Renton Municipal Airport is seen from above. The enormous buildings at the edge of Lake Washington are Boeing's 737 Max wing fabrication and three final assembly lines. The factory today produces between 38 and 42 single-aisle airplane every month.
Investigation involving Alaska Airlines Flight 1282 on a Boeing 737-9 MAX in Portland, Oregon.

127 Days: The anatomy of a Boeing quality failure

Reconstructing Alaska Airlines' 737 Max 9 N704AL from final assembly to Flight 1282

Log-in here if you’re already a subscriber

Release Date
January 24, 2024
127 Days: The anatomy of a Boeing quality failure

Air safety reporting by The Air Current is provided without a subscription as a public service. Please subscribe to gain full access to our all scoops, in-depth reporting and analyses.

In late August, a cavalcade of 737 fuselages rolled into Renton, Washington after their journey by rail from Wichita, Kansas. Each of the green-coated structures was labeled with a number, designating the sequence in which it was built at Spirit AeroSystems. One in particular, with 8789 stenciled on its side, would wind its way through Boeing’s factory in late summer 2023 becoming the flashpoint for not just another occurrence in a series of acute safety crises for Boeing, but an explosive force for change within a company that has no equal in the U.S. economy and only one true peer globally.

The Air Current has meticulously pieced together the fabrication and the journey of airplane 8789 to become N704AL, the Boeing 737 Max 9 flown on Alaska Airlines flight 1282, which violently lost a plug exit at 14,830 feet over Oregon on Jan. 5. Many crucial facts are now known to TAC. When the fuselage 8789 arrived at Boeing’s factory, the plug exit had four key bolts installed, each designed to prevent movement of the plug and the type of blowout the NTSB suspects occurred aboard flight 1282.

What comes next is the reconstruction of a mystery, including a sequence of events that has been assembled through interviews with directly knowledgeable people, and confirmed by those briefed on the situation, detailing a compounding series of quality missteps that put the lives of 171 passengers and six crew at risk. There is also a paper trail that shows the plug exit was opened by Boeing late in the assembly process to fix nearby rivets in the fuselage that had been improperly installed by Spirit AeroSystems, which provides 70% of each 737 to Boeing.

Related: The fallout for Boeing will extend far beyond the 737 Max 9 grounding

The Air Current has closely reviewed one purported account of what went on in the factory, compiled by an alleged whistleblower as a buried comment on a Jan. 15 blog entry posted by Leeham News. TAC has not identified the whistleblower or the veracity of every claim made in that person’s extended narrative. However, TAC’s own independent reporting contained in this report confirms some aspects of that account and adds considerable new facts. Only those items that we have been able to independently confirm through our own reporting are included here.

By many accounts, when fuselage 8789 entered Boeing’s Renton plant, things were already not going well. Both Boeing and Spirit were grappling with issues on another Max sibling, the Max 8, which weeks before had been found to have hundreds of misdrilled holes in its aft pressure bulkheads — a story first reported by The Air Current. Unlike the later plug exit issue, which was an acute safety concern, the aft pressure bulkhead did not present the same immediate risk, though each and every one needed to be analyzed or reworked before they could be delivered to airlines.

Renton Municipal Airport is seen from above. The enormous buildings at the edge of Lake Washington are Boeing's 737 Max wing fabrication and three final assembly lines. The factory today produces between 38 and 42 single-aisle airplane every month.
Renton Municipal Airport is seen from above. The enormous buildings at the edge of Lake Washington are Boeing’s 737 Max wing fabrication and three final assembly lines. The factory today produces between 38 and 42 single-aisle airplane every month.

When 8789 went through its initial manufacturing inspections, Boeing staff on Aug. 31 discovered (and later fixed) loose fasteners on the right-hand side plug exit. It remains unclear how loose the parts were, but it was considered by Boeing to be a defect. On the opposite side of the aircraft, next to the left-hand plug that failed on Alaska 1282, Boeing made another quality discovery.

Rivets installed at Spirit in the fuselage structure just forward of the plug exit door frame weren’t installed properly in five locations and required rework. In documenting the defects, the quality control report observed four properly installed bolts were fitted to the exit plug, preventing its movement.

