The US Federal Aviation Administration has made some changes to prevent outages similar to the one that disrupted thousands of flights earlier this month, according to reports from Reuters and Bloomberg. In a letter to lawmakers viewed by the outlets, FAA administrator Billy Nolen says the agency’s system now has safeguards in place to stop corrupt files from interfering with its backup database.

The outage took place on January 11th and involved a computer glitch affecting the FAA’s Notice to Air Missions (NOTAM) system. This system provides pilots and other personnel with essential status updates, including information about runway closures, flocks of birds in the airspace, and other safety hazards. The outage lasted more than two hours and impacted over 11,000 flights across the country.

Last week, the FAA attributed the glitch to contractors who “unintentionally deleted files while working to correct synchronization between the live primary database and a backup database.” However, as reported by Reuters, Nolen’s letter to lawmakers expands on this a bit and states that the FAA’s attempts to restore the deleted files also played a part in the outage.

To help prevent repeat incidents, Reuters says the FAA has implemented a one-hour delay in the time it takes for its databases to synchronize, which is supposed to block any erroneous changes from instantly taking effect in the backup database. The agency also “now requires at least two individuals to be present during the maintenance of the NOTAM system, including one federal manager.”

Several airline executives called on the US government to increase funding to the FAA following the outage. Delta CEO Ed Bastian said in an interview with CNBC that the incident wasn’t the FAA’s fault and instead blames it on a lack of resources and funding. “Hopefully this will be the call to our political leaders in Washington that we need to do better,” he added.

The current NOTAM system is made up of two conjoined parts: the 30-year-old legacy US NOTAM system and the Federal NOTAM System (FNS) that the FAA’s in the process of updating, according to Reuters. The FAA started modernizing the NOTAM system in 2019, and it expects to discontinue the legacy system by mid-2025, with the second phase of the upgrade slated for completion in 2030.

Last week, the House of Representatives passed a bill that would establish a team dedicated to studying the FAA’s NOTAM system, but it still needs approval from the Senate. Congress and the Department of Transportation are also looking into the mass flight cancellations at Southwest Airlines that occurred last month, leaving thousands of passengers stranded across the country.