A Boeing engineer who last year lodged an internal ethics complaint alleging serious shortcomings in development of the 737 Max has written to a U.S. Senate committee asserting that systemic problems with the jet’s design “must be fixed before the 737 Max is allowed to return to service.”
The letter to the Senate, a copy of which was obtained by The Seattle Times, was written by engineer Curtis Ewbank, a 34-year-old specialist in flight-deck systems whose job when the Max was in early stages of development involved studying past crashes and using that information to make new planes safer.
His letter, sent earlier this month, argues that it’s not enough for Boeing to fix the flawed Maneuvering Characteristics Augmentation System (MCAS) that’s known to have brought down the aircraft in two crashes in Indonesia and Ethiopia.
“I have no doubt the FAA and lawmakers are under considerable pressure to allow the 737 Max to return to service as quickly as possible and as soon as the public MCAS flaw is fixed,” Ewbank told the Senate.
“However, given the numerous other known flaws in the airframe, it will be just a matter of time before another flight crew is overwhelmed by a design flaw known to Boeing and further lives are senselessly lost.”
He goes on to suggest similar shortcomings in the flight-control systems may affect the safety of Boeing’s forthcoming 777X widebody jet.
Ewbank’s letter also reveals that he has been interviewed about his concerns by the FBI, which suggests his allegations have at least been considered as part of the Justice Department’s probe into what went wrong on the 737 Max and whether the actions of anyone at Boeing were criminal.
He mentions he has also delivered details of his allegations to the lead investigator on the U.S. House Committee on Transportation, chaired by Rep. Peter DeFazio, D-Ore.
In 2014, during early work on the Max’s development, Ewbank worked unsuccessfully to have Boeing upgrade the Max’s flight-control systems by adding a new data measurement system called Synthetic Airspeed that would have served as a check on multiple sensors. If it had been implemented, he believes it might have prevented the fatal crashes.
Ewbank’s original internal ethics complaint, first reported last October by The Seattle Times, alleged that Boeing rejected his safety upgrades because of management’s focus on schedule and cost considerations and the insistence that anything that might require more pilot training would not be considered.
He also alleged that Boeing pushed regulators at the Federal Aviation Administration (FAA) to relax certification requirements for the airplane, particularly in regard to the cockpit systems for alerting pilots that something is wrong inflight.
Those systems on the Max have been under scrutiny because during the two fatal Max crashes that killed 346 people, pilots struggled to understand the cascade of warnings in their cockpits.
Ewbank’s letter to the Senate Committee on Commerce, Science, and Transportation was sent June 5, ahead of a public hearing Wednesday that featured scathing criticism of FAA Administrator Stephen Dickson for his agency’s lack of progress in addressing the lapses of oversight in certifying the Max.
Ewbank criticizes not only Boeing for its design of the Max but also the FAA for approving the design without proper oversight.
“The 737 Max’s original certification was accomplished with hand-waving and deception to hide the numerous ways the 1960s-era design of the 737 does not meet current regulatory standards,” he wrote.
And he hit out at a recent Department of Transportation (DOT) advisory panel report on the Max crashes that recommended only minor changes to the way airplanes are certified, preserving Boeing’s central role in that process. Ewbank called the report “a serious threat to aviation safety and the flying public.”
“If the FAA was truly regulating in the public interest, it would take action against Boeing for its continued deception and gross errors in the design and production of the 737 Max by withdrawing Boeing’s production certificate,” he concluded.
Ansley Lacitis, deputy chief of staff for Democratic Sen. Maria Cantwell of Washington, said her office “was made aware of the letter right before the hearing” on Wednesday.
“The first step of a whistleblower investigation is to make contact with the whistleblower and we have done that,” Lacitis said. “We take these and other allegations seriously and continue to investigate them.”
In a statement, Boeing said company officials have not seen the letter.
“Boeing offers its employees a number of channels for raising concerns and complaints and has rigorous processes in place that ensure complaints receive thorough consideration and protect employee confidentiality,” the statement said. “Boeing does not comment on the substance or existence of such internal complaints.”
Boeing’s statement adds that “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.”
Ewbank could not be reached for comment.
After the Seattle Times made public his internal ethics complaint, Boeing placed Ewbank on leave. “We can confirm that Mr. Ewbank remains an employee in good standing,” company spokesman Bernard Choi said this week.
