Thursday, February 29, 2024

Boeing 737 Max 9 plane that lost door plug was missing bolts, NTSB says

Four bolts were missing from a door panel that exploded during an Alaska Airlines flight last month as the Boeing 737 Max 9 plane flew over Oregon, according to a preliminary report from the National Transportation Safety Board.

The bolts are there to prevent the non-operational panel, called the door stopper, from moving upward, the NTSB said. But last year, before the plane was delivered to Alaska Airlines, the door panel had to be opened and four bolts removed at Boeing’s factory in Renton, Washington, to replace damaged rivets nearby, the report said. report.

As part of the investigation, the agency found that the “absence of contact damage or deformation” around the holes associated with the vertical movement bolts indicates that four bolts from the door panel were missing before the panel detaches stops, according to the report. .

It is unclear why the bolts were missing. Records show the rivets were replaced, but photos obtained from Boeing Co. by the NTSB show the door panel was put back in place without bolts in three visible locations. The fourth location is obscured in the photo by insulation, the NTSB said.

The photo of the door panel came from a text message between Boeing employees who were discussing “interior restoration after rivet rework during second shift operations that day,” the NTSB report said.

General view of the Boeing 737 Max 9 door plug and associated components removed from the accident aircraft as received at the NTSB Materials Laboratory. Four bolts designed to hold the door stopper in place were missing, according to a preliminary NTSB report.


Boeing said in a statement that the company would “promptly” review the NTSB’s findings and would continue to cooperate “fully and transparently” with that investigation as well as a separate investigation by the Federal Aviation Administration.

“Whatever the final conclusions, Boeing is responsible for what happened,” said the group’s chief executive, Dave Calhoun, in the statement. “An event like this should not happen on a plane leaving our factory. We simply must do better for our customers and their passengers.

Boeing said it has implemented a quality control plan to ensure that all 737 Max 9 mid-exit door plugs are installed “in accordance with specifications,” including new inspections of the door plug assembly in the factories of both suppliers as well as internally, and the addition of “signage and protocol” to fully document when the door plug is opened or removed in the Boeing factory.

The NTSB’s preliminary report released Tuesday is the latest blow to Boeing and its reputation.

The same day the report was released, FAA Administrator Michael Whitaker testified before a House subcommittee and suggested the agency may need to take a tougher approach to policing Boeing after the incident of the door panel.

“First, what’s wrong with this plane?” But second, what is happening with production at Boeing? Whitaker told a House subcommittee, according to the Associated Press. “There have been problems in the past. They do not appear to be resolved, so we feel we need to have an increased level of monitoring.

Adding to the company’s problems, on Sunday the planemaker said that main fuselage supplier Spirit AeroSystems had reported that two holes had been improperly drilled in the window frames of some 737 Max planes.

Boeing said it was finalizing “rework instructions” for the affected planes and would ensure that any planes not yet delivered to customers meet specifications.

Boeing said the problem had no “immediate impact on flight safety” and that planes could continue to operate safely.

Last week, Boeing reported a quarterly loss of $30 million, less than analysts expected for the three months ended Dec. 31, before the door jam burst. The company said it would not provide revenue guidance for this year.

“While we often use this time of year to share or update our financial and operational goals, now is not the time for that,” Calhoun said on a conference call with Wall analysts. Street. He added that he was focusing on quality control after the door jam incident.

These recent incidents come just a few years after two 737 Max 8 plane crashes in 2018 and 2019 which left 346 dead. The accidents were largely caused by a faulty automated flight control system.

Although the NTSB’s preliminary report did not reach conclusions about the causes of the door plug failure, former Boeing CEO Ed Pierson, who retired in 2018 from the aerospace giant’s 737 plant , said investigators should focus on whether there were systemic problems in Boeing’s manufacturing procedures. .

“It’s not someone missing a bolt,” he said. “It’s usually a process breakdown or simple human error. But I would say the more likely scenario is that employees feel rushed, and employees feel rushed because the company is pressuring factories to produce these planes and pumping them out the door. »

Pierson, who is also executive director of the Aviation Safety Foundation, a watchdog group, said Boeing’s promises to fix the door panel problems ring hollow because it views them as reactive rather than proactive measures.

“All of this should have happened a long, long time ago,” he said, referring to previous problems with the 737 Max line. “They get no credit for doing what they should have done years ago.”

The NTSB said its investigation into Alaska Airlines Flight 1282, which was traveling Jan. 5 from Portland International Airport to Ontario, was ongoing.

The plane’s cabin suddenly depressurized when the door plug exploded, leaving a gaping hole in the side of the plane while the plane was 16,000 feet in the air. (The door stopper was later found in a Portland teacher’s backyard.)

After the door panel was ripped off the plane, the plane made an emergency landing in Portland. Seven passengers and a flight attendant suffered minor injuries, the NTSB said. The FAA grounded all Max 9 planes for nearly three weeks after the incident.

The FAA then grounded all 171 Max 9 planes with door plugs, forcing airlines such as United and Alaska to change their flight schedules.

The FAA said Monday that United and Alaska have now inspected and returned to service nearly 94% of the Max 9 planes in both fleets, according to Reuters.

Note: The content and images used in this article is rewritten and sourced from



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