It’s been two years since a Spanair plane crashed just after take-off at an airport in Madrid. It was the worst crash the country had seen in 25 years, and killed 154 people.

The United States is involved in the investigation; it was a U.S.-built plane. And officials have already released many of the details of the crash. Part of the problem: The wing flaps and slats were not in the right position at take off. That’s kind of like driving a car with the doors open. Also at issue … malware.

We talked with Bill Waldock about how malware was involved. He’s a professor of safety science at Embry-Riddle Aeronautical University in Prescott, Ariz., and associate director of the university’s Center for Aerospace Safety Education. We also hear from Jeff Moss, founder and director of the Black Hat computer security conference, about the kind of malware found on the airline’s computer system and how it may have done the damage it did.