One conclusion of the DOT report on the Max crashes was that if the 737 Max had been certified as an all-new jet instead of as a derivative of the earlier model, it “would not have produced more rigorous scrutiny ... and would not have produced a safer airplane.”
Ewbank calls this “utterly incorrect.”
He cites specific regulations for which Boeing, because the Max was considered a derivative model, didn’t have to meet the latest safety standards. And he points to how these shortcomings could have affected the pilots in the two crashes.
He wrote that because Boeing, for certification purposes, had to evaluate only flight-deck systems that had changed from the 737 NG model, Boeing missed the opportunity to evaluate pilot reaction times.
Boeing has admitted that it made incorrect assumptions about those reaction times in designing the new system — the MCAS — that brought down both Max planes that crashed.
Although MCAS was new, its operation depended on other unchanged systems and its interactions with those systems were not analyzed, Ewbank wrote.
By choosing to certify the jet as an amended version of the earlier model, Boeing “severely limited the range of human factors evaluation of 737 Max systems,” he said.
And in a comment on Boeing’s forthcoming large widebody jet, Ewbank added: “The changed/unchanged system line on the 777X is even more convoluted and involves more complicated systems than the 737 Max.”
Ewbank reiterates his internal critique of the crew-alerting systems on the Max, saying they failed to meet the current standards for such alerts, which are supposed to be “designed with the latest understanding of human factors to present information to flight crews and prompt appropriate reaction in critical scenarios.”
“These flaws were known to Boeing as it worked with the FAA to certify the 737 Max, and awareness of this was creatively hidden or outright withheld from regulators,” he wrote.
Ewbank also revisits his unsuccessful push to have Synthetic Airspeed added to make the Max safer, which would have made more reliable the various air-data measures used by the flight-control computer, including the angle of attack, the angle between the jet’s wing and the oncoming air stream.
It was a faulty angle of attack reading on each of the crash flights that initiated the operation of MCAS.
“The known unreliability of air data, due to the potential for erroneous data caused by external factors, makes the initial design of MCAS simply unacceptable” Ewbank wrote. Yet, he says, “upper management shut down the (Synthetic Airspeed) project over cost and training concerns.”
According to a person familiar with the discussions, the FAA and Boeing, along with the European air safety regulator EASA, are discussing various system “enhancements” that Boeing could add to the Max after it returns to service, with no firm decisions yet made.
Last week, on the specialist aviation website The Air Current, Jon Ostrower reported that Synthetic Airspeed or an equivalent system is one of the enhancements under consideration. Boeing would not confirm that.
Michael Stumo, whose daughter Samya died in last year’s Max crash in Ethiopia, on Thursday also received a copy of Ewbank’s letter.
“This is the most comprehensive engineering analysis I’ve seen yet,” Stumo said. “It calls into question whether the Max should ever fly again.”
Ewbank notes that he left Boeing in 2015 “in protest of management actions to rationalize the poor design of the 737 Max. I did not think I could do my duty as an engineer to protect the safety of the public in the environment created by management at Boeing.”
He asserts that, “Prior to my departure in 2015, my manager argued against the design changes I wanted to make by stating, ‘People have to die before Boeing will change things.’”
Ewbank returned to Boeing in 2018 to work on the 777X.
“I returned to the company and quickly witnessed the nightmare of the very accidents I had tried to prevent happen in real life,” he writes.
After the second Max crash in Ethiopia, he filed his internal ethics complaint.
Ewbank concludes his letter to the Senate by calling for a series of actions to improve the rigor of the airplane certification process, particularly in his area of expertise: flight-deck systems.
He asks that FAA regulations be thoroughly revamped “to ensure they reflect a modern understanding of computer technology and human-machine interfaces.”
He calls for a shift in the way certification work on new airplanes is delegated by the FAA to Boeing itself and how the flow of information between the two is restricted.
“The decision to sign off on any particular design at Boeing has been culturally expropriated from the engineers to management,” he wrote.
In this critique, he mirrors criticism by the Senate committee itself, which this week proposed legislation to tighten controls on the FAA’s delegation of work and ensure direct communication between FAA and Boeing technical experts on certification details.