The Federal Aviation Administration opened a formal investigation of Boeing¡¯s aircraft operations following last week¡¯s accident on one of its passenger jets, escalating a quality control crisis at the U.S. plane-maker.

The regulator said the company¡¯s production practices must meet demanding safety standards for which it¡¯s accountable. The investigation stems from a midair blowout of a so-called door plug on a 737 Max 9 jet operated by Alaska Airlines on Jan. 5.

¡°This incident should have never happened and it cannot happen again,¡± the agency said in a statement.