Jet crash causes: pilots, Boeing, maintenance

JAKARTA, Indonesia — An Indonesian investigation found that a combination of design flaws by Boeing and inadequate pilot training and maintenance lapses by Lion Air doomed a Boeing 737 Max jet that plunged into the Java Sea a year ago, killing 189 people.

The final accident report released Friday said Lion Air flight 610, from Indonesia’s capital Jakarta to the nearby town of Pangkal Pinang off Sumatra island, crashed partly because the pilots were never told how to quickly respond to malfunctions of the Boeing jet’s automated flightcontrol system.

Investigators, however, indicated there was plenty of blame to go around. They said that nine critical problems were responsible for the tragedy.

“If one of the nine hadn’t occurred, maybe the accident wouldn’t have happened,” chief investigator Nurcahyo Utomo said at a news conference.

Budget carrier Lion Air’s jet vanished from radar after air traffic control was told the plane had altitude and air speed troubles. It plunged into the sea just 13 minutes after takeoff on Oct. 29, 2018.

Five months later, a similar malfunction caused a Max jet to crash in Ethiopia, killing all 157 people on board.

That led to the grounding of all 737 Max jets and put Boeing under intense pressure to explain problems associated with the flightcontrol system, known as MCAS. The aircraft still has not resumed flying. Boeing officials say the company is nearly finished with changes to flight software and computers.

The report released Friday outlined various missteps. The aircraft, only in use for two months, began having problems a few days before it crashed. A new angle of attack sensor was installed while the aircraft was on the Indonesian island of Bali a day before the crash, but it had been miscalibrated during an earlier repair, leaving it 21 degrees out of alignment. The problem was missed when it was installed, and the investigators said they were unable to find out if the new sensor was properly tested.

Investigators said the Indian captain and the Indonesian copilot were unaware of the entire situation because a warning function that should have told the pilots the two angle of attack sensors were out of sync was not installed on the aircraft.

Utomo, the Indonesian investigator, said coordination inside the cockpit was a problem during what was only meant to be an hourlong flight.

“We found that during the accident flight both pilots were busy and preoccupied by their own tasks,” he said. “One pilot was doing the job of flying while the other pilot was completing procedures, so the communication between them did not run well.”