One of the region’s busiest ports has come under scrutiny since revelations that its tower has lost contact with several airlines in recent months. Radar screens at Newark Liberty International Airport went black early Friday morning, raising more air traffic safety concerns at one of the region’s busiest hubs, federal authorities said. Air traffic controllers could be heard telling a FedEx plane that their screens went dark and then asking the aircraft to tell their company to put pressure on to get the problem fixed.

In another transmission, a controller told an arriving private jet that the airport just had a brief radar outage and to stay at or above 3,000 feet in case the controllers couldn’t get in touch during the aircraft’s descent.

MORE: Plans for new air traffic control system unveiled by transportation secretary
The FAA called it a “telecommunications outage that impacted communications and radar display at Philadelphia TRACON Area C,” which is the facility that covers the airspace around Newark.

Last week, an outage at Newark caused ATC computer screens to go dark for roughly 60 to 90 seconds and prevented controllers from talking to aircraft during that time, according to multiple sources with knowledge of the incident. As a result, the FAA briefly halted all departures to the airport.

Following the outage, several controllers went on medical leave, calling the experience a traumatic event. The controllers are entitled to at least 45 days away from the job and must be evaluated by a doctor before they can return to work.