US airplane manufacturer Boeing (BA) had a fresh setback with its fleet of grounded 737 MAX aircraft this week, after discovering debris in the fuel tanks of several of the new planes being stored for delivery to customers.
According to an internal memo seen by Reuters, the company says the debris, which was found during maintenance work in the tanks, could create safety risks. Reuters reports that Mark Jenks, general manager of the 737 programme, described the debris as “absolutely unacceptable.”
The entire 737 MAX fleet has been grounded since March 2019, after two fatal crashes — a Lion Air in October 2018 and an Ethiopian Airlines flight in March — that killed 346 people.
"While conducting maintenance we discovered Foreign Object Debris (FOD) in undelivered 737 Max airplanes currently in storage,” a Boeing spokesman said in a statement. “That finding led to a robust internal investigation and immediate corrective actions in our production system."
Foreign object debris is an industry term for any materials or substances that are not part of the plane.
The company said it does not expect the debris problem to cause any delays to getting the planes back into service in the second half of the year once the Federal Aviation Administration lifts the ban and certifies the planes for flight again.
Boeing was dethroned by European rival Airbus as the world’s biggest plane manufacturer last year. The grounding of its 737 MAX fleet has hammered airlines, who have been forced to lease planes. Tui (TUI.L), the world’s largest travel group, said this month that it will spend over €220m ($240m, £186m) leasing new planes. Meanwhile low-cost carrier Ryanair (RYA.L) said delivery delays with the 737 Max aircraft could thwart the Irish company’s goal of flying 200 million passengers a year by up to two years.