Last year, work inside Renton, Wash., factory stalled on a future 737 MAX jet then known as Line No. 8789. Pressure was building.

More than two weeks had passed since workers on Sept. 1 flagged damaged rivets on a fuselage that needed fixing. The section had been assembled by supplier AeroSystems in Wichita, Kan., and shipped by train to Boeing’s plant.

Targets for completion came and went before employees escalated the situation to “Tier 3” priority, a move intended to get high-level attention at the factory, according to an internal Boeing log of employees’ push to finish the jet—the same one that would later lose its door plug panel in a near tragedy in flight just months later.

Punctuating how the situation was escalating with dollar signs, an internal message read: “$$TIER-CHG: 2 – 3 $$,” according to a Sept. 17 entry in the Shipside Action Tracker, or SAT, reviewed by The Wall Street Journal. The SAT is like a factory Slack channel for fixing a production problem.

The communications of the Boeing employees working on the door plug, previously unreported, help illuminate why it blew off during an Alaska Airlines flight on Jan 5. The factory was in disarray. Crews were unable to keep a schedule and apparently didn’t follow procedures, and production pressure mounted as delays piled up, according to entries in the SAT, people who have reviewed the logs and interviews with Boeing employees who worked on the plane.

In their logs, workers extended 50 times the estimated time for completing work on the damaged rivets around the frame of the door plug. The delays ranged from a half-hour to days. The work was finally signed off on and officially completed by the morning shift on Sept. 20, after a final quality check was requested the previous day, the records show.

The production breakdown had stunning consequences: The jet’s door plug blew off in flight, triggering an explosive loss of cabin pressure that risked the lives of passengers who could have been sucked out midair. It has sparked federal probes, including a criminal investigation, and hastened the exit of senior leaders including Chief Executive David Calhoun, who had vowed to improve Boeing’s safety and quality.

A Boeing spokesman said the company is prohibited by federal rules from discussing the investigation and referred to recent remarks by executives that they will slow down the factories to focus on quality and will take new steps to prevent problems from being pushed down assembly lines. The company is in talks with Spirit to acquire the company in an effort to rein in the supplier’s quality issues and also recently changed its bonus plan for 100,000 workers to emphasize quality and safety over meeting financial targets.

“For years, we prioritized the movement of the airplane through the factory over getting it done right,” Brian West, Boeing’s finance chief, said at a recent investor conference. “That’s got to change. The leadership team got it in the immediate aftermath of January 5.”

The SAT logs show that a fix for the damaged rivets was in the works for days, and that workers had to wade through layers of management to get the problem addressed. That task required opening or removing the door plug, which was installed in place of an unused emergency exit.

The workers discussed what documentation was required if they opened or removed the plug. “If removal needed, a removal needs to be written first,” one staffer wrote on Sept. 17. Altering airplane parts requires documentation in the heavily regulated and safety-focused world of aerospace manufacturing.

No such documentation appears to exist, however, Boeing has told U.S. lawmakers and accident investigators who have since been probing why the door plug blew off. The National Transportation Safety Board has said workers appear to have failed to replace four critical bolts needed to keep the panel in place.

The SAT records show a manager communicated that a mechanic was opening the door plug, however.

The NTSB has said investigators haven’t been able to interview the manager who oversees the team of Renton employees responsible for door work. The safety board has said the manager is out on medical leave.
Starts and stops

When Calhoun, a Boeing director and former GE executive, took over as Boeing’s CEO in January 2020, he promised change by improving safety and engineering. “It’s going to last for a long time, and it’s going to be healthy,” he told reporters at the time. Two 737 MAX jets had crashed, taking 346 lives and grounding hundreds of Boeing planes for 20 months.

Then the pandemic grounded flights and halted factories at Boeing, rival Airbus and suppliers such as Spirit. By 2022, they were straining to meet a surge in demand for new jets as travel boomed. Boeing hired thousands of new staff and steadily increased 737 MAX production, and Calhoun issued financial targets that relied on plans for higher output.

Last year, the factories were still running with stops and starts as the company worked to return to production levels seen before the MAX crashes. Boeing delivered 580 737s in 2018, the year of the first crash.