Boeing announced Tuesday its plan to implement design changes aimed at preventing future mid-air cabin panel blowouts, like the one experienced by an Alaska Airlines 737 MAX 9 in January.
The announcement was made at the opening session of a two-day hearing conducted by the National Transportation Safety Board (NTSB) on Tuesday to examine the MAX 9 events, Reuters reported.
Investigations have revealed that the door plug on the Alaska MAX 9 was missing four essential bolts.
Boeing, which has pledged significant quality improvements, faced rigorous questioning at the hearing about the MAX 9's production and the lack of documentation for the door plug removal.
NTSB Chair Jennifer Homendy criticized Boeing's safety culture and questioned why improvements had not been made sooner. "The safety culture needs a lot of work," she said.
In response, Elizabeth Lund, Boeing's senior vice president for quality, said that design changes are in progress and expected to be implemented within the year, followed by a fleet-wide retrofit.
"They are working on design changes that will ensure the door plug cannot be closed if there are any issues until it's securely fastened," Lund said.
The NTSB released 3,800 pages of factual reports and interviews from the ongoing investigation.
At the hearing, testimonies of workers involved in the Boeing 737 Max production were read out, which revealed they felt pressured to work too quickly, leading to mistakes.
An assembler installer testified that the demanding workload at Boeing's factory contributed to errors. Another worker reported frequent rework on planes during assembly due to problems, such as the need to fix rivets near the door plug.
The said worker also noted a lack of specialized training for handling door plugs compared to regular doors. "We were replacing doors like we were replacing our underwear," they said.
"The planes come in jacked up every day."
A Spirit employee described the challenging work environment, likening themselves to "cockroaches of the factory."
Tuesday's session also heard from a flight attendant, who recounted the terror during the blowout: "There was a loud bang and lots of whooshing air. Masks came down, and I saw the galley curtain get sucked towards the cabin."
Doug Ackerman, Boeing's vice president of supplier quality, reported that Boeing has 1,200 active suppliers for its commercial airplanes and 200 supplier quality auditors.
Lund said that Boeing is currently producing "in the 20s" of MAX aircraft per month, significantly below the 38 per month allowed. "We are gradually increasing production, but at one point, we were down to as low as eight," she told the NTSB.
The hearings are focusing on critical issues, including 737 manufacturing and inspections, safety management, quality management systems, FAA oversight, and specifics regarding the door plug operations.
