More than 400 Boeing 737 MAX planes in the U.S. are at risk over a manufacturing defect that can cause seats to come loose during emergencies, officials warned.

The Federal Aviation Administration warned that the seats on 453 Boeing aircraft may not have been installed correctly, urging operators to inspect the popular 737 model to ensure they are up to safety standards.

The agency warned that improperly installed seats could become loose during turbulence and potentially injure passengers or crew, hinder an emergency landing, obstruct the aisle or cause delays during an emergency evacuation of the aircraft.

The directive requires “a detailed inspection of the seat track fittings of each left and right side track-mounted passenger seat assembly for correct installation,” the FAA said.

While the FAA's authority extends only to U.S. airlines, foreign regulators typically adopt similar directives when applicable.

It was not immediately clear whether any Boeing 737 MAX — the company’s most widely flown model — in other parts of the world were impacted by the issue.

There are nearly 2,300 737 MAX aircraft currently in service across the globe, including 823 in the U.S., according to aviation intelligence firm IBA.

The directive comes as Boeing is working to improve its production quality after issues were revealed in 2024 when a door-plug panel blew out of an Alaska Air 737 MAX while in flight.

None of the 171 passengers or six crew members on the flight were seriously injured, and pilots were able to safely land the plane back at the airport it departed from in Portland, Oregon. The FAA fined Boeing $3.1 million for safety violations from September 2023 to February 2024, which included the incident.

The FAA said in the airworthiness directive proposal that it received a report that some passenger seat assemblies were not correctly installed in the seat tracks.

That meant the assemblies could disengage from the seat tracks if there was an increased load, turbulence or an emergency landing, the FAA said.

There could be up to 69 track-mounted passenger seat assemblies on each 737 MAX plane, and the issue would take an estimated one work hour to inspect and then an hour to fix each assembly and required no parts, the FAA said. Airlines might be able to have multiple employees inspecting seats simultaneously, greatly reducing the total time for each aircraft.

The FAA did not specify how long it would take airlines to correct the issue.

A Boeing spokesperson said it issued guidance to operators about the problem in December 2025.

"We support the FAA making that guidance mandatory," the spokesperson said in an email.