During inspections, Boeing found Foreign Object Debris (FOD) in the fuel tanks of certain 737 MAX that were stored while waiting to be delivered to customers.

"During maintenance operations, we discovered foreign object debris in undelivered 737 MAX aircraft that we are storing," a company spokesperson told AFP, adding "this finding led to a solid internal investigation and immediate corrective actions in our production chain."

The total number of affected aircraft was not disclosed. More than four hundred Boeing 737 MAX planes are currently being stored in several facilities across the United States. Boeing has also recommended for airlines that have received the 737 MAX to carry out inspections.

The inspection of the fuel tanks should not delay the recertification of the model by the U.S. Federal Aviation Administration. The authority was notified of the problem.

Mark Jenks, Vice President and General Manager of the 737 program and Renton site, deemed the presence of FOD as “absolutely unacceptable”. “One escape is one too many,” he said in a message to his employees, that listed several new measures taken to curb the issue.

Production issues have affected Boeing in the past years. Boeing’s final assembly line of North Charleston in South Carolina, opened on November 12, 2011, has been at the center of interrogations regarding quality.

In November 2019, John Barnett, a former quality control engineer said that the ramp-up of the production output of the Boeing 787 Dreamliner in 2017, after Boeing had failed to meet delivery deadlines, forced employees to disregard certain procedures, including tracking of the parts installed on the aircraft. Barnett even claimed that parts meant for scraps were installed on aircraft to be delivered and that up to a quarter of the oxygen systems installed on the Dreamliners may be defective. The U.S. planemaker denied the accusation.

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A former Boeing employee claims that up to a quarter of the oxygen systems installed on Boeing 787 Dreamliner may be defective. The U.S. planemaker denies the accusation.
 

In early 2019, the deliveries of another Boeing aircraft, the KC-46 Pegasus refueler, were suspended twice by the United States Air Force after FOD and loose tools were discovered in closed compartments of the delivered aircraft. A Corrective Action Plan (CAP) was issued and deliveries have since resumed.

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Once again, the United States Air Force has suspended taking delivery of new Boeing KC-46 Pegasus tanker jets after foreign object debris (FOD) were discovered inside the aircraft.