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

The Federal Aviation Administration said the radar at the facility in Philadelphia that directs planes in and out of Newark airport went black for 90 seconds at 3:55 a.m. Friday. That's similar to what happened on April 28.

That first radar outage led to hundreds of flights being canceled or delayed at the Newark airport in the past two weeks after the FAA slowed down traffic at the airport to ensure safety. Several controllers also went on trauma leave after that outage, worsening the existing shortage.

The FAA said earlier this week that it is installing new fiber optic data lines to carry the radar signal between its facilities in Philadelphia and New York. Officials said some of the lines connecting those two facilities are outdated copper wire.

Transportation Secretary Sean Duffy announced a multi-billion-dollar plan Thursday to replace the nation's aging air traffic control system to prevent problems like this from happening and give controllers modern technology.

Officials developed the plan to upgrade the system after a deadly midair crash in January between a passenger jet and an Army helicopter killed 67 people in the skies over Washington, D.C.

But the shortcomings of the air traffic control system have been known for decades. The National Transportation Safety Board has not determined that a problem with the air traffic control system caused that crash near Reagan National Airport.