After two deadly crashes that killed 346 people, the beleaguered Boeing 737 Max has a new problem, and per a company spokesman, it's an "absolutely unacceptable" one. A routine maintenance check on multiple new planes waiting to be delivered turned up in their fuel tanks "foreign object debris," which the BBC notes is "any substance, debris, or article that isn't part of a plane [and that] would potentially cause damage." Per the Guardian, such debris usually consists of metal shavings, rags, tools, or other items left behind in the plane by workers during production. Leeham News, which first reported the development, notes it may take up to three days to inspect each plane, as all fuel has to be drained and the vapors eliminated before inspectors can even enter the fuel tanks to check them out.
"FOD is absolutely unacceptable," Mark Jenks, head of Boeing's 737 program, said in a memo to employees. "With your help and focus, we will eliminate FOD from our production system." The entire fleet of 400-plus undelivered 737 Max planes is now being inspected, though a Boeing rep tells the BBC it doesn't look like this will further delay getting the 737 Max back in the air; Boeing expects the FAA to recertify the plane to fly again by summer. The FAA has indeed been informed of this latest development and, via a statement, says that it's "following a thorough, deliberate process to verify that all proposed modifications to the Boeing 737 Max meet the highest certification standards," per Sky News. The fuel tank problem isn't tied to the sensor issues that are believed to have played a role in the Lion Air and Ethiopian Airlines crashes. (Problems plaguing the 737 Max may affect summer travel.)