OUCH: Delta CEO lashes out at CrowdStrike: This cost us $500 million and they offered us nothing.

“If you’re going to have priority access to the Delta ecosystem in terms of technology, you’ve got to test this stuff,” Bastian said. “You can’t come into a mission critical 24/7 operation and tell us we have a bug. It doesn’t work.”

The computer problems at Delta knocked its crucial crew tracking system off line for the better part of a week, making it impossible for the company to find pilots and flight attendants it needed to fly its aircraft. While other airlines were quick to resume normal operations after the CrowdStrike outage, Delta was forced to cancel about 30% of its schedule over five days, leaving an estimated half-million passengers stranded. It took many days after that to re-book affected passengers on other flights and return their checked bags.

Delta has yet to file a lawsuit against either CrowdStrike or Microsoft, but a person familiar with its actions confirmed to CNN on Tuesday that it had hired the law firm of high-profile attorney David Boies to pursue compensation from the two companies.

Outsourcing critical support or manufacturing can be cheaper or provide expertise you don’t have in-house. But when things go wrong…