Bolts were missing from the cabin wall of the Boeing that made an emergency landing

An Alaska Airlines Boeing 737 MAX 9 had to make an emergency landing in January because part of the cabin wall was torn out. US accident investigators have now presented an initial report. Accordingly, four important bolts were missing from the fuselage part.

According to US accident investigators, the torn-out fuselage part of an Alaska Airlines Boeing 737 MAX 9 was missing the necessary fasteners. The condition of the fragment and the adjacent fuselage elements indicate the absence of four bolts in a securing mechanism, the NTSB said in a preliminary report. The bolts are actually intended to ensure that the fuselage part cannot move upwards.

On January 5th, shortly after take-off, a part of the fuselage in row 26 of seats broke off in Alaska Airlines’ almost new 737 MAX 9 with more than 170 people on board. At this point, some configurations of the more seat type have a door. The affected variant of the 737 MAX 9 instead has a cover that closes the opening. No one was seriously injured in the incident – however, by a lucky coincidence, the two seats directly at the opening remained empty.

Loose parts also found on other machines

After the incident, the US Federal Aviation Administration (FAA) and other authorities ordered all 170 similar aircraft of the type to be grounded for investigations. Alaska and United Airlines also found loose fasteners in the area on other planes. It was not until the end of January that the FAA released the procedure for inspections, after which the aircraft were allowed to take off again. No aircraft of the affected model are in use by EU airlines.

After the incident, the FAA announced stricter controls at Boeing – and some airlines also want to send their own inspectors to the production lines. Boeing boss Dave Calhoun reiterated after the preliminary NTSB report that the company ultimately bears responsibility for the aircraft. Boeing also assured that quality oversight would be improved immediately. The FAA had prohibited Boeing from planning to expand 737 production – the company should first get the problems under control, according to the instructions.

The fuselage of the 737 models is built by the supplier Spirit Aerosystems and then passed on to Boeing for final assembly. According to the NTSB’s findings, the fuselage fragment was removed at Boeing for rework. A Boeing photo shows the assembled component without the bolts. According to investigators, the lack of damage to the bolt holders also suggests that they were also missing during the flight.