United Airlines Computer Snafu Being Investigated

United Airlines, Cendant Corp., and IBM are jointly investigating the root cause of a computer malfunction that knocked out United's reservations and passenger-processing system for about 4 hours Tuesday evening, delaying 150 flights and preventing the airline from selling tickets during the outage. No flights were canceled.

According to United and Cendant, a processor failure crippled United's Apollo system at about 6 p.m. ET, forcing airline employees to switch to backup manual processes, including writing luggage tags out by hands. The resulting slowdown in checking baggage and issuing boarding passes caused hour-long delays, on average, across United's 170-plus-airport system. The 150 flights that were affected represented less than 5% of the airline's 3,400 daily flights. Most of the delays were centered on the East Coast as the outage came in the afternoon lull on the West Coast, and during the pre-dawn hours in Europe. "The timing certainly could have been worse," said a United spokesman.

Apollo is a Cendant-sold system that IBM manages out of a Cendant Travel Distribution Services data center in Denver. It was initially developed in the early 1970s by United, and was subsequently spun off into an independent reservations and distribution system operation. It was later combined with the Galileo Co. Ltd.; a distribution company formed by several European airlines, changed its name to Galileo International, and was acquired by Cendant in 2001 for $2.9 billion. United is the only airline that uses Apollo as its reservations system today.

A Cendant spokeswoman said repairs to the system were completed at 10 p.m. ET Tuesday, but could not provide any more details. "We're not going to want to speculate on what caused this."

Meanwhile, the United spokesman acknowledged that the airline's customers could not buy tickets during the outage, but he was uncertain what the financial impact on the airline would be.