Systemic failures led to a door plug flying off a Boeing 737 Max, NTSB says

An NTSB investigation over the past 17 months found that bolts securing what is known as the door plug panel were removed and never replaced during a repair.

Boeing and Spirit AeroSystems — the company that made and installed the door plug — are redesigning them with another backup system to keep the panels in place even if the bolts are missing, but that improvement isn't likely to be certified by the FAA until 2026 at the soonest.

And the NTSB has found bigger problems.

"An accident like this only happens when there are multiple system failures," Homendy said.

Both Boeing and the FAA have improved training and processes since the incident, according to the NTSB, but board officials said both organizations need to better identify manufacturing risks to make sure such flaws never sneak through again. Homendy did single out Boeing's new CEO, Kelly Ortberg, for improving safety since he took over last summer, though she said more needs to be done.

The NTSB is expected to approve several recommendations at Tuesday's meeting. It already highlighted how Boeing needs to ensure that everyone throughout the company understands its safety plan as well as executives do.

The FAA must also step up to make sure its audits and inspections focus on key areas based on past problems, according to the safety board.

The blowout aboard Alaska Airlines flight 1282 occurred minutes after it took off from Portland, Oregon, and created a roaring air vacuum that sucked objects out of the cabin and scattered them on the ground below along with debris from the fuselage. Seven passengers and one flight attendant sustained minor injuries, but no one was killed. Pilots were able to land the plane safely back at the airport.

Oxygen masks dropped and phones went flying

The accident occurred as the plane flew at 16,000 feet (4,800 meters). Oxygen masks dropped during the rapid decompression and a few cellphones and other objects were swept through the hole in the plane as 171 passengers contended with wind and roaring noise.

The first six minutes of the flight to Southern California's Ontario International Airport were routine. The Boeing 737 Max 9 was about halfway to its cruising altitude and traveling at more than 400 mph (640 kph) when passengers described a loud "boom" and wind so strong it ripped the shirt off someone's back.

"We knew something was wrong," Kelly Bartlett told The Associated Press in the days following the flight. "We didn't know what. We didn't know how serious. We didn't know if it meant we were going to crash."

The 2-foot-by-4-foot (61-centimeter-by-122-centimeter) piece of fuselage covering an unused emergency exit behind the left wing had blown out. Only seven seats on the flight were unoccupied, including the two seats closest to the opening.

NTSB member J. Todd Inman said the Alaska Airlines accident would have been worse if it had happened over the ocean and far from land, but the carrier had already restricted the plane used for flight 1282 to overland flights because of an unresolved maintenance issue with a fuel pump. The airline took that step on its own, going above FAA requirements, Inman said.

Missing bolts put the focus on Boeing's manufacturing

The panel that blew off was was removed at a Boeing factory so workers could repair damaged rivets, but bolts that help secure the door plug were not replaced. It's not clear who removed the panel.

The NTSB said in a preliminary report that four bolts were not replaced after a repair job in a Boeing factory, but the company has said the work was not documented.

Investigators determined the door plug was gradually moving upward over the 154 flights prior to this incident before it ultimately flew off.

Boeing factory workers told NTSB investigators they felt pressured to work too fast and were asked to perform jobs they weren't qualified for, including opening and closing the door plug on the particular plane involved. Only one of the 24 people on the door team had ever removed one of these plugs before and that person was on vacation when it was done on the plane.

A Boeing door installer 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. The installer and other workers were not named in documents about the probe.

Investigators said Boeing did not do enough to train newer workers who didn't have a background in manufacturing. Many who were hired after the pandemic and after two crashes involving the 737 Max planes lacked that experience, and there weren't clear standards for on-the-job training.

NTSB staff also told the board that Boeing didn't have strong enough safety practices in place to ensure the door plug was properly reinstalled, and the FAA inspection system did not do a good job of catching systemic failures in manufacturing. Boeing was required to adopt a more rigorous set of safety standards after a 2015 settlement, but the NTSB said that plan had only been in place for two years before the specific Alaska Airlines plane that suffered the door plug's failure was made and that it was still being developed.

The FAA regularly conducts more than 50 audits a year on Boeing's manufacturing, but there aren't clear standards for what those audits cover. The agency routinely discarded past inspection records after five years and didn't always base its inspection plan on those past findings.

Problems with the Boeing 737 Max

The Max version of Boeing's bestselling 737 airplane has been the source of persistent troubles for the company since two of the jets crashed, one in Indonesia in 2018 and another in Ethiopia in 2019, killing a combined 346 people.

Investigators determined those crashes were caused by a system that relied on a sensor providing faulty readings to push the nose down, leaving pilots unable to regain control. After the second crash, Max jets were grounded worldwide until the company redesigned the system.

Last month, the Justice Department reached a deal allowing Boeing to avoid criminal prosecution for allegedly misleading U.S. regulators about the Max before the two crashes.

Regulators at the Federal Aviation Administration have capped Boeing's 737 Max production at 38 jets a month while investigators ensure the company has strengthened its safety practices.

Boeing hired Ortberg last year and created a new position for a senior vice president of quality to help improve its manufacturing.

The company was back in the news earlier this month when a 787 flown by Air India crashed shortly after takeoff and killed at least 270 people. Investigators have not determined what caused that crash, but so far they have not found any flaws with the model, which has a strong safety record.