FAA investigating if Boeing failed to ensure certain aircraft were safe for operation after door blew on Alaska Airlines plane

The Federal Aviation Administration on Thursday said it has informed Boeing that it's investigating whether the company failed to ensure that certain "products conformed to its approved design and were in a condition for safe operation in compliance with FAA regulations."

The probe comes less than a week after a panel blew out of a 2-month-old Boeing 737 Max 9 jet during an Alaska Airlines flight that was flying at 16,000 feet.

The FAA grounded Boeing's 737 Max 9 planes less than a day after that Alaska Airlines flight so the jets could be inspected. Alaska and United Airlines have said their initial checks found loose hardware on other planes of the same type.

The National Transportation Safety Board, which is leading the accident investigation, is focusing on why the door blew out during the flight. There were no serious injuries, and no passengers were seated in the two seats next to the panel.

The FAA, in a letter Thursday to a quality assurance official at Boeing, outlined the manufacturer's responsibility to ensure the aircraft conforms to design and is in safe condition.

"The above-described circumstances indicate that Boeing may have failed to ensure its completed products conformed to its approved design and were in a condition for safe operation in accordance with quality system inspection and test procedures," John Piccola, an aviation safety official at the FAA, said in his letter to Boeing.

Boeing said in a statement, "We will cooperate fully and transparently with the FAA and the NTSB on their investigations."

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