Inspections of some older Boeing jets have turned up structural cracks in more than three dozen of them, raising a new safety issue for the company, which is already dealing with two deadly crashes involving a newer version of the same plane.

Boeing said Thursday that airlines worldwide have inspected 810 planes following an order from U.S. safety regulators, and 38 — or 5% — had “findings” that will require repairs.

Airlines are under orders to inspect certain Boeing 737 NG planes for cracking in a part that helps keep wings attached to the fuselage.

Boeing isn’t identifying which airlines found problems, but Brazil’s Gol grounded 11 planes and U.S.-based Southwest Airlines grounded two.

(AP)