The National Transportation Safety Board (NTSB) has released its final report on the Alaska Airlines mid-air door plug blowout involving a Boeing 737 MAX 9 in January 2024. The investigation concluded that Boeing's failure to provide adequate training, guidance, and oversight in manufacturing processes, including the removal of the mid-exit door (MED) plug, was the probable cause.
The NTSB also highlighted the Federal Aviation Administration’s (FAA) ineffective compliance enforcement and audit planning as contributing factors. The FAA did not identify or ensure that Boeing addressed repetitive issues at its Renton, Washington facility where the 737 MAX is assembled.
On July 10, following weeks after publishing its executive summary and findings, the NTSB issued a comprehensive 156-page report detailing safety issues at Boeing. These included inadequate documentation for MED plug removal during assembly and ineffective workforce management. The NTSB stated that "as a result of this investigation, the [NTSB] makes 11 recommendations to the FAA and 8 recommendations to The Boeing Company."