FAULTY equipment and Indonesian carrier Lion Air’s own safety failures had pilots fighting for control of their Boeing 737 MAX 8 as it plunged into the Java Sea on October 28, killing all 189 people on board.

Investigators said they were still struggling to understand why the plane crashed, but they cited factors centred on faulty sensors and an automatic safety system that repeatedly forced the plane’s nose down despite the pilots’ efforts to correct the problem.

Based on the number of problems with the aircraft beforehand, they suggested the jet should not have been in service.

The National Transportation Safety Commission’s Nurcahyo Utomo said investigators were trying to work out from interviews with engineers why they deemed the Boeing 737 airworthy.

“We need to compare the statements of the engineers with the required procedures,” Utomo said.

Once the jet was airborne, the pilots appeared to have been overwhelmed, said another of the crash investigators, Ony Suryo Wibowo.

“The problem is if multiple malfunctions occur all at once, which one should be prioritised?” Wibowo said.

The lack of the aircraft’s cockpit voice recorder, which is still missing, is a dire obstacle to resolving that mystery, the investigators said.