Airlines will likely suffer more disruptions like the one that grounded about 2,000 Delta flights last week because major carriers have not invested enough to overhaul reservations systems based on technology dating to the 1960s, airline industry and technology experts told Reuters.
Airlines have spent heavily to introduce new features such as automated check-in kiosks, real-time luggage tracking and slick mobile apps. But they have avoided the steep cost of rebuilding their reservations systems from the ground up, former airline executives said.
Scott Nason, former chief information officer at American Airlines Group Inc, said long-term investments in computer technology were a tough sell when he worked there.
"Most airlines were on the verge of going out of business for many years, so investment of any kind had to have short pay-back periods," said Nason, who left American in 2009 and is now an independent consultant.
The reservations systems of the biggest carriers mostly run on a specialised IBM operating system known as Transaction Processing Facility, or TPF. It was designed in the 1960s to process large numbers of transactions quickly and is still updated by IBM, which did a major rewrite of the operating system about a decade ago.
A host of special features, ranging from mobile check-ins to seat selection and cabin upgrades, are built on top of the TPF core, or connected to it.
"They have surrounded that old industry infrastructure with modern technology," said Bob Edwards, United Continental Holdings Inc's former chief information officer until 2014. "Those systems have to always reach back into the old core technologies to retrieve a reservation or to figure out who flies between Dallas and New York City."
When a power outage shuts off that reservations system - as happened on Monday to Delta Air Lines Inc's "Deltamatic" system - TPF falls out of sync with the newer technologies that passenger service agents use to assist travellers, Edwards said.
Airlines are then forced to cancel flights as demands from stranded customers flood their employees - who meanwhile are handling bookings on an older platform without their familiar, modern tools, he said.
Several years ago, it took United six hours to recover from a test shutdown, thanks to complications with the many add-ons built atop TPF, Edwards said.
Other recent disruptions include one in July that prompted Southwest Airlines Co to cancel over 2,000 flights and two outages last summer at United Continental.
PRESSURE FOR PROFITS
Delta spokeswoman Kate Modolo said in a statement that a small fire on Monday resulted in a "massive failure" at the airline's technology center. Delta was forced to cancel flights because critical systems did not switch over to backup power as intended, she said.
Reuters sent Delta and other major carriers detailed questions on TPF infrastructure and their technology investments.
Modolo did not answer whether Delta relies on TPF, but said "the functionality of the IT programs we use" was not an issue. She had no comment on whether Delta had decreased or increased its spending on back-end technology over the past decade.
"We have a new CIO who has a go-forward plan to ensure Delta is on the cutting edge of customer service technology while strengthening our IT infrastructure so that it is reliable, redundant and nimble," she said in a statement.
Most big airlines, including the four largest in the United States - American, Delta, United and Southwest - rely on TPF in some form, industry experts said.
In response to questions from Reuters, those airlines did not answer whether their aging systems put them at risk of future disruptions, but all stressed that they are upgrading their technology and are focused on reliability. Southwest, for example, said it is in the process of replacing its reservations system.
Earlier this week, in a video statement, Delta Chief Executive Ed Bastian said: "Over the last three years, we have invested hundreds of millions of dollars on technology infrastructure upgrades and systems including backup systems to prevent what happened yesterday from occurring. I'm sorry that it happened."
US and Canadian airlines are projected to spend an average of 3 percent of their revenue on information technology this year - compared to 8 percent by commercial banks and 4 percent by healthcare firms, according to Computer Economics, a firm that tracks IT spending.