New York (AFP)

Boeing was inflicted Thursday a yellow card by a US federal regulator, who blames him for not taking into account the realities in flight of the pilots during the development of the 737 MAX, including two near accidents have made 346 dead.

Calling for changes in the aircraft certification process in the United States, the US transport regulator, the NTSB, believes in a report that Boeing and the Federal Aviation Agency (FAA) misjudged the reaction of pilots flight alerts in the event of malfunction of the MCAS anti-stall system, involved in the 737 MAX accidents.

When it is activated, the MCAS abruptly puts the plane in "dive" (nose to the ground). This happened on flights 302 from Ethiopian on March 10th and 610 from Lion Air on October 29th, 2018.

"We observed in both accidents that the crews did not react the way Boeing and the FAA thought they would," said Robert Sumwalt, the boss of the NTSB. "These assumptions (from Boeing and the FAA) were used to design the aircraft and we found a gap between these assumptions that served to certify the MAX and the reality, where the pilots were faced with multiple alarms and warnings. same time, "he castigates.

The Ethiopian Airlines and Lion Air crashes have resulted in ground immobilization for more than six months of the entire 737 MAX fleet around the world.

Boeing is currently working on changes required by regulators, including pilot training, to return to service.

When Boeing developed the MAX, he made the following assumption: if the MCAS activated unexpectedly, the pilots could deactivate it immediately by disconnecting the electric compensators.

The only problem was that the aircraft manufacturer had tested the MCAS failure only as an isolated problem, and had not wondered if its activation could not cause other malfunctions in the cockpit at the same time.

- Cascade of alerts and alarms -

In the Ethiopian and Lion Air accidents, according to the preliminary findings of the investigators, an impact probe error (AOA) caused activation of the MCAS, which in turn resulted in a cascade of alerts that would have overwhelmed the pilots, according to the NTSB.

Boeing and the FAA "have not explored all the possible alerts that may occur in the pilot's environment or the signals the pilots would face," said Dana Schulze, an official at NTSB. "According to research conducted over several years, multiple alerts and signals (in the cockpit) have a potential impact on pilots, who may not react the way we thought they would."

"The pilots' responses to the MCAS unanticipated actions were not consistent with the assumptions made by Boeing during the flight control system assessments during the design of the 737 MAX in the event of a hazard," the NTSB continues.

The regulator recommends to the FAA, the Civil Aviation Authority, to ask Boeing and other manufacturers to take into account, when designing software, the effects of triggering multiple alerts and alarms at the same time. the cockpit when determining how pilots might react quickly to a malfunction.

The regulator also recommends that the FAA develop "robust methods and tools" to validate assumptions related to pilot responses to significant safety issues in the aircraft design certification process.

In summary, aircraft manufacturers should develop technologies that would identify a problem during the flight. These technologies would also tell pilots what the procedure is.

"We are committed to working with the FAA to review the NTSB's recommendations," said Boeing, who was advised by an internal committee on Wednesday to change its cockpit design and take action to improve safety efficiency.

The FAA "will carefully consider the recommendations and those of other (authorities) at the time we evaluate the modifications proposed by Boeing 737 MAX," said a spokesman for the air regulator.

On Monday, an independent authority charged with investigating information provided by whistleblowers, accused the FAA of making false statements to Congress regarding the training of inspectors assessing MAX pilots.

© 2019 AFP