A Boeing pilot behind the 737 MAX certification in 2016 told a colleague a key flight handling system was "running rampant" during simulator tests, according to documents reviewed Friday by AFP.
The Boeing employees quipped about problems during simulations of the Maneuvering Characteristics Augmentation System, a flight-handling mechanism that is believed to be at the center of two MAX crashes that killed 346 people.
Boeing's chief technical pilot of the 737, Mark Forkner, said the MCAS system's performance during the simulator tests was "egregious" and that "I basically lied to the regulators (unknowingly)," according to the instant messages.
Forkner's lawyer, David Gerger, told AFP Saturday, "If you read the whole chat, it is obvious that there was no 'lie.'
Based on everything Mark knew, he thought the real plane was safe."
"I understand that Boeing discovered the document in its files months ago. I expect your explanation immediately regarding the content of this document and Boeing's delay in disclosing the document to its safety regulator."
A Boeing spokesman said Muilenburg called Dickson to respond to "the concerns raised in his letter" and to assure the agency that the company is "taking every step possible to safely return the MAX to service."
We will continue to cooperate with the Committee, and all other authorities, as they move forward with their investigations."
Maria Cantwell, the senior Democrat on the Senate Commerce Committee, said regulators "must receive full cooperation and all relevant documents so a full and thorough investigation can take place," adding that the reports about the messages and the lack of timely disclosure are "deeply troubling."