Boeing chairman and chief executive Dennis Muilenburg on Wednesday reiterated his projection that, despite concerns publicly expressed by Europe's air safety regulator, the 737 Max should begin to return to service around November.
However, he conceded that lack of alignment among international regulatory bodies could mean that the grounded jet may first resume flying in the United States, with other major countries following later.
"We're making good, solid progress on a return to service," Muilenburg said, speaking at a Morgan Stanley investor conference in Laguna Beach, Calif. He later added that "a phased ungrounding of the airplane among regulators around the world is a possibility."
A week ago, the European Union Aviation Safety Agency (EASA) publicly criticized the certification process of the 737 Max. And the agency said that it would favor a redesign of the airplane's systems to take readings from three independent Angle of Attack sensors rather than the two-sensor system in Boeing's proposed upgrade to the Max.
Muilenburg played down the possibility that this could mean potentially expensive hardware changes to the airplane in addition to the planned software upgrade.
Referring to the fact that the Airbus A320 – the direct competitor to the 737 – has three Angle of Attack sensors, Muilenburg said that "our architecture on Boeing airplanes is different than Airbus airplanes," and added "that doesn't necessarily mean hardware changes."
He said the concern over the level of redundancy in the Angle of Attack system could also in some cases be addressed "with simulation work, software updates or process updates."
Muilenburg said the lack of alignment among air safety regulators internationally "creates timeline uncertainty."
But he assured his audience that the FAA will go forward with its own decision on the Max, free of any political motives and based on its own assessment of the plane's safety.
"When the FAA is confident that the certification steps have been completed, that the airplane is safe, that we've answered all the questions, then they intend to proceed," he said.
Muilenburg said the software update to the flight control system that went wrong on the two Max crash flights in Indonesia and Ethiopia – called MCAS (Maneuvering Characteristics Augmentation System) – was completely wrapped up midyear and has been tested.
To satisfy regulators, he said, Boeing then went beyond that and is completing "a holistic, systemwide evaluation and update to the Max." That's what turned up a different potential vulnerability in the flight control computer discovered in June that spurred a major change to the Max's overall systems architecture: It will now compare data inputs on both of the jet's flight computers rather than using only one on each flight, as had been the case until now.
"That's the work we are wrapping up," Muilenburg said.
He also said that Boeing has developed "an enhanced computer-based training module" to update pilots on all the changes before they fly the Max again. Boeing has resisted calls for pilots to be required to train in a full flight simulator before they can fly the plane again, though that remains a possibility overseas if foreign regulators demand it.
Muilenburg said the FAA's Joint Operations Evaluation Board will make the final determination on pilot training requirements and will bring in flight crews from around the world to fly a Max simulator with the newest software and to evaluate Boeing's proposed training package before the jet's return to service is authorized.
Touching briefly on other matters, Muilenburg dismissed the importance of last week's accident during a ground test of the forthcoming 777X, when a cargo door blew out as the plane was being stress tested.
During what's called the static test of an airplane that is intended for ground test only, the wings of the plane were bent upward and the passenger cabin was overpressurized. For an airframe design to be approved for certification, the plane has to hold together without the wings breaking or other structural damage until the loads on it are at least 150% of what could be experienced in the most extreme conditions of normal flight.
Last Thursday, during the final minutes of the test inside the Everett factory, at approximately 99% of the final test loads, a cargo door exploded outward.
"That's not unusual for a static test. This is testing the airplane well beyond anything you'd ever see in operation, to test it to its very limits," Muilenburg said. "There's nothing there that will significantly affect the airplane's design."
He also addressed the current tensions in world trade and their impact on Boeing.
Muilenburg said that the lack of a trade deal between the U.S. and China is creating a risk to Boeing's widebody jet production schedule.
"We have reserved slots in the 787 and 777 production for Chinese orders," he said. "There is a dependency there on Chinese orders coming through."
He said the current production rate of the 787 Dreamliner at 14 jets per month can only be maintained if China orders more.
"We are assuming Chinese orders" in that production schedule, he said.
Still, it was the 737 Max crisis and its potential impact on the company's future that dominated Muilenburg's appearance. Muilenburg repeated his view that he sees it as "a real defining moment for Boeing."