The Federal Aviation Administration says it is opening an investigation into Boeing’s quality control after the violent in-flight failure of a door plug on a nearly new 737 Max 9.

In a new statement, the FAA says last Friday’s dramatic in-flight blowout on Alaska Airlines 1282 “should have never happened and it cannot happen again.”

The fuselage plug that blew off the aircraft Friday left a gaping hole in the side of the plane and ripped headrests off seats as the plane flew at 16,000 feet shortly after taking off from Portland, Oregon, carrying 177 people.

The FAA says the investigation will focus on whether Boeing “failed to ensure completed products conformed to its approved design and were in a condition for safe operation in compliance with FAA regulations.”