Boeing’s mid-air blowout: Bolts appeared to be missing from plane's panel that blew off, says US regulator

Bolts appeared to have been missing from a door plug that blew out midair from a Boeing 737 Max 9 operated by Alaska Airlines last month, according to an initial report by the United States safety regulator, National Transportation Safety Board (NTSB).

‘Four key bolts’

The NTSB in its report released on Tuesday (Feb 6), alongside photographic evidence providing the first official look into how the mishap might have happened, said four key bolts meant to hold the door plug in place were missing.

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The initial report comes over a month after the dramatic emergency landing of an Alaska Airlines flight due to a near-catastrophic incident where a panel known as a “door plug” blew out of the plane over the US state of Oregon.

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The panel that blew out on January 5 is used to plug an unused emergency exit.

According to the NTSB preliminary report, four bolts were removed while workers repaired damaged rivets last year at Boeing’s factory in the US state of Washington.

The report citing photographic evidence suggests that when the plug was reinstalled, at least three of the four locking bolts had not been replaced, while the location of the fourth was obscured.

According to the report, US regulators also noted that there was damage to the door plug and its hinges, but not to the areas where the bolts should have been, suggesting that the bolts were missing before the door moved out of its normal position.

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“The investigation continues to determine what manufacturing documents were used to authorize the opening and closing” of the plug “during the rivet rework,” said the report.

Boeing to review findings

Boeing, in a statement on Tuesday, said that it appreciates the NTSB’s work and “will review their findings expeditiously.”

It added that the company will also continue to “cooperate fully and transparently” with the investigations by NTSB and Federal Aviation Administration (FAA), America’s top aviation watchdog.

“Whatever final conclusions are reached, Boeing is accountable for what happened. An event like this must not happen on an airplane that leaves our factory,” said Boeing CEO Dave Calhoun.

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He added, “We simply must do better for our customers and their passengers. We are implementing a comprehensive plan to strengthen quality and the confidence of our stakeholders.”

The incident had prompted US regulators to ground Boeing 737 Max 9 aircraft, while the American planemaker has faced intense scrutiny since the incident last month.

(With inputs from agencies)