Lion Air Flight 610 crashed off the coast of Indonesia last October, killing 189 people. Indonesian officials believe the failure of a sensor may have triggered an automated software system designed to prevent the plane from stalling. However, the system may have brought the plane down as pilots struggled to override it.
During the recent tests, the simulator pilots found they had mere seconds to shut down the system and prevent the plane going into a nosedive, the Times said, citing two unnamed people involved in the tests.
The system, known as MCAS, “as originally designed and explained, left little room for error,” according to the report. “Those involved in the testing hadn’t fully understood just how powerful the system was until they flew the plane on a 737 Max simulator,” the Times reported.
At least some of the tests described by the Times took place over the weekend, the paper reported.
On Saturday, pilots and training officials from Southwest Airlines, American Airlines and United Airlines met with Boeing officials to review updated software for 737 Max planes in the Seattle area, where the model is assembled, multiple airline sources told CNN on Monday. The software updates are intended to decrease the chances of triggering the MCAS system.
The pilots ran simulated flights using the current and updated software, one of the sources told CNN, adding that each flight landed safely.
MCAS is a key focus of the investigations into the Lion Air disaster and the crash of an Ethiopian Airlines Boeing 737 Max 8 flight on March 10 that killed all 157 people on board. Both jets crashed minutes after takeoff, and in both cases the pilots reported problems minutes into the flights.
During the Lion Air flight’s last minutes, pilots searched in a handbook for a way to stop the plane from nosediving, according to a Reuters report.
The Trump administration grounded all Boeing 737 Max planes indefinitely three days after the Ethiopia crash, and after the rest of the world had already done the same.
In a statement Sunday, Boeing called the weekend meeting a “productive session” and said that it had invited more than 200 pilots and technicians, as well as regulators, to an informational session at the company’s production facility in Renton, Washington, on Wednesday.
“This is part of our ongoing effort to share more details about our plan for supporting the safe return of the 737 MAX to commercial service,” Boeing said.
Updated software required less intervention from pilots
In the simulations run over the weekend with the current MCAS software, the test pilots used existing procedures to disable the system, while test flights using the new software required less intervention from the pilots, a source told CNN.
The updated software designed by Boeing uses input from two sensors on the nose of the plane, instead of one, and is designed to not trigger the MCAS system repeatedly, which is believed to have pitched the Lion Air plane’s nose down so sharply that the pilots’ attempts to regain control were futile.
The Federal Aviation Administration (FAA), which is part of efforts to test the new software, declined to comment. One source familiar with the tests said the FAA is expected to receive the software early this week.
The FAA is not expected to allow dozens of 737 MAX planes it grounded to fly again until it learns more about the causes of the Ethiopian Air crash, the source said.
Flight data and cockpit voice recordings are being analyzed in Ethiopia, where authorities have handed over segments of flight voice and data recordings from the aircraft’s black boxes to US embassy officials in Addis Ababa, a source with knowledge of the investigation told CNN on Monday.
CNN’s David Shortell, Evan Perez, Gregory Wallace and Samira Jafari contributed to this report.