The Federal Aviation Administration is ordering airlines that fly some Boeing 737 NG jets to inspect them for "structural cracks," the agency said Wednesday.
The order comes after cracks were discovered on some aircraft in China and further inspections found other cracks, the FAA said. The order does not affect the Boeing 737 Max, the troubled variant of the 737 that has been grounded since mid-March after two fatal crashes killed 346 people.
The inspections will be for a part known as pickle forks, which connect the wings to the aircraft's fuselage.
The FAA said the order will affect 1,911 aircraft in the U.S. and 165 of those will have to be conducted within a week. The inspections are expected to take about an hour for each plane.