Whenever there’s an issue in the nation’s airspace, like the current string of delays and cancellations at Newark Liberty International Airport, air traffic controllers come under a microscope.

The air traffic controllers directing planes into the Newark, New Jersey, airport lost their radar Friday morning for the second time in two weeks.

FAA officials confirmed that radar guiding Newark flights went dark again early Friday morning, raising fresh concerns over air traffic safety. Planes at New Jersey’s Newark Liberty International Airport were briefly left flying blind overnight as the airport experienced another radar outage—the second incident in less than two weeks.