The failed computer system that caused flight delays across the USA has been restored, the Federal Aviation Administration said Thursday.

FAA spokesman Paul Takemoto said the system went out at 5:06 a.m. ET and came back on about five hours later. He said officials working to pinpoint the cause know that there was a problem with the main telecommunications systems.

According to the Federal Aviation Administration (FAA), a computer system in Atlanta, Georgia, which processes flight plans stopped working properly.

As a result, controllers were forced to enter flight plans manually.

The FAA said the safety of planes in the air was not affected and, according to US media reports, the computer system is now working again.

The system — the National Airspace Data Interchange Network, or NADIN — appears to be the same one that failed in August 2008. The FAA said the information in the network is data required to launch planes expeditiously. Airplane safety was not affected, the FAA said, adding that planes in the air had radar coverage and communication.