On the Unintended consequences of Arbitrary Limits

Software failure caused ComAir to cancel all flights just before Christmas, a move that inconvenienced thousands of travelers. Ars Technica reveals the cause was an arbitrary limit incorporated into ComAir's scheduling software:

At the core of the problem was an application created by SBS, a subsidiary of Boeing. What happened on SBS's system is that the massive ice and weather delays necessitated an abnormally high number of crew reassignments which overflowed a hard limit of 32,768 changes per month. The result being that the application either crashed, stopped working, or began acting irrationally. With this critical system out of play, no one knew where send people or where to get crewmembers for new and rescheduled flights. The application crash, on top of weather delays and a lack of glycol to de-ice the planes caused the cancellation of thousands of flights in and out of the Cincinnati airport only days before Christmas.

Ah, the joys of a software dependent world!