Boeing 737 MAX planes grounded over electrical issue

A new electrical issue with the troubled Boeing 737 MAX aircraft grounded dozens of planes this week.

The much-maligned 737 MAX returned to American airspace in late December, but dozens of planes will now sit idle after the electrical problem was discovered, the Associated Press reported.

Boeing alerted 16 airlines to the issue, including four major U.S. companies, according to the AP. Southwest, United, American and Alaska Airlines combined to pull 67 of their 133 total 737 MAX planes.

The number of jets grounded worldwide is not yet clear.

The problem affects a backup power control unit and is not related to the flight-control software that caused two crashes that killed 346 people, the Washington Post reported. It was created by a manufacturing error.

Federal Aviation Administration officials grounded all 737 MAX planes in March 2019, following the crash of Lion Air Flight 610 in Indonesia in October 2018 and the crash of Ethiopian Airlines Flight 302 five months later.

Boeing said it doesn’t know how long it will take to fix the electrical problem.