It's not totally clear what's behind the computer failure that's plagued Delta Airlines since 2:30 AM on Monday morning. Delta calls it a power outage, while Georgia Power, the utility at Delta's Atlanta hub, calls it an internal computer glitch. The question is, why wasn't there backup behind the malfunction?
"The complexity of the system is a crucial factor in its failure," said Ahmed Abdelghany, who studies aviation IT systems at Embry-Riddle Aeronautical University in an interview with Wired. Airline computer systems often function via multiple layers, with data coming from diverse and often aging sources that are might be too expensive to update.
It looks as though in this particular scenario, the power outage specifically affected crucial computers or servers, Wired reported, which is why a second nearby command center and power supply weren't able to help.
Georgia Power, which provides electricity to Delta, has said they're now working together to fix the hardware—a failed switchgear, or large circuit breaker panel.
Thousands of passengers are now stranded and over 600 flights canceled or delayed due to whatever this global glitch may be. Delta has told passengers whose flights have been cancelled or significantly delayed that they're entitled to refunds. The airline has also agreed to give out $200 vouchers to disgruntled customers who have experienced a cancellation or delay longer than three hours.
Despite Delta's accommodations, experts say this shouldn't have happened to begin with. "Anytime you have a system wide outage, it either has to be one of the core systems or some sort of networking glitch," Rick Seaney, creator of travel website FareCompare.com, told the Washington Post. "All computer systems have redundancy. Typically, almost all companies—especially if you have credit card data—are required to be spread out, sometimes across different countries, to make sure that basically [their network] never goes down."
And if power goes out, they should have gasoline powered backups for at least 24 hours, he added. "Typically, what you have is two or three hours of battery backup and another 24 to 48 hours of gasoline-powered backup."
In the past 24 hours Delta has been dutifully updating its Twitter account and actively responding to customers. Still, customers are not happy. Many have taken to Twitter to express their qualms.
Delta's bad luck these past few days isn't an isolated event. Just last month, Southwest had to cancel 17 flights and delayed over 600 also because of a computer glitch. The same thing happened to JetBlue in May, and again to Southwest in October 2015.
For now as Delta works to get back on track, customers will likely continue to be upset. Experts say it will take several days for Delta to resume a normal schedule and return to the status quo. There's a limit on how long pilots and airline crews can be on duty, Jim Record, retired airline pilot and professor of aviation, said.
"The clock kept going for crews, even if they weren't on the planes…There aren't a lot of crews to bring in to replace them. That's not how the system is designed."