Subscribe to TAC

On Sept. 1, 8789, was sitting loaded in Boeing’s massive systems installation tool and later moved by crane to the middle of three final assembly lines in Renton — the one least disrupted by the aft pressure bulkhead inspections and rework happening on the 737 Max 8s in the factory. Spirit’s warranty obligations to its product meant that responsibility for fixing the rivets on 8789 would fall to Spirit and its staff working in Boeing’s factory. The fix was delegated that same day to Spirit staff who had had a presence — either in the form of direct staff or contractors to Spirit — in Boeing’s factories for years, as have representatives of other suppliers. 

It is here where the dysfunctional relationship between Boeing and Spirit manifests itself. The haggling over who is responsible for fixing issues that reach final assembly, and ultimately who pays to fix any issues, underscores the long-running strategic tension between the two companies. The delegation of those repairs, one knowledgeable person said, adds both time and needless complexity as Boeing factory staff wait for Spirit staff to plan and implement fixes, slowing down the entire process all under the same roof.

Related: Inside the strained union of Boeing and Spirit AeroSystems

Over the following week, while 8789 moved down the center line toward the massive hangar door that faces the southern shore of Lake Washington, Spirit had its hands full as the required fix to the rivets went into an extended queue of work for the supplier to resolve, right in the middle of the Labor Day weekend holiday.

On Sept. 7, the rivets in question were found to be painted over and the underlying issue with their improper installation not addressed. It is not clear at this point who specifically painted over the rivets, but Boeing quality control sent the fasteners back for rework to Spirit, which itself assigns the work to contractors for the company, not its own direct employees. 

That same day, Spirit’s then-CEO Tom Gentile and Boeing CFO Brian West attended a Jefferies Co. investor conference to explain to investors what was going on with the aft pressure bulkhead inspections and rework that had taken over factory operations at both companies.

“Let me just talk about quality in general,” said Gentile, who resigned later in the month and was replaced by Spirit board member, and former acting Secretary of Defense, Pat Shanahan. “We have a quality management system that actively and continuously seeks out quality issues so that we can fix them and make our products with better quality and safer in terms of outcome.”

Another five days would go by as the airplane progressed through final assembly. On Sept. 12, Boeing conducted a standard test on the aircraft to confirm its structural integrity and its ability to be safely pressurized. 8789 passed successfully, TAC is told. During this period the damaged rivets remained unfixed and an additional five days passed while a final resolution was being planned by Boeing and Spirit. 

The key moment, The Air Current has learned, came on Sept. 18 when the plug exit was opened by Boeing to give Spirit contracted staff access to fix the rivets. Whether the plug was removed or just opened remains unknown. TAC understands that only if it had been removed fully would it have required documentation cataloging this move, but not if cracked open in a standard maintenance mode. 

TAC also understands that a new door seal on the plug exit to ensure safe pressurization was also required as part of the fix. The significance of this is not fully known by TAC, but potentially relevant given the pressurization anomalies experienced by N704AL in service on Dec. 7, Jan. 3 and Jan. 4 — the day prior to the accident and ultimate loss of pressurization when the plug exit was expelled into the night’s sky.

Regardless, the four key bolts that hold the plug in place must be removed to either open or remove the 63-pound plug. The whereabouts of the bolts, according to the NTSB, remain central to understanding what caused the explosive decompression aboard Alaska 1282. 

The rivets were fixed fully the following day on Sept. 19. What happened next in the factory is not entirely clear, yet is just as essential to understanding the quality failures that led to the accident and Boeing CEO David Calhoun’s own direct admission of a “quality escape” that led to the accident aboard flight 1282 and triggered the Max 9 grounding.

Airplane 8789, now fully assembled, was seen outside the Renton factory on Oct. 8 and later moved to the flight line for its Oct. 15 maiden flight. The aircraft, still wearing the bare green coating applied by Spirit during manufacturing, returned to Renton for painting in Alaska’s company colors and formally adorned with N704AL. Flown again by Boeing on Oct. 22 and twice by Alaska production test pilots on Oct. 27 and 28 for the company’s acceptance flights, 8789 was formally delivered as N704AL on Halloween.

