FAA says it is investigating Boeing over Alaska Airlines' mid-air blowout

The Federal Aviation Administration said Thursday it is conducting an investigation into Boeing's 737 Max 9 aircraft following Friday's mid-air blowout of a door plug on an Alaska Airlines flight.

"This incident should have never happened and it cannot happen again," the FAA said in the statement.

The agency said the probe will examine whether Boeing "failed to ensure" whether the jet conformed to its design and whether its aircraft "were in a condition for safe operation in compliance with FAA regulations." It added that the investigation stems from the door plug's blowout and "additional discrepancies."