United States-based planemaker Boeing Co failed to submit certification documents to the US Federal Aviation Administration (FAA) detailing changes to a key flight control system faulted in two fatal crashes, a long-awaited government report has found.
The flight control system, known as MCAS, 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, according to the report seen by the Reuters news agency.
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 planemaker and FAA in the development and certification of Boeing’s top-selling aircraft.
The FAA and the IG did not immediately respond to 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 one faulting the plane’s approval, while the Justice Department has an ongoing criminal investigation.
The 737 MAX has been grounded from commercial flights worldwide since March 2019 after two crashes in a five-month span killed 346 people in Ethiopia and Indonesia.
Boeing’s so-called MCAS stall-prevention system has been faulted in both crashes after it repeatedly and forcefully pushed down the jet’s nose as pilots struggled to intervene. Crash investigators have pinpointed a cocktail of other factors.
The inspector general’s report details activities from the early phase of the certification process in January 2012 through the second crash and details allegations of “undue pressure” from Boeing management on workers handling safety certification. 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.
Regulators in the dark
Boeing kept the FAA in the dark on significant changes to MCAS, the report said. When the FAA conducted its first-ever detailed review of the system in January 2019 – three months after the first crash in Indonesia – the resulting documentation was never finalised, the report said.
The report noted that after the Indonesia crash, the FAA completed a risk analysis which found that, if uncorrected, the 737 MAX would lead to 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 the MCAS software that would include additional safeguards against unintended activation of the system.
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 the proposed software upgrade for MCAS, a second plane crashed in March 2019 in Ethiopia.
‘Too deferential to Boeing’
The FAA is currently evaluating the MCAS upgrades during a series of certification test flights this week that could pave the way for the jet’s return domestically by year-end.
“While we have not found any evidence of an inappropriately close relationship between FAA and Boeing to date, some FAA personnel expressed concern that FAA executives are too deferential to Boeing,” the report said.
In response to the report, the Transportation Department said the FAA’s certification of the 737 MAX was “hampered by a lack of effective communication” between the agency and the US planemaker.
Crucially, that included the “incomplete understanding of the scope and potential safety impacts” of the changes Boeing made to the jet’s flight control system to give it more power and authority, the agency said.
“Key FAA certification engineers and personnel responsible for approving the level of airline pilot training were unaware of the revision to (MCAS),” the report said.