Boeing says there was “no technical slip or gap” in the 737 Max

Cutting corners can cost you.
Cutting corners can cost you.
Image: REUTERS/Lindsey Wasson
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On Boeing’s earnings call today, a question from Ron Epstein of Bank of America Merrill Lynch cut to the heart of what the world has wondered in the weeks since the Ethiopian Airlines crash that killed everyone on board.

“To the extent that you can answer this,” Epstein asked, “how did this happen?”

That the same safety issue emerged in the second 737 Max 8 crash in five months was shocking, he said: “How did this slip through the engineering organization? How did it slip through the FAA? Can you give us a feel for that? Like, I guess that’s the part that befuddles me most about this, because it doesn’t seem like there was a lot of new science going on.”

The response from Boeing CEO Dennis Muilenberg was unequivocal: “There is no technical slip or gap here.” Instead, he said, “both accidents were a series of events, and that is very common to all accidents that we’ve seen in history. “

He gave further details on some of the “events” these accidents had had in common—that both airplanes had received “erroneous angle-of-attack informations” from “multiple causes,” which in turn “activated the MCAS control laws.” Ultimately, however, both featured “actions or actions not taken that contributed to the final outcome.”

Given the ongoing investigation into these crashes, it’s not surprising that Muilenberg would be vague. The 737 plane is currently grounded as a result of these crashes. In its first-quarter earnings report, Boeing estimated $1 billion in associated costs as a result, as well as a drop of 18% in earnings from operations.

Even so, there’s evidence to suggest that he may not be entirely correct—particularly about whether a “technical slip or gap” needed to be remedied.

In a much-shared article in the industry publication IEEE Spectrum, pilot and software developer Gregory Travis wrote a damning indictment of the 737 disaster, and how Boeing’s design shortcuts played a role in recent tragedies. Over time, he explained, the Boeing 737 was redesigned again and again to seat more passengers, resulting in significant problems of aerodynamics. “Instead of going back to the drawing board and getting the airframe hardware right,” writes Travis, “Boeing relied on something called the ‘Maneuvering Characteristics Augmentation System,’ or MCAS.”

By trying to mask bad hardware with software, Boeing seem to have set themselves up for failure—especially since the software was far from perfect. “The software relied on systems known for their propensity to fail (angle-of-attack indicators) and did not appear to include even rudimentary provisions to cross-check the outputs of the angle-of-attack sensor against other sensors, or even the other angle-of-attack sensor,” Travis explains. “None of the above should have passed muster. None of the above should have passed the ‘OK’ pencil of the most junior engineering staff.”

This analysis casts doubt on Muilenberg’s view that “no technical slip or gap” had taken place—and does a much better job of answering how this “series of events” happened in the first place.