Weeks after a door plug flew off a Boeing 737 Max 9 jet mid-flight, the company is facing a new safety alert over earlier models of 737 jets.
"As an added layer of safety, the Federal Aviation Administration (FAA) is recommending that operators of Boeing 737-900ER aircraft visually inspect mid-exit door plugs to ensure the door is properly secured," said the FAA in a press release.
The Boeing 737-900ER is not part of the Max 9 fleet, but the FAA said that model has the exact same door plug design.
"As part of their Safety Management Systems, some operators have conducted additional inspections on the 737-900ER mid-exit door plugs and have noted findings with bolts during the maintenance inspections," said the FAA in its new Safety Alert for Operators (SAFO).
All Boeing Max 9 aircraft have been grounded since the incident earlier this month, which traumatized passengers and prompted an emergency landing. Federal regulators say the aircraft will stay grounded until they can be proven safe for passengers.
In an update to the Max 9 grounding, the FAA said it is investigating Boeing's manufacturing practices and production lines, bolstering its oversight of the company, and examining potential system change.
Agencies reviewing production and maintenance of Boeing Max 9 planes
The NTSB is discussing the safety of the flying public weeks after the Alaska Airlines incident, when a door plug in a Boeing 737 Max 9 jet blew open.