Instant messages between two high-level Boeing employees in 2016 indicate the company was aware of major problems with an automated feature on the 737 Max jet that has been implicated in two deadly crashes.

The messages, between two top pilots, were about an automated feature known as the Maneuvering Characteristics Augmentation System (MCAS) that investigators say repeatedly — and in error — forced down the noses of planes that crashed in Indonesia and Ethi­o­pia, killing 346 people.

In the messages, Mark A. Forkner, then chief technical pilot for Boeing’s 737, wrote to technical pilot Patrik Gustavsson that the MCAS was engaging “itself like craxy,” calling the problem “egregious.”

Forkner, who had a major role in the Max, also indicated that the Boeing employees misled the Federal Aviation Administration. “So I basically lied to the regulators (unknowingly),” he wrote.

“It wasn’t a lie, no one told us that was the case,” Gustavsson replied.

The messages show the company experts had identified critical safety concerns with the Max years ago, even as Boeing executives have publicly argued since the crashes on Oct. 29 and March 10 that the company had followed the same internal practices and FAA certification procedures that have long produced safe airplanes.

Boeing did not turn the messages over to the Transportation Department until Thursday, federal officials said. The document “containing statements by a former Boeing employee” was given to Congress on Friday, Boeing said in a statement.

In a letter to Boeing chief executive Dennis Muilenburg on Friday, FAA Administrator Stephen Dickson said: “I expect your explanation immediately.”

The FAA said in a statement that it “finds the substance of the document concerning. The FAA is also disappointed that Boeing did not bring this document to our attention immediately upon its discovery.”

The flurry of messages between the pilots came over a 10-minute stretch in 2016 as the company was working with the FAA to obtain the safety certification needed to sell the Max in the United States and around the world. The new plane was critical to Boeing’s plans to compete with rival Airbus. The FAA granted Boeing the coveted certification in March 2017.

A copy of the message chain was given to the Justice Department in February in connection with the criminal probe into the Max, according to Richard Cullen, an attorney at McGuire Woods representing Boeing.

Cullen said the document was produced properly and in a timely fashion “to the appropriate agency.”

A separate set of emails from Forkner to FAA officials, in which the Boeing executive often assumed a familiar or chummy tone, showed an active company effort to remove references to the MCAS from the Flight Crew Operating Manual.

“I noticed a few things that should be changed,” Forkner wrote to one FAA official in 2017. “Delete MCAS, recall we decided we weren’t going to cover it in the” Flight Crew Operating Manual since it is “way outside the normal operating envelope,” meaning what pilots would typically face.

A report released last week by a group of international and U.S. aviation safety experts found the decision to remove the reference to the MCAS in that document meant the FAA board that considers requirements for preparing pilots “was not in a position to adequately assess training needs.”

Investigators have noted that assumptions that pilots could immediately handle an MCAS problem proved deadly.

In a 2016 email, Forkner told an FAA official he was “doing a bunch of travelling through the next few months” and that he would be “jedi-mind tricking regulators into accepting the training that I got accepted by the FAA etc.”

Boeing said Friday it “will continue to cooperate” with an investigation by the House Transportation Committee and “we will continue to follow the direction of the FAA and other global regulators, as we work to safely return the 737 Max to service.”

In a call to Dickson on Friday, Muilenburg told the administrator that the company is “taking every step possible to safely return the Max” to the air, Boeing said.

Forkner moved to Southwest Airlines last year. Gustavsson was promoted to Boeing’s 737 chief technical pilot in 2018, according to a LinkedIn listing. Boeing did not answer a question about Gustavsson’s current role.

The existence of the instant messages was first reported by Reuters.

Rep. Peter A. DeFazio, chairman of the Transportation Committee, said the message chain showed “Boeing withheld damning information from the FAA.”

“This exchange is shocking, but disturbingly consistent with what we’ve seen so far in our ongoing investigation,” DeFazio (D-Ore.) said, pointing to “a lack of candor with regulators and customers.”

“This is not about one employee; this is about a failure of a safety culture at Boeing in which undue pressure is placed on employees to meet deadlines and ensure profitability at the expense of safety,” DeFazio said.

In a letter to Transportation Secretary Elaine Chao on Friday, DeFazio said the “jedi-mind tricking” email and others showed “an improper coziness between the regulator and the regulated,” and added that it was “outrageous” and “unacceptable” that the FAA had not previously provided his committee with those and other requested emails months ago.

Forkner set the tone early in the 2016 messages, writing: “I’m locked in my hotel room with an ice cold grey goose, I’ll probably fire off a few dozen inappropriate emails before I call it a night.”

Gustavsson asked if Forkner had accomplished anything in the flight simulator. “Or what is the normal chaos there?” he wrote.

Forkner joked about what would happen if they no longer worked together and said, if Gustavsson left Boeing, “I’d ask for a job in sales where I can just get paid to drink with customers and lie about how awesome our airplanes are.”

The MCAS was “running rampant” in the simulator, Forkner wrote.

The feature was supposed to compensate for design changes and help make the 737 Max feel the same in the air for pilots used to earlier models of the 737. It would achieve that by automatically adjusting the way the plane was flying by moving the horizontal stabilizer on the plane’s tail. The stabilizer makes the aircraft ascend or descend.

The National Transportation Safety Board last month described how, in the run-up to the Oct. 29 crash in Indonesia, the MCAS automatically pushed the plane’s nose down “more than 20 times” in a six-minute stretch before it plunged into the Java Sea. Investigators say faulty data from a sensor caused the feature, which had been made increasingly powerful over the course of the airplane’s development, to repeatedly misfire.

In the message chain, the technical pilots talked about how the plane, in more than one simulated scenario, was aggressively adjusting how much it was heading either up or down, a process known as “trimming.” Pilots often do that manually, but the MCAS does it automatically in certain cases.

“I’m levelling off at like 4000 ft, 230 knots and the plane is trimming itself like craxy. . . . I’m like, WHAT?” Forkner wrote.

“that’s what i saw on sim one, but on approach . . . I think thats wrong,” Gustavsson responded. He later said they needed to ask colleagues “to confirm what its supposed to be doing.”

“Vince is going to get me some spreadsheet table that shows when it’s supposed to kick in. . . . why are we just now hearing about this?” Forkner asked.

“I don’t know, the test pilots have kept us out of the loop,” Gustavsson wrote, before clarifying that one colleague “is trying to work with us, but she has been too busy.”

They were “all so damn busy, and getting pressure from the program,” Forkner wrote.

“That is true, I wouldnt want to be them,” Gustavsson wrote.

The 737 Max has been grounded since March, shortly after the second crash in Ethi­o­pia. Boeing has been working on a software fix for the MCAS and other problems discovered as part of the recertification process.

It is unclear when the plane will be cleared by the FAA to resume service.