WASHINGTON – For months, missing paperwork has hindered the investigation into how a door plug blew off a 737 Max on an Alaska Airlines flight in January, making it difficult to find out who made the near tragic mistake. This week, Boeing disclosed that the paperwork may have caused the problem in the first place.

It was already well known that no documentation was found to show who worked on the door plug, which came off the plane after it had reached around 16,000 feet in the air causing an uncontrolled decompression, which injured a few passengers and even tore one’s shirt off. But at a briefing for journalists at Boeing’s 737 Max factory in Renton, Washington, Boeing said that the lack of paperwork is why the four bolts needed to hold the door plug in place were never installed before the plane left the factory in October. The workers who needed to reinstall the bolts never had the work order telling them the work needed to be done.

Without the bolts, the door plug incident was pretty much inevitable. Luckily, it wasn’t fatal. It’s a sign of the problems with the quality of work along the Boeing assembly lines. Those problems have become the focus of multiple federal investigations and whistleblower revelations, and the cause of delays in jet deliveries that are causing headaches for airlines and passengers around the globe.

But Boeing may have landed itself in even more trouble with regulators for divulging the details at this stage. The National Transportation Safety Board (NTSB) reprimanded Boeing Thursday for releasing “non-public investigative information” to the media. It said in a statement that the company had “blatantly violated” the agency’s rules. “During a media briefing Tuesday about quality improvements… a Boeing executive provided investigative information and gave an analysis of factual information previously released. Both of these actions are prohibited,” the NTSB said.

Boeing will no longer have access to information generated by the NTSB during its investigation, the agency said, adding it was referring Boeing’s conduct to the Department of Justice. “As a party to many NTSB investigations over the past decades, few entities know the rules better than Boeing,” the NTSB said. (CNN)…[+]