737 Max engineer didn’t know details of flight control system

By Dominic Gates / The Seattle Times

In testimony to congressional investigators probing the fatal crashes of two 737 Max jets, Michael Teal, the chief engineer on Boeing’s 737 Max program who signed off on the jet’s technical configuration, said he was unaware of crucial technical details of the flight control system that triggered inadvertently and caused the crashes.

And under questioning, both Teal and Keith Leverkuhn, the vice president in overall charge of the Max development program, denied the airplane had any design flaws beyond an assumption that the pilots would have reacted differently to the triggering of the system.

These two top executives on the Max program, accompanied by Boeing lawyers, were interviewed separately in May by investigators from the U.S. House transportation committee. Transcripts of the interviews, copies of which were obtained by The Seattle Times, are expected to be made public this week when the final report of the House investigation is due to be released.

Teal, vice president and chief project engineer during development of the Max, said he was not aware that the errant flight control software that brought down the two jets — the Maneuvering Characteristics Augmentation System (MCAS) — was triggered by a single sensor.

He learned that only after the first crash, Lion Air flight JT610, he said, “Most likely through the press.”

He was also unaware that the system could activate repeatedly, as it did in the crash flights, relentlessly pushing down the noses of the jets each time the pilots pulled them up.

“I had no knowledge that MCAS had a repeat function in it during the development,” Teal told investigators. “The technical leaders well below my level would have gone into that level of detail.”

Likewise, only “when it showed up in the press” later, did Teal learn that a warning light that was supposed to tell pilots if two angle of attack sensors disagreed wasn’t working on most Maxs, including the two that crashed — even though Boeing engineers had discovered this glitch in August 2017, more than a year before the first accident.

And Teal, who said he “signed off on the configuration of the airplane to include the MCAS function,” couldn’t recall any discussion of the decision to remove all mention of MCAS from the pilot flight manuals.

Leverkuhn also said he knew nothing of these key details about the flawed flight control system and said there was minimal focus on MCAS at his level.

“MCAS is a revision of a software in the flight control computers,” Leverkuhn said. “It really wasn’t considered, to my understanding, new or novel.”

In the interviews, which were first reported Saturday by The Wall Street Journal, the two also addressed criticisms beyond the failure of MCAS: that Boeing chose to retain the earlier 737NG model’s flight deck and not upgrade the Max’s pilot instruments to more modern regulatory standards; and that it mandated only minimal training for pilots transitioning to the Max from the NG.

Both executives insisted these decisions were not driven by cost considerations.

Instead, said Leverkuhn, making the Max and NG so similar that little training would be needed, with no time in a flight simulator, was a matter of safety.

“We knew that flight crews were going to be potentially flying an NG in the morning and then flying a Max in the afternoon,” Leverkuhn said. “So for safety reasons, we wanted the Max to have as close as possible to the same look and feel of the NG.”

“Knowing that the NG had a terrific safety record, terrific maintenance record, we knew that that airplane was familiar and ubiquitous throughout the world,” he added.

Teal echoed this: “To me, this is a safety conversation,” he said. “It’s not about the dollars and cents.”

Both executives insisted that the Max design and development program followed Boeing’s regular process and that, as Teal put it, “there’s no reason to believe that those processes were flawed at that time.”

Teal repeated the line about Boeing having followed its tried and true processes so often in the interview that he conceded, “I sound like a broken record.”

Both men defended the Boeing process and insisted the only error made was the engineering assumption that the pilots would have reacted differently when MCAS began swiveling the horizontal tail and pushing down the nose of each jet.

Teal — now chief engineer on Boeing’s next new plane, the 777X — said Boeing would learn from this error for future airplane designs.

“I am not going to discuss whether or not the process is what was the cause of the accidents,” Teal said, then added in awkwardly cold phrasing: “I will acknowledge with you that we have had a learning. Unfortunately, we’ve had two learnings.”

When Leverkuhn was asked if, in light of the two crashes and the fact that the Max has been grounded for 18 months, he would consider the Max’s development a success, he responded: “Yes, I would.”

“I do challenge the suggestion that the development was a failure,” Leverkuhn insisted.