Boeing 737 in Alaska Air accident was missing four bolts, say US officials

Four bolts that should have prevented a panel from flying off an Alaska Airlines jet at 16,000 feet were apparently missing, US investigators said Tuesday, fueling more scrutiny about manufacturer Boeing Co.’s ability to ensure the safety of its planes.

Photos and other evidence suggest the bolts were removed for work at Boeing’s Renton, Washington, factory and not replaced, according to a preliminary 19-page report from the National Transportation Safety Board.