Boeing, safety officials haven’t identified who reinstalled 737 door plug incorrectly

Boeing (NYSE:BA) and aviation safety authorities haven’t been able to figure out who reinstalled a door plug on a new 737 Max-9 jet that was forced on January 5 to make an emergency landing, leading to another crisis for the plane maker.

“The safety culture needs a lot of work,” National Transportation Safety Board Chair Jennifer Homendy said about Boeing (BA). “It is not there from the evidence itself, from what you see in the interviews. There’s not a lot of trust, there’s a lot of distrust within the workforce.”

The NTSB on Tuesday began two days of hearings about the incident on Alaska Airlines flight 1282. Shortly after taking off from Portland International Airport in Oregon, the door plug blew out from the main body of the plane, depressurizing the cabin and terrifying passengers.

The agency determined that the door plug, which is used in place of an emergency exit on some configurations of the 737 Max-9, left Boeing’s (BA) factory missing four key bolts. Boeing (BA) previously said necessary documents about the door plug’s reinstallation at its factory weren’t created.

Workers removed the door plug to do another repair on the plane’s fuselage, or main body, that was damaged. Spirit AeroSystems (SPR) assembled the fuselage and shipped it by train to Boeing’s (BA) factory outside of Seattle.