The Federal Aviation Administration on Thursday announced it had opened an investigation into whether Boeing failed to ensure that its 737 Max 9 plane was safe and conformed to the design approved by the agency.

The F.A.A. said the investigation stemmed from an Alaska Airlines Boeing 737 Max 9 plane’s loss of a fuselage panel on Friday shortly after it took off from Portland, Ore., leaving a hole in the side of the passenger cabin. The plane returned to Portland to make an emergency landing.

“This incident should have never happened and it cannot happen again,” the agency said.

This is a developing story. Check back for updates.