Citing "safety experts involved in the investigation, as well as mid-level FAA officials and airline pilots", the Journal reported Monday that the automated stall-prevention system on Boeing 737 MAX 8 and MAX 9 models - meant to help cockpit crews avoid mistakenly raising a plane's nose dangerously high - "under unusual conditions can push it down unexpectedly and so strongly that flight crews can't pull it back up".
Even though this problem was - according to investigators - not covered in the operating manual, pilots did have access to a checklist created to turn off errant systems when the plane started nosing downwards at the wrong time, said Soejono, a Lion Air instructor who like many Indonesians goes by one name.
Few details have been released about the underlying causes of the Lion Air crash October 29 in the sea near Jakarta, but Indonesian investigators say that an erroneous sensor prompted the plane's computers to push the aircraft into a steep dive.
But if that nose-down command is triggered by faulty sensor readings - as suspected in the Lion Air crash - pilots can struggle to control the plane and it can go into a dive and perhaps crash.
An Air New Zealand flight from Los Angeles had been stood down after the plane was clipped by another aircraft while on the tarmac. "It is information that we were not privy to in training or in any other manuals or materials", Tajer told Reuters. It wasn't in our books.More news: Cleveland Browns: Revisiting moves that have worked at the bye
"We've just been informed that there's an entire new system on the Max called the MCAS", said Captain Dennis Tajer, spokesman for the Allied Pilots Association, the union for pilots at American Airlines, and a 737 pilot.
"I was not pleased".
"We are taking every measure to fully understand all aspects of this incident, working closely with the investigating team and all regulatory authorities involved", the company said in a statement by email.
The Oct 29 crash was the first accident involving the 737 MAX, an updated version of Boeing's workhorse narrowbody jet that entered service a year ago.
Southwest spokeswoman Brandy King said the new automated maneuvering system was not included in the operating manual for MAX models. Boeing hasn't yet officially commented on the reports.More news: Colts win 3rd straight game, beating the Jaguars 29-26
Boeing has delivered versions of the new plane to numerous largest airlines, including American and Southwest, according to the company's website.
The pilot of Flight 610 had more than 6,000 flying hours while the co-pilot had more than 5,000 hours, according to the airline.
Boeing said it is confident in the safety of the 737 Max family of jets.
Boeing and the FAA said in the directives that an existing procedure could have halted the dive.
The first Boeing 737 MAX was delivered only in May 2017, and so not much was known about this aircraft, except what was published by Boeing for the pilots and airlines in its Flight Crew Operations Manual (FCOM) and Quick Reference Handbook (QRH). The FAA's emergency directive required that USA carriers revise flight manuals and said the agency "will take further action if findings from the accident investigation warrant". All 189 people on board were killed.More news: The FA’s post-Brexit plan that could drastically alter the Liverpool squad
The airline said the Boeing 777-300 was at the gate and ready for boarding when the horizontal stabiliser on its tail was clipped by another aircraft being towed causing significant damage.