The Federal Aviation Administration (FAA) announced on January 21 that operators of the Boeing 737-900ER should visually inspect the aircraft’s mid-exit door plugs. The -900ER, the predecessor model to the 737 Max 9, shares the same door plug design.
The agency recommended the inspections as “an added layer of safety” for airlines that fly the 737-900ER. In a Safety Alert for Operators (SAFO) the agency said that “some operators have conducted additional inspections on the 737-900ER mid-exit door plugs and have noted findings with bolts during the maintenance inspections.”
Currently around 171 Max 9 jets are grounded as the agency works to establish that the door plugs are not at risk of failure after one blew out during an Alaska Airlines flight on January 5.
Major operators of the -900ER include Delta Airlines, Alaska Airlines, Lion Air, and United Airlines.