The National Transportation Safety Board (NTSB) has issued its final report on the Alaska Airlines Boeing 737-9 that lost a door plug shortly after takeoff out of Portland, Oregon, in January 2024.

Because Boeing’s instructions for employees lacked “clarity and conciseness,” workers missed opportunities to fix a mistake that nearly caused a disaster.

The NTSB on Thursday released its final report on a midair door plug blowout on an Alaska flight last year and assigned ...