On Thursday, factory workers will pause production for sessions on improving quality control. The FAA's boss said its investigation focuses on Boeing's quality control, not the door plug design. Nobody was seriously injured, but all 171 Boeing 737 Max 9 jets with a door plug have been grounded since. AdvertisementNEW: FAA Administrator Mike Whitaker tells me its probe of the Alaska Airlines blowout is focused on Boeing quality control issues. The 737 Max 9 door plug design is good "when properly executed," but "where we are looking now is quality assurance and quality control at Boeing."

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Persons: —, Stan Deal, CNN's Pete Muntean, Mike Whitaker, Max, Pete Muntean, Ben Minicucci, United's Scott Kirby Organizations: Boeing, Alaska Airlines, Service, Boeing Commercial Airplanes, Navy, Max, National Transportation Safety Board, Federal Aviation Administration, United Airlines, NBC Locations: Renton , Washington