WASHINGTON - Fatal crashes of Boeing’s 737 Max were a “horrific culmination” of engineering flaws, mismanagement and oversight lapses, a US the Democratic majority on the House Transportation and Infrastructure Committee said in a report on Wednesday.

The report, which condemns both Boeing and the Federal Aviation Administration for safety failures, concludes an 18-month investigation based on interviews with two dozen Boeing and agency employees and an estimated 600,000 pages of records.

Over more than 200 pages, the Democrats argue that Boeing emphasized profits over safety and that the agency granted the company too much sway over its own oversight.

Two crashes, in Indonesia in October 2018 and in Ethiopia in March 2019, killed 346 people aboard Boeing’s 737 Max and led to the worldwide grounding of the plane.

The congressional report identified five broad problems with the plane's design, construction and certification.

First, the race to compete with the new Airbus A320neo led Boeing to make production goals and cost-cutting a higher priority than safety, the Democrats argued.

Second, the company made deadly assumptions about software known as MCAS, which was blamed for sending the planes into nosedives.

Third, Boeing withheld critical information from the F.A.A. Fourth, the agency’s practice of delegating oversight authority to Boeing employees left it in the dark.

And finally, the Democrats accused F.A.A. management of siding with Boeing and dismissing its own experts.