In a concerning development for the aviation industry, United Airlines (UAL.O) has reported the discovery of loose bolts on multiple 737 MAX 9 aircraft, prompting heightened scrutiny on the Boeing model already grounded after a recent mid-flight incident.

The revelation comes in the aftermath of a panel detachment on an Alaska Airlines-operated (ALK.N) plane over the weekend. United Airlines, conducting inspections in the wake of the incident, identified discrepant bolts on various parts of at least five panels, as reported by industry publication Air Current.

While United Airlines is actively addressing the issue, both the U.S. Federal Aviation Administration (FAA) and Boeing have refrained from providing official comments on the matter. The incident has raised concerns about the overall safety and maintenance of the 737 MAX 9 fleet, which has faced significant scrutiny since its initial grounding.