A computer systems failure at British Airways last month that left tens of thousands of passengers stranded was caused by two human errors from a contractor, the CEO of the carrier’s parent company said Monday.

“It wasn’t a computer meltdown,” Willie Walsh, CEO of International Airlines Group, said Monday during a media briefing at IATA’s annual general meeting in Cancun. “It was not a failure of IT.”

Walsh blamed the press for early reporting, saying media got it wrong by comparing the British Airways outage to other incidents when airline computer systems failed. But when the problem occurred, British Airways said little about what caused it, blaming it mostly on a power surge. It said backup systems were also not working, forcing it to cancel all flights from London’s Heathrow and Gatwick airports.

On Monday, Walsh said the outage was caused by an electrical engineer, who disconnected the uninterruptible power supply to the airline’s data center.

Ordinarily, Walsh said, such a mistake could have been corrected in a couple of hours, and the airline likely would not have canceled flights. But in this case, the problem was compounded when the power supply was reconnected.

“What caused the damage was that the power was restored in an uncontrolled fashion,” Walsh said. He said it caused “physical damage” to servers, power units and distribution panels.

Walsh said the airline might take legal action against the contractor. He did not name the company the engineer works for, but UK reports have said the engineer was employed by CBRE Global Workplace Solutions.

Walsh said he understood how a mistake might be made in turning off the power supply. But he said he was more surprised by the damage that was caused when it was turned back on.

“I think it’s fair to say that one of the reasons we didn’t disclose everything was because we wanted to be sure about the facts and to preserve our position,” he said. “We need to understand it better and then we’ll evaluate what our options are.”

As for the airline’s brand, Walsh said it had taken a hit, but will recover.

“We apologize to all of our customers who have been affected by this,” he said. “We will work to recover our position. British Airways is incredibility resilient. It’s a powerful brand. I’m not going to deny that this is something that has been damaging to the brand, but it hasn’t destroyed it in any way.”

Photo Credit: A computer systems failure at British Airways in late May was caused by human error, the CEO of the airline's parent company said Monday. British Airways