Delta Air Lines flights gradually resumed after an outage hit its computer systems, grounding planes and stranding passengers of one of the world’s largest carriers at airports around the globe.

Atlanta-based Delta, the second-largest US carrier by passenger traffic, said it had cancelled about 300 flights after a power outage that began around 2.30am in Atlanta.

The power interruption caused a “system-wide outage,” Delta said. At about 10.30am, it said about 800 of its nearly 6,000 scheduled flights had taken off.

Georgia Power said a piece of Delta equipment failed and caused the airline’s computer systems to lose power. The problem at Delta did not affect other Georgia Power customers, and there was no area-wide outage, utility spokesman John Kraft said.

Kraft said he did not know the type of equipment that failed or why it did.

Like many large airlines, Delta uses its proprietary computer system for its bookings and operations, and the fact that other airlines appeared unaffected by the outage also pointed to the company’s equipment, said independent industry analyst Robert Mann.

Critical computer systems have backups and are tested to ensure high reliability, he said. It was not clear why those systems had not worked to prevent Delta’s problems, he said.

A Delta spokeswoman declined to comment when asked about backup systems.

Delta’s flight information was not showing correctly on Delta’s website or on airport information boards, and this could also take time to resolve, the carrier said in the latest update.


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