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Boeing 'kept regulator in the dark over key changes to 737 Max's flight-control system'

Telegraph reporters
The Boeing 737 Max has been grounded since March 2019 - REUTERS

Boeing failed to submit certification documents to the US Federal Aviation Administration (FAA) detailing changes to a key flight control system that has been blamed for two fatal crashes, a long-awaited government report seen by Reuters has found.

The 737 Max has been grounded from commercial flight worldwide since March 2019 after two crashes killed 346 people in Ethiopia and Indonesia over a five-month span.

Boeing's flight-control system, known as MCAS,  has been faulted in both crashes, when the system repeatedly and forcefully pushed down the jet's nose as pilots struggled to intervene. Crash investigators have pinpointed a cocktail of other factors.

According to the report, the system was "not an area of emphasis" because Boeing presented it to the FAA as a modification of the jet's existing speed trim system, with limited range and use.

The 52-page report by the US Department of Transportation's Office of Inspector General (IG), dated June 29 and set to be made public on Wednesday, laid bare mistakes made by both the manufacturer and FAA in the development and certification of Boeing's top-selling aircraft.

157 people died in Ethiopia in 2019 when a Boeing 737 Max came down a few minutes after take-off - GETTY IMAGES

The FAA declined to comment beyond the department's response attached to the report. The IG did not immediately respond to Reuters for a request for comment.

A Boeing spokesman said the company had taken steps to enhance safety and was committed to transparency. "When the Max returns to service, it will be one of the most thoroughly scrutinised aircraft in history, and we have full confidence in its safety," he said.

The IG's report is the latest of reports faulting the plane's approval, while the Justice Department is pursuing a criminal investigation.

The report details activities from the early phase of the certification process in January 2012 until the second crash and details allegations of "undue pressure" from Boeing management on workers handling safety certification.

The report noted that after the Indonesia crash the FAA completed a risk analysis that found that the uncorrected risk to the 737 MAX was 2.68 fatalities per 1 million flight hours, which exceeded the FAA's risk guidelines of 1 fatality per 10 million flight hours.

A December 2018 FAA analysis determined a risk of about 15 accidents occurring over the life of the entire 737 MAX fleet if the software fix was not implemented.

After the crashes, Boeing proposed and FAA accepted a redesign of MCAS software that would include additional safeguards against unintended MCAS activation.

Boeing agreed to develop the software update by April 12 and operators would have until June 18, 2019, to install the software. As Boeing worked on proposed software upgrade for MCAS, a second plane crashed in March 2019 in Ethiopia.

The IG's office will issue recommendations to the FAA later this year, the Transportation Department said in comments about the draft report submitted on June 8.