Dec 29, 2004 (08:12 AM EST)
Comair Downed By Computer Counting Limit

Read the Original Article at InformationWeek

The computer failure that grounded an airline's entire fleet over the Christmas weekend and stranded thousands of travelers was due to creaky software that couldn't count higher than 32,768, according to a report in the Cincinnati Post.

Delta subsidiary Comair halted all operations Saturday Dec. 25 and grounded 1,100 flights after a computer crash of its flight crew scheduling software, said the Post. Comair, a regional airlines owned by Delta, is headquartered in Cincinnati.

According to the Post, the software -- which tracks all details of crew scheduling, including how long they have flown (an FAA regulation restricts airtime), and logs every change -- has a 16-bit counter that limits the number of changes to 32,768 in any given month.

"This probably seemed like plenty to the designers, but when the storms hit last week, they caused many, many crew reassignments, and the value was exceeded," a computer consultant from Los Angeles, Tom Carter, was quoted by the Post.

Minus the computer, Comair was forced to either schedule manually or toss in the towel. It tossed in the towel.

"You can't operate an airline without a crew scheduling system," Comair spokesperson Nick Miller told the Post.

On Wednesday, Comair said that it had returned to a normal operating schedule, but the airline faces an investigation by the federal Department of Transportation, which launched a probe into holiday flight problems on Monday.