lion Air's safety culture should be improved and that the airline should ensure that the operations manual is followed "to improve the safety culture".

It also states that the carrier must ensure that "all transaction documents are duly completed and documented".

What does Boeing say?

In a statement, aircraft manufacturer Boeing said he was "deeply saddened" by the loss of the Lion Air flight.

"As our customers and their passengers continue to transport the 737 Max to hundreds of destinations around the world every day, they believe the 737 Max is as safe as any plane flying through the air."

Boeing stated that "the appropriate procedure for dealing with the movement of the unintentional horizontal stabilizer" was included in the corresponding flight manuals.

He added that the preliminary report showed that the correct procedures for neutralizing the nose of the aircraft that had been pushed to the ground had been carried out during the Denpasar flight, the day before the accident.

However, it was unclear whether the procedures had been followed during the flight that crashed on October 29, Boeing added.

In an interview with the BBC, Nurcahyo Utomo, KNKT's chief of aviation, appeared to challenge Boeing's story about flight manuals.

"We did not find any information in the manual corresponding to the new function of the 737-MAX, related to the function of the blocking prevention system," he said.

Some pilots also complained that they did not receive all the relevant information about the differences between the latest anti-lock system and older models, according to US media.

How did the accident of October 29th develop?

The aircraft was on a one-hour trip to the western city of Pangkal Pinang when it fell.

The plane crashed after a request from the pilot for permission to return to the airport a few minutes after taking off from Jakarta.

Researchers had previously revealed that the aircraft, during previous flights, had encountered technical problems related to speed and altitude readings.

Therefore, the "angle of attack" sensor, which contributes to these readings, had been modified the day before the shock.

The aircraft's flight data recorder has been found, but the authorities have still not located the flight recorder.