The US Federal Aviation Administration has issued an emergency safety mandate to check fuel pumps on more than 560 Boeing 737 airliners flown by US carriers, the agency confirmed on Wednesday.

The inspections, required for four versions of the single-aisle 737, are meant to ensure that the fuel pumps turn off correctly. Failure to do that could result in fire or explosions, the FAA said.

Aircraft are not expected to be grounded for the checks, an FAA representative said, meaning that flights should not be disrupted.