Issue behind Boeing blowout should’ve ‘been caught years before’ - regulator

The head of the National Transportation Safety Board said on Wednesday the Alaska Airlines Boeing 737 Max 9 midair emergency was entirely avoidable because the planemaker should have addressed unauthorized production work long ago.

"This accident should have never happened. This should have been caught years before," the NTSB chair, Jennifer Homendy, told reporters on the second day of a hearing into the 5 January incident.

"There have been numerous, numerous Boeing audits, FAA audits, compliance reviews, compliance actions plans, noting a history of an unauthorized work, unauthorized removals," she said.

She added there was no guarantee the issue would not occur again.

Boeing created no paperwork for the removal of the 737 Max 9 door plug - a piece of metal shaped like a door covering an unused emergency exit - or its re-installation during production, and still does not know which employees were involved. The plug was missing four key bolts when it was delivered to Alaska Airlines, the NTSB has said.

Boeing did not immediately comment.

If Boeing had learned from prior unauthorized work, "then this would have been caught and this would have been prevented", Homendy said, adding the board is also scrutinizing the Federal Aviation Administration's oversight of Boeing.

"We have a lot of questions - there was information known," Homendy said about the FAA's oversight of Boeing, citing defects and missing and incorrect documents, as well as incorrect policies that "have been issues for years. This is not new."

Homendy has questions about FAA audit procedures and whether Boeing previously received advance notice of reviews and asked if they were too focused on reviewing paperwork.

After the incident, the FAA barred Boeing from expanding production beyond 38 planes per month and announced a 90-day review of the planemaker, and has required significant quality and manufacturing improvements before it will allow the company to hike production.

The FAA administrator, Mike Whitaker, said in June the agency was "too hands-off" in Boeing oversight. The FAA's approach before the midair accident was "too focused on paperwork audits and not focused enough on inspections", Whitaker added. The FAA has also boosted the number of inspectors at Boeing and Spirit factories.

"We will continue our aggressive oversight of the company and ensure it fixes its systemic production-quality issues," the FAA said on Wednesday.

Last week, the Senate commerce committee chair, Maria Cantwell, and Illinois senator Tammy Duckworth introduced legislation to review and strengthen safety management systems at the FAA.

Homendy said the NTSB plans to conduct a safety culture survey of employees at Boeing's Renton factory that builds the 737 Max line.