The manager, Edward Pierson, said the assembly line fell far behind schedule by mid-2018 because of cascading problems that began with late delivery of key parts. Yet Boeing went ahead with its plan to boost production from 47 to 52 planes a month.
"By June 2018, I had grown gravely concerned that Boeing was prioritizing production speed over quality and safety," Pierson said during a Wednesday hearing. "I witnessed a factory in chaos and reported serious concerns about production quality to senior Boeing leadership months before the first crash" and again before the second crash.
No action was taken about his concerns, and executives didn't discuss the problems in financial reports, Pierson said.
"The bottom line is the 737 factory needs to be closely investigated," Pierson said on Wednesday afternoon.
Boeing called any links between production conditions and the crashes "completely unfounded."
"None of the authorities investigating these accidents have found that production conditions in the 737 factory contributed in any way to these accidents," the company said Wednesday. "And the suggestion of such a linkage is inconsistent with the facts that have been reported about these accidents."
Boeing hopes airlines will be able to use the plane again early next year after the company completes fixes to flight-control software and computers. Dickson has insisted that the FAA has no timetable for granting that approval.
Dickson said he has not ruled out a civil penalty and has not made a determination if Boeing's lack of transparency with the public about issues was criminal.
DeFazio praised Dickson's recent comments but was harshly critical of the agency and Boeing.
The FAA "failed to do its job. It failed to provide the regulatory oversight necessary to ensure the safety of the flying public," DeFazio said.
Published reports indicate that FAA officials knew very little about a flight-control system called MCAS that was implicated in the October 2018 crash of a Max off the coast of Indonesia and the March 2019 crash of another Max in Ethiopia. In both crashes, investigators say, a faulty sensor caused MCAS to push the nose of the plane down and pilots were unable to regain control. In all, 346 people died.
Regulators around the world ground the plane after the second crash.
FOX Business' Hillary Vaughn and The Associated Press contributed to this report.