Two days after the publication of a 2016 instant message chat between two senior pilots on the 737 MAX program drew outraged condemnation from members of Congress, airline pilot unions and outside experts, Boeing said Sunday the pilot text exchange had been widely misinterpreted.

In the chat conversation on Nov. 15, 2016, made public Friday by a congressional committee, 737 MAX chief technical pilot Mark Forkner told another pilot that when he’d flown the MAX in a flight simulator that day, the jet’s new flight control system behaved very erratically.

In a Sunday morning statement, Boeing insisted this doesn’t mean it had prior knowledge of the system flaws that two years later would play a major role in the two deadly crashes in Indonesia and Ethiopia. Instead, Boeing said, Forkner’s “comments reflected a reaction to a simulator program that was not functioning properly.”

Boeing said the erratic behavior in 2016 of the new flight control system in the simulator — Forkner in the chat with another pilot described the flight control system called MCAS as “running rampant in the sim” and causing the plane to move without pilot input by “trimming itself like craxy [sic]” — wasn’t a result of the flawed system design, but instead an issue with the simulator software.

“The simulator software used during the Nov. 15 session was still undergoing testing and qualification and had not been finalized,” Boeing stated.

Forkner, who left the company in July 2018, has refused to speak to Boeing, and so the company’s interpretation of what the pilot described in the chat relies on a statement from Forkner’s attorney, David Gerger.


Boeing said that “while we have not been able to speak to Mr. Forkner directly about his understanding of the document, he has stated through his attorney that his comments reflected a reaction to a simulator program that was not functioning properly.”

Forkner, in addition to declining to speak with Boeing, has refused to turn over documents to federal law enforcement officials who have subpoenaed him, citing his Fifth Amendment right against self-incrimination.

During Forkner’s chat with his fellow 737 MAX technical pilot Patrik Gustavsson, in addition to describing the erratic behavior of the flight control system, Forkner also asserted that this meant that he “basically lied to the regulators (unknowingly),” potentially putting him at risk of prosecution.

Forkner’s suggestion that he may have unknowingly lied derives from his role as Boeing’s lead pilot liaising with the Federal Aviation Administration (FAA) with regard to what training on the MAX would be required of airline pilots and what details would be in the pilot manuals. Seven months earlier, Forkner had written to the FAA asking that they not include anything in the manuals about the new flight control system, known as the Maneuvering Characteristics Augmentation System (MCAS).

“Are you OK with us removing all reference to MCAS from the FCOM (Flight Crew Operating Manual) and the training as we discussed, as it’s completely transparent to the flight crew and only operates WAY outside of the normal operating envelope,” Forkner wrote to the FAA in March 2016.

On Friday, Gerger sent a statement to The Seattle Times, which reads in full:


“If you read the whole chat, it is obvious that there was no “lie” and the simulator program was not operating properly. Based on what he was told, Mark thought the plane was safe, and the simulator would be fixed.”

This interpretation that it was the simulator program that was at fault is certainly not “obvious” from the full transcript of the messages. A person with knowledge of the matter, who requested anonymity, said Gerger previously provided Boeing with the same general explanation of his client’s comments in the messages.

Nevertheless, this is the interpretation now repeated by Boeing as it seeks to defend the company against the suggestion that it knew in 2016, or should have known, that MCAS could behave aggressively and that it misled the FAA by not disclosing this.

In both crash flights, MCAS was activated by a single faulty sensor and repeatedly pushed the nose of each aircraft down before the pilots lost control.

Boeing’s statement on Sunday also disputes earlier reports, including in The Seattle Times, that a critical design change to MCAS that occurred during flight test was not fully disclosed to the FAA. The design change entailed allowing MCAS to activate at low speeds as well as high speeds and required removing one of the system activation triggers, so that it now relied on a single sensor.

Boeing’s statement Sunday said it informed the FAA about the expansion of MCAS to low speeds, “including by briefing the FAA and international regulators on multiple occasions about MCAS’s final configuration.”

“Separately, a low-speed version of MCAS was installed on the airplanes used for training-related flight testing that the FAA administered in August 2016,” the statement adds. “And FAA personnel also observed the operation of MCAS in its low-speed configuration during certification flight testing, beginning in August 2016 and continuing through January 2017.”


Boeing’s assertion that the FAA was fully informed of this crucial design change directly contradicts the findings of an international panel of regulators — the Joint Authorities Technical Review (JATR) — released earlier this month.

That panel of experts found that as MCAS evolved starting in March 2016 “from a relatively benign system to a much more aggressive system,” it was not properly evaluated in the certification documents that Boeing submitted to the FAA.

Echoing a Seattle Times report on March 17, less than a week after the second crash, the panel found that Boeing submitted to the FAA an inadequate technical description of the airplane’s new MCAS, lacking full details of when the system activated and the extent of its power to push an airplane nose down.

Boeing’s documentation of MCAS was fragmented and incomplete, the report said.

“The JATR team identified specific areas related to the evolution of the design of the MCAS where the certification deliverables were not updated during the certification program to reflect the changes to this function within the flight control system” the report states.

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“The JATR team found that the MCAS was not evaluated as a complete and integrated function in the certification documents that were submitted to the FAA,” the report adds. “The lack of a unified top-down development and evaluation of the system function and its safety analyses, combined with the extensive and fragmented documentation, made it difficult to assess whether compliance was fully demonstrated.”


It appears that whatever information Boeing provided the FAA about the changes to MCAS did not filter down to all those who should have been aware of it.

Sources within the FAA have told The Seattle Times that key technical personnel responsible for approving certification of the MAX did not learn of the critical MCAS design changes until after the Lion Air crash.

Boeing provided the Department of Justice the transcript of the message exchange between Forkner and Gustavsson in February, the month before the second MAX crash in Ethiopia.

The Justice Department, presumably acting on a whistleblower tip, at that point had already convened a grand jury to investigate possible criminal liability after the first crash in Indonesia.

Boeing’s statement Sunday expressed regret that the Forkner instant message chat, when finally made public Friday, “could not be released in a manner that would have allowed for meaningful explanation.”

Boeing CEO Dennis Muilenburg, who recently lost his dual role as company chairman, is slated to appear before a Congressional committee on Oct. 30. The company reports its latest quarterly financial results on Wednesday.