Newly-disclosed documents "appear to point to a very disturbing picture" about Boeing's response to safety issues regarding the 737 MAX, a US congressional aide told AFP Tuesday.

Boeing sent the documents "late in the evening" Monday just hours after ousting Dennis Muilenburg as chief executive, according to the aide with the US House Transportation Committee.

The committee is leading the probe into the MAX, which has been grounded since March following two deadly crashes, including Boeing's response to the first crash and the role of regulators overseeing the certification of the aircraft.

The aide declined to release the papers and said committee aides were still reviewing the documents.

"The records appear to point to a very disturbing picture of both concerns expressed by Boeing employees about the company's commitment to safety and efforts by some employees to ensure Boeing's production plans were not diverted by regulators or others," the aide said in an email.

The panel is led by Democratic Representative Peter DeFazio, who grilled Boeing executives at an October hearing at which some lawmakers called for Muilenburg to resign.

DeFazio on Monday called Muilenburg's ouster "long overdue, and said the company "made a number of devastating decisions that suggest profit took priority over safety." Boeing announced that it was replacing Muilenburg with Chairman David Calhoun, saying the company needed to "restore confidence" and "repair relationships with regulators, customers and all other stakeholders."