What followed next was a fairly routine set of procedures for Alaska. The aircraft was flown to Oakland International Airport where the company has a maintenance base and routinely inducts new aircraft to its fleet, as with the delivery of a Max 9 The Air Current was a part of just six weeks earlier. N704AL spent 11 days in California, and was ferried to Portland for its maiden revenue service on Nov. 11 to Orlando.

Just after Thanksgiving, N704AL was ferried to Oklahoma City for installation of its satellite internet wi-fi system. In the days following the accident, AAR, which is contracted to perform the installation on the aircraft, said in a statement that the company’s staff “did not perform any work on or near any mid-cabin exit door plug of that specific aircraft.” The aircraft returned to revenue service on Dec. 7 with a flight from Seattle to Ketchikan, Alaska.

NTSB Investigator-in-charge John Lovell inspects N704AL in Portland after Alaska Airlines flight 1282 earlier in January.
NTSB Investigator-in-charge John Lovell inspects N704AL in Portland after Alaska Airlines flight 1282 earlier in January.

The aircraft operated without significant incident until the afternoon of Jan. 5 when N704AL, operating as Alaska 1282, suffered its explosive decompression, kicking off this ongoing crisis.

A Boeing spokeswoman said, “​​As the air safety agency responsible for investigating this accident, only the U.S. National Transportation Safety Board can release information about the investigation. As a party to this investigation, Boeing is not able to comment and will refer you to the NTSB for any information.”

Spirit declined to comment on the specific elements of this story, saying it “is precluded from providing information regarding the ongoing investigation, to which it is an active party. As a company, we remain focused on the quality of each aircraft structure that leaves our facilities.”

The Federal Aviation Administration referred questions about the investigation to the NTSB, which declined to comment on this report.

Return to service and FAA ‘boots on the ground’

The FAA and Boeing on Jan. 24 — 19 days after the accident — approved the means of compliance that will now allow airlines to ultimately return their 737 Max 9s to service following detailed inspections. “We will continue to cooperate fully and transparently with the FAA and follow their direction as we take action to strengthen safety and quality at Boeing,” the plane maker said in a statement provided to TAC. “We will also work closely with our airline customers as they complete the required inspection procedures to safely return their 737-9 airplanes to service.”

Those customers — Alaska and United Airlines in the U.S. — appear to be raring to return the airplanes to their networks following weeks of delays and cancellations caused by the groundings. Alaska said that it plans to resume flying with its Max 9s on Friday, Jan. 26, and United a few days after on Jan. 28. The efforts, which require the removal of the plug exit, include inspection of “specific bolts, guide tracks and fittings,” according to the FAA. 

Related: Supply chain fragility drives fourth 737 Max line decision

The scrutiny by the FAA and NTSB on Boeing remains extreme. With the clearance to return to flying, the FAA also announced that it was halting Boeing’s proposed expansion of its 737 Max production lines in Everett, Washington, home to its west coast widebody assembly operations. That was supposed to start this summer and the FAA will force the planemaker to cap its output at between 38 and 42 per month — its current levels on its existing lines.

“Let me be clear: This won’t be back to business as usual for Boeing,” said FAA Administrator Mike Whitaker. “We will not agree to any request from Boeing for an expansion in production or approve additional production lines for the 737 Max until we are satisfied that the quality control issues uncovered during this process are resolved.”

Related: United CEO expresses support for Boeing, not necessarily its leadership

This comes in addition to previously-announced probes into the company’s quality control and manufacturing efforts, which now include planned investigative hearings in front of the Senate Commerce, Science & Transportation Committee. 

Whitaker said Wednesday that the agency had moved beyond its original audit of Boeing’s production system and toward specific focused teams inside its operations. “The quality assurance issues we have seen are unacceptable,” said Whitaker. “That is why we will have more boots on the ground closely scrutinizing and monitoring production and manufacturing activities.” 

Will Guisbond also contributed to this article.

Write to Jon Ostrower at

Zeen is a next generation WordPress theme. It’s powerful, beautifully designed and comes with everything you need to engage your visitors and increase conversions.