Boeing failed to submit certification documents to the Federal Aviation Administration on modifications to the 737 Max jet’s Maneuvering Characteristics Augmentation System (MCAS), including significantly increasing the system’s ability to lower the aircraft’s nose automatically under certain conditions, according to a report detailing the certification timeline released Wednesday by the U.S. Department of Transportation’s Inspector General’s (IG) office.

According to the report, FAA flight test personnel knew of the change, but “key” agency certification engineers and personnel responsible for approving the level of airline pilot training told the IG’s office they did not.

The report also revealed that because Boeing’s safety analysis did not assess system-level safety risks as catastrophic, the company’s engineers designed MCAS to rely on data from a single aircraft sensor. Although Boeing did not communicate to the FAA the formal safety risk assessments related to MCAS until November 2016 and January 2017, more than four years into the five-year certification process, FAA managers told the IG’s office that “it isn’t unusual” for manufacturers to complete and submit safety assessments toward the end of the certification process.

Meanwhile, because Boeing presented the software as a modification to the 737’s existing speed trim system that would activate only in limited conditions, the FAA did not emphasize MCAS in its certification efforts and, therefore, a more detailed review of the system did not occur between agency engineers and Boeing. Rather, the FAA concentrated its efforts on what it considered high-risk areas such as the airplane’s larger engines, fly-by-wire spoilers, and landing gear changes.

Following the start of flight testing in 2016, the FAA’s Flight Standards Service approved a training plan proposed by Boeing—known as Level B training—for 737 Max pilots already qualified to fly the Boeing 737-800. According to the IG report, the outcome met with Boeing’s “overarching” goal of gaining a common type rating for pilots moving to the Max from the NG largely because it limited costs by avoiding simulator training. Furthermore, required training did not include pilot response to automated MCAS activation, added the report.

In a statement to AIN, Boeing insisted it has committed to “complete transparency” with the FAA during the entire recertification process. Since global certification authorities grounded the Max in March 2019, Boeing has introduced three more layers of protection related to flight control software and updated flight training to account for MCAS.  “We have made robust improvements to the 737 Max flight control software, including ensuring MCAS cannot be activated based on signals from a single sensor and cannot be activated repeatedly,” said Boeing. “We have dedicated all resources necessary to ensure that the improvements to the 737 MAX are comprehensive and thoroughly tested. We have also taken a number of actions to further improve the safety culture of our company. These actions include establishing a permanent aerospace safety committee of the company's board of directors and reorganizing the company's engineering organization, with all engineers reporting up through Boeing's chief engineer. When the Max returns to service, it will be one of the most thoroughly scrutinized aircraft in history, and we have full confidence in its safety.”

In comments published in the appendix of the IG report, the FAA conceded that its oversight suffered from a lack of effective communication, not only between Boeing and the agency but within the agency itself, “which led to an incomplete understanding of the scope and potential safety impacts of changes to the flight control system.”

“FAA’s certification process relies on receiving complete, candid information from manufacturers,” the commentary read. “The agency will be taking further steps to ensure integrity and transparency with regard to information sharing, assumptions, and validation, all of which are integral to the overall certification system. Additionally, FAA anticipates strengthening coordination among the lines of business with certification responsibilities, as well as enhancing its human factors, flight controls, and system safety expertise to address weaknesses that led to an incomplete understanding of MCAS prior to certification.”