Air traffic controllers who guide planes in and out of Newark Liberty International Airport lost radar and communication with aircraft before dawn on Friday in another 90-second outage, the Federal Aviation Administration said, hours after the Trump administration unveiled a plan to overhaul the aging technology that keeps U.S. airspace space safe.

The outage occurred at about 3:55 a.m. ET, the FAA said. There are far fewer aircraft flying overnight, so disruptions were minimal compared with a similar outage on the afternoon of April 28, which snarled air travel for days.

Several controllers took leave because of the stress of that April incident, the FAA said. That exacerbated low staffing levels at the Philadelphia facility tasked with guiding planes in and out of Newark Liberty International Airport in New Jersey, forcing the FAA to slow the airport’s traffic.

Like in the April incident, Friday’s outage left controllers unable to communicate with aircraft and their radar screens dark.

Airlines and labor groups said in February that the U.S. urgently needs billions of dollars in emergency funding from Congress for improvements to air traffic control, which has faced both staffing shortfalls and outdated equipment.