Barr, the USC aviation safety professor, said serious efforts to correct safety problems in the airline industry tend to increase in direct proportion to the number of people killed, while too little action is often taken in response to incidents in which no one is killed.

It even has a name: blood priority.

"The more blood that is spilled, the more corrective action is taken. The less blood that is spilled, the less corrective action that's taken," Barr said.