The Federal Aviation Administration is urging airlines to inspect door panels on another type of Boeing 737 jet, weeks after a door plug blew out mid-air on an Alaska Airlines flight.

In a statement issued Sunday, the FAA said it is recommending that airlines that operate Boeing 737-900ER jets "visually inspect mid-exit door plugs to ensure the door is properly secured." 

While the Boeing 737-900ER has been in use for nearly two decades, the FAA said it has the same door plug design as the Boeing 737 Max 9 jet involved in the Alaska Airlines' mid-air incident.

Alaska Airlines said it has already started inspecting its fleet of 737-900ER planes. "Our foundational value is safety. Accordingly and out of an abundance of caution, we began inspecting our Boeing 737-900ER aircraft several days ago," the carrier told CBS News. "We have had no findings to date and expect to complete the remainder of our -900ER fleet without disruption to our operations."

United  also said it is inspecting its jets, saying, "We started proactive inspections of our Boeing 737-900ER aircraft last week and expect them to be completed in the next few days without disruption to our customers."

In a statement to CBS News, Boeing said, "We fully support the FAA and our customers in this action."

The Alaska Airlines flight was a Boeing 737 Max 9 jet, part of a line of aircraft that was first introduced in 2016 and that has been plagued with safety issues. Door plugs are panels that cover unneeded exit doors, essentially turning them into another window. 

Following the incident, United Airlines and Alaska Airlines, which both operate Boeing 737 Max 9 aircraft, said they found loose bolts on door plugs on several of their grounded jets.

In response to the Alaska Airlines incident, U.S. regulators have grounded 171 jets from the 737 MAX 9 fleet with the same configuration as the plane involved in the incident. The FAA said it would return the 737-9 MAX to service once their safety was verified.

—With reporting by CBS News' Kris Van Cleave and AFP.

In:
• Boeing
• Alaska Airlines
• United Airlines