The Federal Aviation Administration issued a recommendation Sunday for operators of Boeing 737-900ER aircraft as part of an ongoing effort to ensure the safety of the planes following a midair blowout earlier this month on a related Max 9 aircraft.
The FAA suggests operators visually inspect the 900ER planes’ mid-air exit door plugs to ensure they are properly secured.
While the 900ERs are not part of the Max 9 fleet, the FAA said they share an identical design for the part that failed on an Alaska Airlines flight. The agency noted that some 900-ER operators have reported finding bolt issues during maintenance inspections.
The FAA recommendation comes five days after the agency launched an investigation into the manufacturing practices and production lines at Boeing following the Jan. 5 incident. That investigation includes Spirit AeroSystems in Kansas, which reportedly makes 70% of the Max 9 fuselage.
The FAA investigation, and Sunday’s recommendation, are intended to bolster oversight.
The FAA grounded all Max 9s following the emergency landing of an Alaska Airlines flight that lost a panel midflight over Oregon. United Airlines, which operates the world’s largest fleet of Max 9 aircraft, reported earlier this month that it had found loose bolts on some of its fleet.
The door plugs on the 737-900ER have not experienced any failures. The FAA said it is making the visual inspection recommendation “as an added layer of safety.”
Days after the Alaska Airlines incident, the FAA said it was increasing oversight of Boeing’s production and manufacturing. It also launched an investigation into the company to determine if it failed to ensure completed products conformed to their approved design and were safe to fly.
Boeing has also increased inspections throughout its build process at its factory in Washington state as well as Spirit AeroSystems. The company’s inspections include the dispatch of an oversight group to Spirit’s facilities in Kansas to inspect installation of the door plugs that are used as plane panels in place of emergency door exits.
The National Transportation Safety Board is currently investigating the Alaska Airlines incident.
