The National Transportation Safety Board (NTSB) said Tuesday that four bolts meant to help secure the door plug of a Boeing 737 Max 9 jet were missing before an Alaska Airlines flight experienced a midair blowout last month.
NTSB investigators have been looking into what may have led to last’s month incident when a fuselage panel on the Boeing 737 Max 9 aircraft blew off minutes after taking off from Portland, Ore. The federal investigators released their preliminary report Tuesday, about a month after the midair accident.
The report detailed the NTSB’s findings into the fuselage panel, which is called a door plug, after investigators dissembled it in their laboratory. The fuselage panel was recovered in Oregon after falling 16,000 feet from the Alaska Airlines flight.
The report included a photo from Boeing, taken in September 2023, that investigators say shows that three of the four bolts on the door were missing. The location of the fourth bolt is covered by insulation in the photo.