06:15 AM EDT, 06/25/2025 (MT Newswires) -- Boeing ( BA ) failed to provide sufficient training and instruction to prevent the door plug blowout of a new 737 MAX 9 operated by Alaska Airlines (ALK) in January of last year, the National Transportation Safety Board said Tuesday.

The US air safety regulator said Boeing's ( BA ) Business Process Instruction "lacked the clarity, conciseness, and ease of use necessary to be an effective tool for workers in the manufacturing process." The NTSB said the company's on-the-job training was "insufficient."

The NTSB also said the Federal Aviation Administration's compliance and audit procedures failed to identify the issues with Boeing's ( BA ) instructions for parts removals.

The NTSB issued recommendations for corrective measures to both Boeing ( BA ) and the FAA.

Boeing ( BA ) did not immediately respond to MT Newswires' request for comment.