Boeing faces a fresh backlash over the manufacture and certification of its 737 Max following the release of internal messages by workers revealed concerns about the aircraft and attempts to conceal these from the US regulator.

Aircraft manufacturer Boeing released more than 100 pages of documents detailing the messages on Thursday as US House and Senate committees continue to probe the design and certification of the Max.

MoreNew Boeing 737 Max flaw reported as American Airlines agrees compensation deal

Boeing suspends troubled 737 Max production

Last year ‘among safest’ for commercial aviation

In one of the most-damning exchanges, a Boeing employee described the Max as “designed by clowns, supervised by monkeys”.

The aircraft remains grounded following two fatal crashes in October 2018 and March 2019.

The aircraft was certified in early 2017, but the messages date back to 2013. In April 2017, one Boeing worker slammed the Max’s “piss poor design”.

Crucially, the documents appear to confirm Boeing did all it could to convince the FAA no simulator training was required for pilots to fly the 737 – ignoring the concerns of its employees.

Boeing made this a key selling point, claiming that pilots qualified to fly earlier versions of the 737 did not need training on a simulator to fly the Max.

Simulator training can be expensive – especially in pilots’ time – and can be enough to persuade an airline to choose one type of aircraft over another.

In February 2018, one Boeing worker wrote: “Training programmes shouldn’t be taken with a pinch of salt. Would you put your family on a Max simulator trained aircraft? I wouldn’t.” Another employee responded: “No.”

Another exchange revealed an employee stating: “I want to stress the importance of holding firm that there will not be any type of simulator training required to transition [to the Max].

“Boeing will not allow that to happen. We’ll go face to face with any regulator who tries to make that a requirement.”

Workers on the Max were clearly troubled. One wrote in May 2018: “I would really struggle to defend [the simulator] in front of the FAA.”

Another suggested: “I haven’t been forgiven by God for the covering up I did last year.”

A third said, in March 2018: “I am not lying to the FAA. Will leave that to the people who have no integrity.”

Boeing only reversed its position on simulator training for pilots learning to fly the Max on Tuesday of this week.

Peter de Fazio, Democratic chairman of the House committee on transportation which is investigating Boeing, said: “These newly released emails are damning.

“They paint a deeply disturbing picture of the lengths Boeing was apparently willing to go to in order to evade scrutiny from regulators, flight crews and the flying public, even as its own employees were sounding alarms.”

The FAA has still to recertify the 737 Max as safe to fly.

In a statement, the FAA said there was nothing in the documents it was not already aware of and nothing “pointed to any safety risks that were not already identified”.

It added: “Any potential safety deficiencies identified in the documents have been addressed. The FAA remains focused on following a thorough process for returning the Boeing 737 Max to passenger service.”

Boeing said in a statement that the messages “do not reflect what we are”.

“We regret the content of these communications and apologise to the FAA, Congress, our airline customers and to the flying public.”

The crisis cost former Boeing chief executive Dennis Muilenburg his job in December. His successor David Calhoun was due to takeover as president and chief executive on January 13.

Calhoun was Boeing chairman until December and has been on the Boeing board since 2009.

MoreTravel Weekly Insight Annual Report 2019-20 – ‘forty-seven million reasons to be confident in 2020’