In the Federal Aviation Administration’s investigation of the production of Boeing’s 737 Max jets, the audit revealed “dozens of problems” at the company’s facilities and one of its main suppliers.

The six-week audit was prompted by an incident in early January in which a door blew out of a 737 Max 9 jet during an Alaska Airlines flight shortly after departing Portland, Oregon. Since then, there have been a string of Boeing 737 Max 9 jet mishaps, heightening the public’s fears and frustrations with the plane-maker and leading customers and regulators alike to question the quality of the company’s planes.