In short:
Boeing workers and executives have appeared before the US transport safety authority investigating the Alaska Airlines cabin door incident onboard a Boeing plane.
Multiple witnesses said the safety culture at Boeing was lacking, which the transport authority chair criticised.
What's next?
The two-day hearing will inform a final report to be released by the safety watchdog at a later date.
A string of safety failures and a lack of accountability were behind the Boeing Alaska Airlines door plug emergency, the US transport safety authority has heard in hearings into the incident.
Throughout a two-day hearing into the reasons behind the Flight 1282 incident, Boeing was repeatedly criticised for its lack of safety and accountability throughout the airplane production process.
Boeing factory workers gave evidence to the US National Transportation Safety Board (NTSB) saying they were pressured to work too fast and asked to perform jobs that they weren't qualified for, including opening and closing the door plug that later blew off the 737 MAX jet.
The NTSB and Boeing said officials still have not determined who removed and reinstalled that plane's door plug during production.
A Boeing door installer, who was not named alongside other workers, said he was never told to take any shortcuts but everyone faced pressure to keep the assembly line moving.
"That's how mistakes are made. People try to work too fast," he told investigators for the transport safety authority.
The panel that blew off the Boeing 737 Max on January 5 was made and installed by a supplier, Spirit AeroSystems.
It was removed at a Boeing factory so that workers could repair damaged rivets, but bolts that help secure the door plug weren't replaced.
Another member of the Boeing door crew said workers got no special training for door plugs and should not have been asked to open or close the panels.
Boeing, which has vowed to make key quality improvements, faced extensive questions about the production of the accident-hit MAX 9 and lack of paperwork documenting the removal of the door plug.
Boeing workers at the factory in Renton, Washington, have "been put in uncharted waters to do everybody's dirty work because no one wants to touch it," the second worker told investigators.
The worker described Boeing's safety culture as "garbage. Nobody's accountable".
The workers' accounts were among more than 3,000 pages of documents released by the NTSB into the accident, which left a gaping hole in the plane and created decompression so violent that it blew open the co*ckpit door.
'Chaos' but no fatalities
"It was chaos," the Alaska Airlines co-pilot told investigators about the moment the door plug blew out from the plane's fuselage.
The accident occurred minutes after take-off from Portland, Oregon, as the plane flew at 4,800 metres.
Oxygen masks dropped during the rapid decompression, and several phones and other objects were swept through the hole in the plane.
Several passengers were injured in the incident, but the aircraft landed safely with all 171 passengers and six crew on board.
A flight attendant described a moment of terror when the door plug blew out.
"And then, just all of a sudden, there was just a really loud bang and lots of whooshing air, like the door burst open," the flight attendant said.
"Masks came down, I saw the galley curtain get sucked towards the cabin."
The door plug was later found in a science teacher's backyard in Portland.
The plane had been in service for just eight weeks.
Following the incident, the plane model was grounded for two weeks, a ban on Boeing expanding production was announced by the federal aviation authority, and a criminal investigation began into the company.
Company executives called to answer
NTSB chair Jennifer Homendy on Tuesday criticised the plane maker's safety culture, asking why it had not made improvements earlier.
"The safety culture needs a lot of work," Ms Homendy said.
The plane manufacturer said it planned to make design changes to prevent future blowouts.
Boeing's senior vice president for quality Elizabeth Lund said the company hopes to implement the changes within the year and then to retrofit across the fleet.
"They are working on some design changes that will allow the door plug to not be closed if there's any issue until it's firmly secured," Ms Lund said.
Ms Lund said two Boeing employees who were likely involved in the opening of the door plug have been placed on paid administrative leave.
Doug Ackerman, vice president of supplier quality for Boeing, said the company has 1,200 active suppliers for its commercial airplanes and 200 supplier quality auditors.
Ms Lund said on Tuesday Boeing is still building less than 30 MAX planes a month — below the 38 it is allowed to produce.
"We are working our way back up. But at one point I think we were as low as eight," she told the hearing.
The hearings are reviewing key issues, including 737 manufacturing and inspections, safety management and quality management systems, federal oversight, and issues surrounding the opening and closing of the door plug.
Last month, Boeing agreed to plead guilty to a criminal fraud conspiracy charge and pay a fine of at least $US243.6 million ($371.3 million) to resolve a Justice Department investigation into two 737 MAX fatal crashes.
AP/Reuters
