The Federal Aviation Administration had already been close to ordering airlines using that particular engine, the CFM-56B, to conduct ultrasonic inspections. The agency appears to have been prompted to act after another Southwest 737 engine came apart in 2016, sending debris into the plane’s fuselage, wing and tail. The investigation into that incident is ongoing.

Late Wednesday, the F.A.A. said it was ordering those ultrasonic inspections. The engines on both Southwest planes, were manufactured by CFM International, a joint venture of General Electric and Safran of France.

The National Transportation Safety Board concluded that the inspections were insufficient to detect flaws in the disk of a CF-6 engine on an American Airlines Boeing 767 in late 2016. The plane was gaining speed on the runway in Chicago when the engine broke apart, sending metal fragments into the fuel tank and igniting a fire. The engine was manufactured by General Electric.

The chairman of the transportation safety board, Robert L. Sumwalt, said on Wednesday that the problems with the Southwest engine were worrisome because the agency had already discovered in the Chicago incident that some engine flaws were undetectable. “We are concerned about it,” Mr. Sumwalt said.

Inspections have also been ordered for the Rolls-Royce Trent 1000 engines that power a quarter of Boeing’s newest wide-body, the 787 Dreamliner, after cracks were found on rotor blades. But the F.A.A. went further and rescinded the operators’ approval to fly the airplanes any farther than 2 hours and 20 minutes from an emergency airport.

International long-haul carriers like United Airlines, Qantas Airways, Japan Airlines, Air New Zealand and British Airways purchased the Dreamliner over the past decade specifically for the plane’s ability to carry fewer people on longer routes more fuel efficiently. On extended flights over water, an airline could schedule flights on routes of up to five hours flying time from an emergency airport.