Following are edited excerpts from
a current NPR report:
The Federal Aviation Administration is recommending that airlines visually inspect the door plugs of more Boeing planes after a similar panel blew off a jet in midair earlier this month.
The safety alert issued late Sunday recommends that airlines operating Boeing's 737-900ER jets inspect the door plugs "as soon as possible" to make sure they're properly secured after some airlines reported unspecified issues with the bolts.
The 737-900ER is not part of Boeing's newer Max series, but it has the same optional door plug design as the Boeing 737 Max 9, according to the FAA.
The newer jets have been grounded since Jan. 5, when a door plug blew off a 737 Max 9 plane operated by Alaska Airlines. That plane had only been flying for a few months, according to investigators at the National Transportation Safety Board.
The Boeing 737-900ER model has over 11 million hours of operation and about four million flight cycles, according to the FAA.
Boeing delivered roughly 500 of the 737-900ER planes between 2007 and 2019.
None have experienced significant problems with their door plugs, according to the FAA.The FAA's safety alert says some airlines have "noted findings with bolts during the maintenance inspections" of their 737-900ER planes but doesn't elaborate on what the findings were. The agency says it continues to evaluate data involving the mid-cabin door plug, and may order additional actions if necessary.
Alaska Airlines, United Airlines and Delta Air Lines all said they have begun checking the door plugs on their fleets of 737-900ER planes. None of the carriers said they expect any disruption to their operations.
Regulators are still studying the data from initial inspections of 40 Max 9 jets while they work to develop final inspection instructions for the planes. The FAA says safety, not speed, will determine when the Max 9 can fly again.
And more on this from The Guardian:The Federal Aviation Administration has drawn another jet into focus: the 737-900ER. Late on Sunday, the agency recommended airlines “visually inspect mid-exit door plugs” on the jet. While the 900ER is not part of Boeing’s newer Max fleet, it has an identical mid-exit door plug design. Some operators had “noted findings with bolts” during additional checks on the 900ER, the FAA said, providing no further detail.
Unlike the Max 9, which is a relatively new plane, the 900ER is well established. Boeing delivered the first one in 2007, and the last in 2019. There are some 490 in service, according to Cirium data. The 900ER, like the Max 9, has an optional door plug design which allows carriers to add an extra emergency exit door, if they install more seats. At least 79 900ER jets are estimated to be configured in this format, with a door rather than a plug.
In an alert for operators on Sunday, the FAA recommended “as an added layer of safety” that airlines check the four locations where the door is secured to the airframe of the 900ER “as soon as possible”.
Alaska, United and Delta Air Lines operate the majority of the 737-900ERs with door plugs. Each carrier said in a statement they had been inspecting their respective fleet, and did not anticipate disruption to passengers.
The National Transportation Safety Board chair Jennifer Homendy said last week the investigative agency would be looking at numerous records related to the door plug.
She said it is unclear if the bolts on the Alaska Airlines jet were properly secured or if they were actually installed at all.Analysts have called into question whether executives at the company will have to resign. “We believe the Max-9 issue will only put further pressure on Boeing management, as these incidents reflect less than expected progress on improving execution in the wake of the initial Max grounding and Covid slowdown,” Ronald Epstein of Bank of America wrote last week. “Aside from results of the NTSB and FAA investigations, regulators will likely look for more change from within Boeing.
“We would not be surprised to see regulators, investors and customers push for a turnover in the ranks of senior management and the Board of Directors.”
Reuters contributed reporting
Note: Italic emphasis in the above reports was added. 
