After grounding its fleet of Boeing 737 MAX 9 planes in the wake of a mid-air blowout on an Alaska Airlines jet, United Airlines has found loose bolts on multiple MAX 9 aircraft.
The bolts were discovered in door plugs similar to that which blew out during the Alaska Airlines flight.
“Since we began preliminary inspections on Saturday, we have found instances that appear to relate to installation issues in the door plug – for example, bolts that needed additional tightening,” United Airlines said in a statement.
“These findings will be remedied by our Tech Ops team to safely return the aircraft to service.”
United Airlines did not specify the number of loose bolts it found, but citing someone familiar with the matter, The Air Current reported that at least five aircraft were involved.
According to CBS News, the carrier said it expected “significant cancellations” on Tuesday as a result of the grounding, but was working on returning the jets to service as soon as possible. It added that it had already cancelled 200 MAX 9 flights.
Several airlines around the world operate MAX 9 jets, with some carriers following a Federal Aviation Authority (FAA) order to ground the aircraft until further notice.
But according to aviation data firm Cirium, Alaska Airlines and United Airlines operate nearly two-thirds of the 215 MAX 9s in service.
In an updated statement, the FAA said it had “approved a method to comply with the FAA’s Boeing 737-9 emergency airworthiness directive, and it has been provided to the affected operators”.
“The FAA’s priority is always keeping Americans safe. In that spirit, Boeing 737-9 aircraft will remain grounded until operators complete enhanced inspections which include both left and right cabin door exit plugs, door components, and fasteners,” it stated.
“Operators must also complete corrective action requirements based on findings from the inspections prior to bringing any aircraft back into service.
“The FAA will continue to support the National Transportation Safety Board’s investigation into Alaska Airlines Flight 1282.”
Plot thickens
The United Airlines discovery confirms that the issue lay not with Alaska Airlines and one plane, but could be a fleet problem.
“It was really important to figure out whether it was that specific aircraft from Friday night, whether it was an issue with Alaska Airlines’ fleet specifically or whether it’s a broader issue that could impact all MAX 9s that have that door,” Embry-Riddle Aeronautical University air safety expert Anthony Brickhouse told Reuters.
“The fact that United has now found some aircraft with loose bolts, that just means that the investigation is going to be expanded.”
Brickhouse also praised Alaska Airlines and United Airlines for doing “the right thing in grounding their fleet”.
“It just illustrates how important it was to ground similar MAX 9s and do those inspections,” he said.
“A lot of times in the industry money and profit are placed before safety. And grounding a specific aircraft isn’t a light decision. It’s a very big decision and it involves money and a lot of cancelled flights.”
On social media platform X, NTSB confirmed it had found the door plug from the Alaska plane.
“NTSB investigators are currently examining the door plug and will send it to the NTSB Materials Laboratory in Washington, DC for further examination,” it wrote.
According to ABC News, the approximately 29-kilogram plug was discovered in the backyard of a Portland teacher’s home.
The Alaska Airlines blowout occurred last Friday, shortly after flight AS1282 took off from Portland (Oregon) bound for Ontario (California).
Carrying 171 passengers and six crew, the MAX 9 jet safely returned to Portland. No one was seriously injured in the incident.
