New York (AFP)

The 737 MAX crisis worsened on Friday, the US Air Force regulator accusing Boeing of hiding important documents, including an exchange between employees revealing that the automatic system, the MCAS, which was supposed to prevent the plane from leaving in dive, made it difficult to fly in simulator.

In this instant messenger chat that dates back to 2016, a year before the 737 MAX certification, Mark Forkner, a Boeing pilot at the time, was telling a colleague about the MCAS: "It's a shambles in the sim (the simulator, editor's note) ".

"Well I'll let you know that I'm bad at driving, but that was outrageous," the pilot continued in this conversation with a colleague, Patrik Gustavsson.

The latter pointed out that the instructions in the flight manual should be updated.

"Basically, that means I lied to the regulators (unknowingly)," Mr. Forkner replies, to which his colleague adds, "it was not a lie, no one told us that was like that.

MCAS has since been implicated in the crash of an Ethiopian Airlines 737 MAX, which crashed on 10 March southeast of Addis Ababa just minutes after take-off, killing 157 people on board.

He is also pointed out in the crash, on October 29, 2018, of a 737 MAX of Lion Air having made 189 dead.

The 737 MAX, which had been approved and authorized to fly in May 2017 by the FAA, has since been grounded around the world and uncertainties surrounding its return to service.

- Sanctions -

Late last night (Thursday), Boeing alerted the Department of Transport to the existence of instant messages between two Boeing employees, discussing some elements of communication with the FAA during the initial certification of the 737 MAX in 2016. denounced Friday the Federal Aviation Agency.

"Boeing told the department that he discovered these documents several months ago," lamented the regulator, who told Boeing boss Dennis Muilenburg to explain.

"I'm waiting for your explanation immediately about the contents of this document and why Boeing has delayed disclosure to its safety regulator," Steve Dickson, an FAA official, wrote in the letter. by AFP.

The regulator, who had in particular given Boeing the inspection of the MCAS during the certification process according to sources close to the case, promised to take sanctions.

"The FAA is reviewing the information (contained in the documents) to determine what appropriate action to take against Boeing," says the regulator, whose proximity to Boeing has been denounced from all sides since the accidents.

"This raises serious questions," reacted to AFP an industrial source. "Why were these exchanges hidden, were we trying to hide them, Boeing is in a mess," she added.

These revelations "complicate the decisions of the management which must (now) determine who is responsible (...) but it is not totally clear if it will necessarily affect the re-certification of the MAX", considers for its part Richard Aboulafia, expert at Teal Group.

Dennis Muilenburg, who has been flying Boeing since July 2015, has recently been removed from his role as chairman of the board, a decision that has sparked rumors about his possible dismissal in the coming months.

In a brief statement on Friday, Boeing simply assures that he will continue to collaborate in a House Committee inquiry: "We will continue to follow the instructions of the FAA and other regulators around the world, that we are working to revolve the 737 MAX safely. "

On Wall Street, this information caused a decline of 6.65% of the Boeing action around 18H50 GMT, investors fear that the rise in tone between Boeing and its main regulator does not affect the future of the 737 MAX, which represents more two-thirds of Boeing's order book.

© 2019 AFP