More than 60 flights out of Denver International Airport this morning were affected by a Federal Aviation Administration computer system shutdown Tuesday night and Wednesday morning. 

Tuesday night, the FAA’s Notice to Air Missions system (NOTAMs), which provides safety info to flight crews, experienced an outage that resulted in delayed and cancelled flights across the U.S.

NOTAMs alert pilots of potential adverse flight impacts such as runway construction or potential weather hazards, and is necessary for pilots to fly safely.

Following the outage, the FAA ordered airlines to pause all domestic departures until 9 a.m. EST “to allow the agency to validate the integrity of flight and safety information.” 

The FAA said on Twitter that all flights currently in the sky were safe to land – takeoffs were not allowed.

A DIA spokesperson said the outage effected more than 60 flights out of the airport this morning. According to flight tracking site FlightAware, 67 flights were cancelled and 791 flights were delayed out of DIA as of 3 p.m. Wednesday. 

The Colorado Springs Municipal Airport officials reported 16 flight delays in-and-out of the airport Wednesday morning, according to airport officials. No cancellations are expected.

By 6:50 a.m., the FAA lifted the ground stop, however the delays will likely cause a ripple effect on flights for the rest of the day. 

“There may be a domino effect as we also expect many flights today will be delayed and some will be cancelled due to the ground stop,” the spokesperson said. “Passengers should check their flight status with their airline before heading to DEN.”

There is no evidence of a cyberattack at this point, but President Joe Biden directed the Department of Transportation to conduct an investigation into the cause of the outage, according to the Office of the Press Secretary on Twitter.

The NOTAM outage affected flights across the U.S. after it broke down late Tuesday, leading to more than 1,000 flight cancellations and more than 6,000 delayed flights by 11 a.m. Wednesday, according to FlightAware.

Gazette reporter Abbey Soukup and the Associated Press contributed to this story.