The FAA is telling airlines to inspect and if necessary fix engines on popular Boeing 737 jets after four reports of engines shutting down during flights.
The Federal Aviation Administration order affects about 2,000 twin-engine passenger jets in the United States.
The 737 is one of the most popular aircraft in service around the world.
"Corrosion of these valves on both engines could result in a dual-engine power loss without the ability to restart. This condition, if not addressed, could result in compressor stalls and dual-engine power loss without the ability to restart, which could result in a forced off-airport landing," the agency said in a statement.
The FAA says operators must inspect any 737 that has been parked for at least seven days because of reports that engine valves can become stuck in the open position.
Passenger jets have two or more engines, and multiple engine failures are rare. But it has happened, including the 2009 "Miracle on the Hudson."