Image copyrightReutersImage caption The families of the victims visited the site of the crash to pay tribute Indonesian authorities have recommended that budget airline Lion Air improve its safety culture, in a preliminary report into last month's deadly crash.On 29 October flight JT 610 crashed into the Java Sea shortly after departing Jakarta, killing all 189 people on board.The report details what is known by authorities about the short time the plane was in the air.However, it does not give a definitive cause for the accident.What's in the reportThe preliminary report by the Indonesian Transport Safety Committee (KNKT) suggests that Lion Air kept putting the plane back into service despite repeatedly failing to fix a problem with the airspeed indicator in the days leading up the flight.It also indicated that pilots struggled with the aircraft's anti-stall automated system, which was a new feature in the 737 Max family of aircraft by Boeing.In its report the Indonesian Transport Safety Committee said the airline should ensure the operations manual is followed "in order to improve the safety culture and to enable the pilot to make proper decision to continue the flight".It also said the carrier must ensure "all operations documents are properly filled and documented".Image copyrightReutersImage caption Investigators examine one of the engines from the doomed Lion Air flight JT 610 Aviation head at the committee Nurcahyo Utomo, told reporters that because of the technical issues on a previous flight, "in our opinion, the plane was no longer airworthy and it should not have continued," news agency AFP says.
The committee report itself though does not spell out that conclusion.
How did the crash unfoldThe plane was making a one-hour journey to the western city of Pangkal Pinang when it went down.The jet crashed into the Java Sea following a request from the pilot for permission to turn back to the airport minutes after taking off from Jakarta.Investigators had previously revealed that the plane had on multiple previous flights experienced technical problems related to airspeed and altitude readings.Therefore the "angle-of-attack" sensor, which contributes to those readings, had been changed the day before the crash.
However, media reports have suggested the sensor malfunctioned on the ill-fated flight as well, causing the anti-stall system to pitch the nose of the aircraft downwards.It is unclear why the pilots did not employ procedures to disable the automated system.One of the black box recorders from the flight - the flight data recorder- has been retrieved but authorities are yet to locate the cockpit voice recorder which could provide more information about how the pilots reacted.Victims' families are suing aircraft maker Boeing over alleged faults with the jet's design, focussing on the automated safety feature.Indonesia's air safety recordBudget airline Lion Air has over the past years risen to become a major player in South East Asia's low cost aviation sector.
The airline which also operates Batik Air and Wings Air has a dubious safety record though and has had more accidents than other airlines in the country.
Overall, Indonesia's aviation safety record has improved a lot since the days when even its national carrier Garuda was blacklisted from European and US airports over safety concerns.