Aviation Professionals Express Concerns Regarding 737 Max Door Plug Design
Aviation experts raise concerns over the structural integrity of the Boeing 737 Max 9, following an alarming incident on an Alaska Airlines flight The recent blowout of a section has sparked questions about the design of the aircraft's door plug
Following last week's in-flight emergency on an Alaska Airlines flight, aviation experts are raising concerns about the structural design of the Boeing 737 Max 9. During the January 5th flight, a "door plug" - a section of the plane's fuselage that can be used in place of an emergency exit door - became detached from the aircraft and was found in a backyard in Oregon.
According to CNN interviews, experts suggested that if the door plug had been larger and installed inside the plane, it could have been forced against the interior frame and prevented the Alaska Airlines flight incident. However, some argued that this design might have elevated costs and practical issues. "It doesn't make sense to me why they would do it that way and not have it installed from the inside, where it literally cannot come out unless there is a structural failure in the airframe," said David Soucie, a former FAA safety inspector and CNN analyst.
Soucie mentioned that the design of the door plug on the Max 9 could offer certain benefits, such as facilitating easier access for maintenance on the aircraft.
Aviation consultant Robert Ditchey concurred, suggesting that if the plug had been designed to be larger than the hole in the fuselage and installed inside the cabin, it is probable that this incident would have been prevented.
Ditchey suggested that the plug should have been installed from the inside to the outside, rather than the reverse. He expressed concern that the exterior installation could have led to the failure of the securing bolts. "There is a possibility of missing or incorrect bolts, or the bolts may have been over-torqued, causing them to break, or possibly not torqued enough," he stated.
John Goglia, a former member of the National Transportation Safety Board, stated that while an alternative design could in theory prevent such incidents, he deemed the current design sufficient if proper installation and quality controls are maintained.
"If you were to create a plug door for this aircraft that would prevent such incidents, the answer is yes, it can be done. However, it would require a significant investment of money and time," he commented. "The real question is whether the current design was adequate, and if it was installed correctly, we wouldn't be discussing it."
Goglia stated that the door would not be a significant issue if it was properly secured. A Boeing spokesperson refused to comment on the door-plug design due to an ongoing investigation by the National Transportation Safety Board. During a company-wide meeting, Boeing's CEO attributed the incident to a "mistake," without specifying further details. A company source revealed that Boeing believes the error was introduced in the aircraft's manufacturing supply chain.
Boeing CEO David Calhoun expressed his confidence in the Federal Aviation Administration's ongoing inspection of airplanes during an interview with CNBC. He stated that he is sure that each aircraft is being thoroughly inspected to ensure that they adhere to the proven design. According to CNN, federal investigators are still trying to determine why a door plug came loose on an Alaska Airlines flight, despite identifying the components involved. NTSB's Clint Crookshanks explained at a news conference that the door plug, which is typically secured in place by stop fittings and bolts, somehow moved, causing concern.
Boeing 737 Max 9 aircraft have been temporarily grounded by the FAA while the cause of the incident is under investigation. The order affects approximately 171 planes. According to former Transportation Inspector General Mary Schiavo, who is now a CNN analyst, door plugs have been utilized in aviation for a long time, including on planes that have been converted to freighters. However, she also raised concerns about the specific design of the Max 9.
She stated that the door plug used on certain Max 9s is "specifically designed to not function as a wedge-door that can't be opened when pressurized... It's a door that can only be opened from the outside during certain inspections."
"That's the aspect of the design that, in my opinion, appears to be flawed," Schiavo commented.
Schiavo believes that the incident on Friday will result in airlines implementing additional protocols for inspecting door plugs. In a separate matter, investors in Spirit AeroSystems, the supplier of the fuselage for Boeing's 737 Max jets, filed a federal lawsuit last year, alleging "widespread and sustained quality failures" in the company's products.
Boeing placed Spirit on probation from 2018 to at least 2021 due to alleged quality failures like debris in products, missing fasteners, and peeling paint, according to the suit reported by The Lever. The suit also alleges that Spirit's culture prioritized production numbers and short-term financial outcomes over product quality, leading to constant quality failures. Additionally, Spirit is accused of failing to hire sufficient personnel to deliver quality products at the rates demanded by Spirit and its customers, including Boeing. The suit does not specifically mention door plugs.
The lawsuit alleges that a previous quality manager and inspector at Spirit AeroSystems, who remains unnamed, submitted an ethics complaint to the company in 2022 detailing an "excessive amount of defects" in the products. The individual contends that "Spirit treats moving products down the line as more important than quality," according to the lawsuit. In response, Spirit AeroSystems spokesperson Joe Buccino stated that the company "strongly disagrees with the assertions made by plaintiffs in the amended complaint and intends to vigorously defend against the claims. Spirit will not comment further as to the pending litigation."
Boeing declined to comment on the lawsuit. In April, Spirit AeroSystems found a production issue on the aft fuselage section of specific 737 models. The company stated, "This is not an immediate safety of flight issue. We have processes in place to address these types of production issues upon identification, which we are following."
In August, the company revealed that there were improper holes drilled on the "aft pressure bulkhead" of certain models of the 737 fuselage. Both Spirit and Boeing released statements indicating that the issue was not considered an immediate flight safety concern.
In December, Boeing requested that airlines inspect their 737 Max jets for a potential loose bolt in the rudder system after a problem was discovered. Boeing reported that a plane with a missing bolt had been repaired but they wanted all Max planes currently in service to be checked.
Boeing has come under intense scrutiny following two fatal crashes involving 737 Max 8s – one in Indonesia in October 2018 and the other in Ethiopia in March 2019 – which resulted in the deaths of 346 people. The safety system known as MCAS, utilized in these aircraft, has been associated with both incidents.
