Boeing internal documents released on Thursday show that its employees mocked US aviation regulators and bragged they could get the 737 MAX certified with minimal training for pilots.
The communications, made public by US lawmakers, include exchanges among Boeing test pilots that speak of problems with flight simulators reproducing actual flight conditions, the company said.
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The documents could further worsen Boeing's relations with regulators as it works to get the grounded jetliner back in operation.
"I still haven't been forgiven by God for the covering up I did last year," one employee wrote in a message from 2018 in reference to dealing with the Federal Aviation Administration (FAA).
"I know but this is what these regulators get when they try and get in the way. They impede progress," another wrote in August 2015.
"This airplane is designed by clowns, who in turn are supervised by monkeys," said yet another employee in 2017, apparently in reference to the FAA.
"Would you put your family on a MAX simulator trained aircraft? I wouldn't," a Boeing employee wrote to a colleague in another exchange.
"No," the colleague answered.
SEE: '737 MAX could be "phased" back into service by regulators' - Boeing CEO
The emails and text messages were made public by US lawyers investigating the certification of the 737 MAX, which was involved in two crashes that killed a total of 346 people in late 2018 and early 2019.
"Some of these communications relate to the development and qualification of Boeing's MAX simulators in 2017 and 2018," Boeing said in a statement. The company said it sent them to lawmakers in the interest of transparency.
The mocking tone of the messages is yet another embarrassment for Boeing amid the 737 MAX crisis and worsens its already relations with the FAA. The plane has been grounded worldwide since March 13.
Probes of the two crashes have focused in particular on the Maneuvering Characteristics Augmentation System, an automated flight control system.
Boeing is now working on changes to that system demanded by the FAA.
In late December Boeing pushed out its embattled chief executive, Dennis Muilenburg, because of tensions with the FAA and replaced him with board chairman David Calhoun.
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