Missing bolts caused Alaska Airlines Boeing crash

Four of the bolts securing the panel of the Alaska Airlines Boeing 737 MAX 9 that exploded in flight in early January were missing, according to a preliminary investigation released Jan. 6.
The National Transportation Safety Board's initial report on the incident said the lack of damage or deformation around the holes "indicates that the four bolts that prevent the (door) stopper from moving upward were missing before the stopper moved upward from the restraining pads."/BGNES