FAA Urges Airlines To Inspect Another Boeing 737 Model For Mid-Air Door Blowout Risks

Boeing shares fell in premarket trading in New York following the Federal Aviation Administration's announcement on Sunday recommending airlines to inspect another variant of the Boeing 737 for faulty mid-exit door plugs. This development occurred weeks after an incident where a door detached from an Alaska Airlines flight.

"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," the FAA wrote in a statement. 

The 900ER is an older aircraft not part of the Max family. Data from the plane manufacturer shows 505 of these planes are used by US domestic airline carriers and others worldwide. Major operators of the plane include United Airlines Holdings, Alaska Airlines, and Delta Air Lines.

In a separate statement, the FAA said some 900ER operators have "noted findings with bolts" during inspections. Other operators include Indonesia's Lion Air, El Al, and Korean Air. 

United's fleet of 136 900ERs will undergo "proactive inspections" early this week. 

There is no evidence so far that 900ER mid-exit door plugs have any problems or defects. This is a precautionary measure by the FAA following the Max 9 plug door that ripped off Alaska Airlines flight 1282 on Jan. 5. 

"Inspections of the Max 9 plug door can take up to eight hours and the visual checks required by the FAA for the 900ER are specific to four locations where a bolt, nut and pin installation is used to secure the door to the airframe. The detail of the work suggests stripping back the door plug to its bare frame to undertake the checks," Bloomberg said. 

Boeing shares have tumbled as much as 19.5% since the Alaska Airlines incident. Shares are down 2% in premarket trading.

Boeing said in a statement that it "fully supports the FAA and our customers in this action."