The air traffic controllers directing planes into the Newark, New Jersey, airport briefly lost their radar Friday morning for the second time in two weeks, renewing concerns about the nation's aging air traffic control system that President Donald Trump wants to overhaul.

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. Five controllers also went on trauma leave after that outage, worsening the existing shortage. It’s not clear if any additional controllers will go on leave now.

The number of cancellations and delays spiked after the FAA limited traffic at Newark and has remained high since then. The FAA plans to talk with all the airlines that fly out of Newark about cutting their schedules while the staffing and technology issues persist.

The number of cancellations Friday morning was down around 40 departures and arrivals, but increased after the radar outage and a disruption related to ongoing runway construction. By the end of the day 68 departures and arrivals had been canceled in Newark, and more than 400 delays were reported.

White House Press Secretary Karoline Leavitt said in a briefing Friday that the “glitch this morning at Newark” was caused by the same issues as last week.

The latest Newark problems reinforce the need for the multi-billion-dollar plan Transportation Secretary Sean Duffy announced Thursday to replace the nation’s aging air traffic control system, Leavitt said. The plan is designed to prevent such problems from happening and give controllers modern technology. More than 4,600 new high-speed connections would be installed and 618 radars would be replaced across the country.

Officials developed the plan to upgrade the system after a deadly midair collision in January between a passenger jet and an Army helicopter killed 67 people in the skies over Washington, D.C. Several other crashes this year also put pressure on officials to act.

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.

These radar outages in such a crowded airspace are alarming because seconds matter, but Allied Pilots Association spokesman Capt. Dennis Tajer said “it’s not an impending disaster that some are suggesting.”

“The system is wired to run really well when everything’s functioning. But the most important part is that it’s prepared to function when things go wrong,” Tajer said. “Even when it sounds frightening, know that the air traffic controllers and the pilots have training and we go to that.”

When pilots lose contact with controllers their first action is to continue on their last-directed path, but if the outage continues, pilots will start broadcasting their position to every other plane in the area — much like pilots do at small airports that don’t have a control tower.

U.S. Rep. Josh Gottheimer blamed the problems that have plagued Newark on the lack of proper air traffic controller staffing and modern technology. He said at a news conference Friday that there are currently about 20 controllers working, and that number should be in the 60s. And many of the lines connecting controllers to the radar are outdated copper wires. He said the April 28 outage was caused by one of those copper wires getting fried.

“Our region is a key economic artery for our country. Yet this region... one of the busiest air spaces in the world, as I mentioned, is running off a tower that’s full of copper wire dating back to the 1980s with outdated and inefficient technology. And the region is short — and this is a big deal. The region is short about 40 air traffic controllers,” Gottheimer said. He said the tower was built back in “the Brady Bunch era” in 1973.

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 that will be replaced. But it's not clear how quickly those repairs can be completed.

U.S. Sen. Chuck Schumer of New York said it's important that the FAA get the problems affecting the Newark airport fixed quickly.

“Enough is enough. The connection between New York air space and the Philadelphia air traffic control center must be fixed now. The backup system that is not working must be fixed. Now," Schumer said. "This is an air travel safety emergency that requires immediate and decisive action, not a promise of a big, beautiful unfunded overhaul that will take years to begin to implement.”