The US House Committee responsible for investigating Boeing’s 737 MAX airplanes issued their preliminary report on Friday, identifying failures on the part of Boeing and the Federal Aviation administration (FAA).

The investigation was prompted by the two fatal crashes within five months of each other, an event the House recognized as “unprecedented in modern times.”

The preliminary findings identified five themes affecting the aircraft’s design, development and eventual certification, suggesting that errors and oversight occurred in multiple places.

The findings first suggest that Boeing was under immense financial pressure to compete with a similar aircraft, leaving the designers unable to adjust to unforeseen difficulties economically or temporally. Next, Boeing falsely assumed that their pilots would be able to mitigate malfunctions resulting from their MCAS [flight control] software, which was designed to push the plane’s nose down in certain conditions. Because of this, Boeing did not classify MCAS as a safety-critical system, so it underwent less scrutiny during certification. Boeing withheld key information about the MCAS’s existence and operation from the FAA and its pilots. A conflict of interest within the FAA may have caused them to favor Boeing at the expense of the greater public’s safety interests, and the House found their review “grossly insufficient.” And, FAA management was found to overrule their own technical efforts, disregarding safety concerns to side with Boeing.

The House committee notes that these themes have recurred throughout their investigation, rather than representing isolated incidents. Overall, the report concludes that design failures, a lack of transparency and purposeful obfuscation were to blame for the deadly crashes.

While the investigation continues, the House intends to introduce legislation to reform the FAA’s certification process.