The embattled US aircraft maker Boeing has reportedly sent US regulators “troubling communications” related to the development of the 737 MAX – on the same day that the CEO, Dennis Muilenburg, was forced to step aside.

According to a senior Boeing executive, the documents include new messages from Mark Forkner, a senior company test pilot who complained of “egregious” erratic behavior in flight simulator tests of Boeing’s MCAS anti-stall system, and referred to “Jedi mind tricks” to persuade regulators to approve the plane.

The executive, speaking on condition of anonymity, told the Seattle Times that the Forkner communications contain the same kind of “trash talking” about Federal Aviation Authority (FAA) regulators as the earlier messages released in October.

The release is likely to deepen the sense of crisis enveloping Boeing, which has taken more than $8bn in costs and lost more than 20% of its market value since the 737 variant was grounded in March following two crashes. Last week, the company said it would temporarily halt production of the troubled jet.

Forkner, meanwhile, has reportedly hired his own criminal defense lawyers and invoked his fifth amendment right against self-incrimination to avoid turning over records to the US Department of Justice, which has opened a criminal inquiry into the company’s handling of the 737 Max’s development.

It was Forkner who requested that information about MCAS be omitted from flight manuals and pilot training, rendering the pilots of both the doomed Lion Air and Ethiopian flights helpless when the system kicked in, pushing the plane’s nose down repeatedly until they ultimately lost control.

But the timing of the latest information release is likely to increase anger surrounding Boeing’s handling of the crisis, even as a new CEO, David Calhoun, takes the reins early next year.

In a statement released on Monday, Boeing said that under the “new leadership”, Boeing “will operate with a renewed commitment to full transparency, including effective and proactive communication with the FAA, other global regulators and its customers”.

But the latest drop of documents could complicate those intentions, and further challenge its relationship with regulators.

The aerospace giant already angered the FAA by failing to turn over the Forkner messages for eight months because of the criminal investigation into how the plane was originally approved for service.

“The FAA is also disappointed that Boeing did not bring this document to our attention immediately upon its discovery,” the regulator said in a statement on 18 October.

The regulator was also reportedly further vexed by Muilenburg’s predictions that the 737 Max would imminently be cleared to return to service, which it regarded as placing pressure on the agency to approve Boeing’s MCAS software fix even as it was taking a hit to its reputation for being too cozy with the plane maker.

Dennis Muilenburg has paid with his job as Boeing’s CEO for his handling of the 737 Max crisis. Photograph: Reuters

Last month, Muilenburg was reportedly called to a meeting in Washington with the FAA administrator, Steve Dickson, and dressed down for applying perceived pressure on the regulator.

An internal FAA memo written by Dickson and reviewed by the Wall Street Journal, said the FAA would not work to any schedule. Separately, it signaled it would not allow the Max to fly again until 2020.

Muilenburg’s efforts to take responsibility for the 737 debacle, and to apologize for its tragic consequences, fell flat with lawmakers, the public and grieving families, costing him his job.

During congressional testimony, Muilenburg offered muddled responses to lawmaker’s demands for clarity on the development and approval of the 737 Max, and why it had not been immediately grounded after the first crash in Indonesia.

“You’re not trying to Jedi mind-trick us here today on this committee?” the Democrat Dina Titus challenged.

Still, Muilenburg, 55, is in line to receive $26.5m in cash and stock as part of his exit package.

His payout could reach as high as $58.5m, depending on how it is structured, according to an SEC filing, including a pension of $807,000 annually and Boeing stock worth another $13.3m.

In a statement on Monday, Boeing’s board said it had decided that “a change in leadership” was necessary to restore confidence. But it chose not to fire the executive, allowing him to keep his pay package and saving Boeing from the impression its most senior executive had done something wrong.

But according to subsequent reports, it was not just the handling of 737 Max crisis or squabbles with the FAA that ultimately doomed Muilenburg.

Last week, a high-profile launch of Boeing’s space capsule went awry.