Indonesia’s Lion Air jet that crashed last month should have been grounded over a recurrent technical problem and never permitted to make the fatal flight.
This was the interim verdict of the Indonesian Transport Safety agency in a report released today that took aim at the carrier’s poor safety culture.
The Boeing 737 MAX vanished from radar about 13 minutes after taking off from Jakarta on October 29, slamming into the Java Sea moments after it had asked to return to the capital.
The preliminary crash report from the agency did not pinpoint a definitive cause of the accident, which killed all 189 people on board, with a final report not likely to be filed until next year.
But investigators said 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 to the fatal flight.
Its second last flight was from Denpasar in Bali to Jakarta.
“During (that) flight, the plane was experiencing a technical problem but the pilot decided to continue,” Nurcahyo Utomo, aviation head at the National Transport Safety Committee, told reporters.
“The plane was no longer airworthy and it should not have kept” flying, he added.
The findings will heighten concerns there were problems with key systems in one of the world’s newest and most advanced commercial passenger planes.
Investigators have previously said the doomed aircraft had problems with its airspeed indicator and angle of attack (AOA) sensors, prompting Boeing to issue a special bulletin telling operators what to do when they face the same situation.
The report confirmed that initial finding, saying the plane’s data recorder detected an issue with the AoA.
It also said the plane’s “stick shaker” — the steering-wheel like handles in front of the pilots that vibrates to warn of a system malfunction — was “activated and continued for most of the fight.”
An AOA sensor provides data about the angle at which air is passing over the wings and tells pilots how much lift a plane is getting. The information can be critical in preventing an aircraft from stalling.
The Indonesian National Transportation Safety Committee has retrieved one of the plane’s black boxes — the flight data recorder — but is yet to locate the cockpit voice recorder.
Black box data showed the plane also had an airspeed indicator issue on multiple earlier flights, investigators said.
Lion must take steps “to improve the safety culture” and ensure “all the operation documents are properly filled and documented”, the transport agency said.
Despite a dubious safety record and an avalanche of complaints over shoddy service, the budget carrier’s parent Lion Air Group, which also operates Batik Air and Wings Air, has captured half the domestic market in less than 20 years of operation to become Southeast Asia’s biggest airline.