Photo/Illutration A Boeing 737 Max being built for Norwegian Air International taxis for a test flight at Renton Municipal Airport in Renton, Washington, Dec. 11, 2019. (AP file photo)

WASHINGTON--Boeing Co. on Thursday released hundreds of internal messages that contained harshly critical comments about the development of the 737 MAX, including one that said the plane was "designed by clowns who in turn are supervised by monkeys."

The messages also show attempts to duck regulatory scrutiny with employees ridiculing the plane, the company, the Federal Aviation Administration and foreign aviation regulators.

In a instant messaging exchange on Feb. 8, 2018--when the plane was in the air and eight months before the first of two fatal crashes, an employee asks another: "Would you put your family on a MAX simulator trained aircraft? I wouldn't"

The second employee responds: "No."

In particular, some of the communications reveal efforts by Boeing to avoid pilot simulator training--an expensive and time-consuming process--for the 737 MAX, which has been grounded since March after the two crashes in the space of five months killed 346.

The plane maker just this week changed its tack on simulator training, saying it would recommend that pilots do the training before they resume flying the 737 MAX--a major shift from its longheld position that pilots only needed computer-based training.

The release of the messages, which highlight an aggressive cost-cutting culture and disrespect towards the FAA, is set to deepen the crisis at Boeing which is still struggling to get its best-selling plane back in the air.

The FAA said, however, that the messages do not raise new safety concerns although "the tone and content of some of the language contained in the documents is disappointing."

The disclosure, which Boeing said was in the interest of transparency with FAA, also prompted renewed outrage from U.S. lawmakers from both political parties and puts more pressure on Boeing's new CEO David Calhoun to overhaul the company's culture when he takes the reins on Monday.

House Transportation Committee Chairman Peter DeFazio, who has been investigating the MAX, said the messages "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 internally."

Boeing said the communications "do not reflect the company we are and need to be, and they are completely unacceptable."

It also said it is confident "all of Boeing's MAX simulators are functioning effectively" after repeated testing of simulators since the messages were written.

The messages, however, show Boeing in the past was doing all it could to lobby aviation regulators around the world to avoid the need for airlines to train pilots in a simulator on the differences between the 737 MAX and its predecessor the 737 NG.

"I want to stress the importance of holding firm that there will not be any type of simulator training required to transition from NG to MAX," Boeing's 737 chief technical pilot said in a March 2017 email.

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