Shortly after the 737 MAX jet accidents, a senior Boeing engineer filed an internal complaint that claimed company decision-makers rejected a backup system that may have been able to prevent the Ethiopian Air and Lion Air crashes.
Curtis Ewbank, a senior Boeing engineer, worked on the cockpit systems during the MAX’s development. The MAX uses angle-of-attack sensors to keep track of the plane’s position in the sky. If they malfunction, they could send faulty information to the cockpit systems. One such system was the MCAS—the anti-stall system that likely triggered the disasters. The MCAS was triggered by bad data in both downed flights, overriding the pilots’ efforts to steady the planes.
Ewbank claimed that company engineers urged management to consider installing a backup system called “synthetic airspeed” for calculating the plane’s trajectory in case the angle-of-attack sensors malfunctioned.
The synthetic airspeed system uses data from various sources to measure a plane’s position rather than relying only on the angle-of-attack sensors. That equipment could have been able to detect the malfunctioning sensors and prevent other systems, particularly the MCAS, from using inaccurate readings.
While Ewbank said it wasn’t a given that the system would have prevented the crashes, it could have. Boeing already uses synthetic airspeed in its 787 Dreamliner, so why didn’t Boeing deploy it on the MAX? Ewbank believes it came down to money.
“I was willing to stand up for safety and quality but was unable to actually have an effect in those areas,” Ewbank said. “Boeing management was more concerned with cost and schedule than safety or quality.”
According to Ewbank, a Boeing executive rejected synthetic airspeed because it would cost more to install and train pilots how to use it.
A former senior Boeing employee, who spoke anonymously due to the ongoing investigation, corroborated Ewbank’s account that Boeing executives did consider the backup system but decided that it would be too complicated and problematic to install such new technology in an aircraft based on a 1960s design, especially under such tight scheduling pressures. The employee also said Ewbank was overestimating the backup system’s impact on a 737 that used fewer sensors than the Dreamliner.
Ewbank is still at Boeing, so it couldn’t have been easy for him to make the complaint about his own employer. In his statement, he claimed he was motivated by the “ethical imperative of an engineer to protect the safety of the public.”
Read more about the MCAS at Boeing 737 MAX Pilots Had No Idea What They Were Up Against.