In the first week of 2024, a Boeing 737 Max 9 passenger jet lost a rear door plug in midflight, terrifying people on board. The large door plug plummeted into the backyard of a high school science teacher in Portland, Ore. The Federal Aviation Administration ordered the grounding of similarly configured Boeing 737 Max 9 aircraft for weeks.
"This incident should have never happened and it cannot happen again," the FAA said at the time.
The news hasn't gotten much better for Boeing, whose reputation was already tarnished by deadly crashes of its 737 Max 8 jets in 2018 and 2019, and a host of problems with its 787 Dreamliner a decade ago.
Ripple effects of the door plug incident quickly hit airlines that bought dozens of new 737 Max 9 airliners only to see them idled — and then face skepticism from passengers once the aircraft were cleared.
Though commercial air travel is still very safe overall, Boeing now faces renewed questions over its ability to meet quality and safety standards. Many of the same questions also center on the FAA's oversight of Boeing and the corporation's cozy relationship with the U.S. government, from the U.S. role in helping Boeing sell planes on the international market to its status as a major employer and military contractor.
Here's a recap of Boeing's troubled year so far:
Jan. 5: Door plug failure cuts Alaska Airlines flight short
Alaska Airlines Flight 1282, a Boeing 737 Max 9, climbs to 16,000 feet after taking off in Portland, Ore. — but its rear door plug is violently expelled from the plane, with 171 passengers and six crew members aboard.
Rapid decompression sucks phones and other items out of the person-sized hole. No serious injuries are reported. The flight lasts almost exactly 20 minutes.
"We are very, very fortunate here that this didn't end up in something more tragic," National Transportation Safety Board Chair Jennifer Homendy says the next day, adding, "no one was seated in 26A and 26B, where that door plug is."
Alaska Airlines grounds its 65 Boeing 737 Max 9 aircraft; the FAA then orders a wider shutdown, affecting 171 planes overall.
Jan. 8: Airlines find more loose parts, while a lawsuit alleges "excessive amount of defects" at key Boeing supplier
Alaska Airlines and United Airlines, both of which fly Boeing jets with the door-plug configuration, say they found loose parts on their grounded 737 Max 9 jets.
Preliminary inspections "found instances that appear to relate to installation issues in the door plug — for example, bolts that needed additional tightening," United says. Alaska's maintenance crews report hardware that was visibly loose.
As the door-plug failure makes headlines, new scrutiny also comes to Spirit AeroSystems, which manufactured the fuselage and door plug on the Alaska Airlines plane.
In court filings for a shareholder lawsuit, a former Spirit quality-control inspector alleged finding an "excessive amount of defects" at its plant in Kansas. The suit also alleges that an employee was asked to obscure quality problems — and was retaliated against when he raised a red flag about defects.
Spirit was spun off from Boeing in 2005 and is led by former Boeing executive Pat Shanahan, who was tapped to right the ship last fall after its former CEO was fired.
Jan. 12: FAA says it will audit Boeing production, hints at a major shift
One day after sending the company formal notice of an investigation into whether it broke regulations, the FAA says it will audit the Boeing 737 Max 9 production line and its suppliers as the agency boosts oversight.
And in what could promise a sea change for the industry, the FAA says it's looking at clawing back some of the safety analysis work it has outsourced to plane makers — a controversial practice that has allowed Boeing and other companies to self-certify the quality of their work.
"It's something that's long overdue," David Soucie, a former FAA safety inspector, tells NPR.
Jan. 16: Apparent Boeing insider blames company for door plug
A self-described Boeing employee says the aircraft company, not Spirit, was the last to install the door plug on the 737 Max 9.
"The reason the door blew off is stated in black and white in Boeings own records," the person writes on an aviation website. "It is also very, very stupid and speaks volumes about the quality culture at certain portions of the business."
Specifically, the apparent whistleblower says, Boeing's manufacturing records show that workers failed to properly reinstall bolts meant to hold the large panel in place.
The claim was first reported by The Seattle Times, after a separate source tells the newspaper that when the plane was flagged to have some more work done on its fuselage, Boeing mechanics in Renton, Wash., reinstalled the door plug improperly.
Jan. 24: FAA clears path for 737 Max 9 to resume flying
The FAA says the grounded Boeing 737 Max 9 jets can be put back into service once they've undergone "a thorough inspection and maintenance process."
But in a new setback for Boeing, the agency also says it won't allow the company to ramp up production for any of its Max family of aircraft.
"This won't be back to business as usual for Boeing," FAA Administrator Mike Whitaker says, adding that the regulator won't let Boeing expand production until it's satisfied the company has resolved quality control issues.
Meanwhile, Boeing CEO Dave Calhoun meets with lawmakers in Washington, D.C.
"We believe in our airplanes," Calhoun tells reporters on Capitol Hill. "We have confidence in the safety of our airplanes. And that's what all of this is about. We fully understand the gravity."
Jan. 26: The 737 Max 9 flies again, but some customers balk
After three weeks, Alaska Airlines puts the first of its Boeing 737 Max 9 jets back into service. But some customers say they're reluctant to fly on the aircraft, their confidence shaken by the nightmarish incident earlier that month.
