Radar screens at Newark Liberty International Airport briefly went dark early Friday in a telecommunications outage, the Federal Aviation Administration said.

The disruption occurred at 3:55 a.m. and lasted about 90 seconds, according to the FAA.

“There was a telecommunications outage that impacted communications and radar display at Philadelphia TRACON Area C, which guides aircraft in and out of Newark Liberty International Airport airspace,” the agency said in a statement.

Air traffic controllers who manage Newark’s airspace operate from a facility in Philadelphia, which is also short-staffed amid a nationwide controller shortage.

Friday’s outage follows similar issues last week, when controllers lost contact with airborne planes for at least 30 seconds. That failure led to widespread delays, cancellations and diversions.

In a letter to customers last weekend, United Airlines CEO Scott Kirby said the technology used to manage flights at Newark failed multiple times. He added that the situation worsened when more than one-fifth of the airport’s traffic controllers “walked off the job.”

United has since announced it will cut 35 flights from its daily schedule at Newark.

Meanwhile, U.S. Transportation Secretary Sean Duffy on Thursday outlined a plan to overhaul the nation’s air traffic control system, parts of which rely on components more than 50 years old. Duffy said some towers will need to be completely rebuilt, while much of the effort will focus on replacing outdated radar and communication systems.

That includes switching from copper wire to fiber optic cables, which was identified as the cause of last week’s Newark failure.

Duffy said he would be leaving the cost up to Congress but said it will likely be more than $12.5 billion.