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.