"I never paid any attention until this happened as to what I was flying in," Corrie Savio tells NPR.
As potential passengers look for ways to know what plane they'll likely be on, airlines and booking sites offer ways for customers to change planes, including omitting the Max 9 from flight search results.
Feb. 6: In preliminary report, NTSB says bolts were missing
Four critical bolts were missing from the plane whose door plug explosively blew off the Alaska Airlines flight, the NTSB says in its preliminary report. The bolts are meant to prevent the door plug from sliding upward, the agency says.
When the plane arrived at Boeing's plant near Seattle, the NTSB says, workers needed to correct a problem with its fuselage rivets — a process that requires its door plug to be opened and then closed. The NTSB says that after Spirit AeroSystems workers at the plant replaced those rivets last September, the door plug was put back on the plane without four bolts.
The NTSB does not say who was responsible for the failure to ensure the bolts were reinstalled.
"Boeing is taking immediate action to strengthen quality," the company says in response, noting it has begun new inspections for structural items such as the door plug, and adding a protocol to ensure door plugs are reinstalled properly and inspected before delivery to customers.
Feb. 21: Head of 737 Max program departs in shakeup
Boeing executive Ed Clark, who oversaw Boeing's 737 Max program and Renton, Wash., plant, leaves the company, replaced by Katie Ringgold.
Boeing also creates a new role of senior vice president of quality, naming Elizabeth Lund to the post.
Feb. 28: FAA gives Boeing 90 days to come up with a plan
The FAA tells top Boeing officials that they have 90 days to develop a comprehensive plan to address "systemic quality-control issues to meet FAA's non-negotiable safety standards."
The changes should be foundational and far-reaching — and Boeing also needs to apply a high level of rigor and oversight to its suppliers, FAA Administrator Mike Whitaker says.
"Boeing must commit to real and profound improvements," Whitaker says in a statement, adding later, "Boeing must take a fresh look at every aspect of their quality-control process and ensure that safety is the company's guiding principle."
March 4: FAA audit slams Boeing and Spirit
After a six-week audit of Boeing and Spirit, the FAA says it "found multiple instances where the companies allegedly failed to comply with manufacturing quality control requirements."
The FAA cites problems in numerous areas, including "manufacturing process control, parts handling and storage, and product control."
The agency also cites an expert review panel's report on Boeing, which found "a disconnect between Boeing's senior management and other members of the organization on safety culture." The experts, who had been working on the federally mandated review before the door-plug incident, reported speaking with Boeing employees who doubted the company's systems could ensure open communication and non-retaliation; several also said that before their interview, they were briefed by Boeing's legal department.
March 6: NTSB says Boeing isn't sharing basic details
Boeing hasn't shared key information — such as which workers were responsible for not reinstalling the door plug properly at its factory in Washington state, NTSB chair Jennifer Homendy tells the Senate Commerce Committee.
"It's absurd that two months later, we don't have that," Homendy says.
The NTSB wants details about who did the work on the door plug, and when.
"Boeing has not provided us with documents and information we have requested numerous times," Homendy tells lawmakers.
Boeing spokesman Connor Greenwood pushes back on that version of events.
"Early in the investigation, we provided the NTSB with names of Boeing employees, including door specialists, who we believed would have relevant information. We have now provided the full list of individuals on the 737 door team, in response to a recent request," Greenwood says in a message to NPR.
March 8: Boeing says it can't locate documents related to door plug
In a letter to Washington Sen. Maria Cantwell, Ziad Ojakli, Boeing's executive vice president of government operations, says employees looked "extensively" but could not find any documents on the "opening and closing of the door plug."
Ojakli also says Boeing has been transparent with the government's investigation, denying allegations that the company hasn't been fully cooperative.
March 9: A Boeing whistleblower is found dead
John Barnett, a former Boeing quality control manager who became a whistleblower, is found dead in Charleston, S.C., where he once worked at Boeing's large 787 plant.
Police are investigating after finding Barnett dead in a vehicle. The coroner's office says he died "from what appears to be a self-inflicted gunshot wound."
Barnett was locked in a yearslong legal battle with Boeing. In a whistleblower complaint filed in early 2017, he accused his former employer of retaliating against him for raising safety concerns in the company's commercial airplanes.
"He was looking forward to having his day in court and hoped that it would force Boeing to change its culture," his family says in a statement.
March 12: NTSB sets date for investigative hearing; Boeing replies to FAA audit findings
The NTSB announces plans to hold an investigative hearing on Aug. 6 and 7 about its investigation "into how and why a door plug departed" from the passenger jet during flight.
The hearing will be livestreamed, featuring investigators, witnesses and others, the agency says.
On the same day, Boeing responds to the FAA audit's conclusions announced the previous week.
"FAA inspectors went deep into our Renton factories in January and February to audit our production and quality control," says Stan Deal, the CEO of Boeing's commercial airplanes division.
The "vast majority" of problems, he adds, pertained to situations where Boeing employees didn't follow the company's processes and procedures. Deal promises to focus on improving compliance by working with employees and conducting more internal audits. Of the expert review, he says Boeing's procedures were too complicated.
"If you spot an issue, you are fully empowered to report it through your manager or the Speak Up portal," Deal says.