FRAMINGHAM (03/22/2000) - A cut cluster of cables left thousands of airline passengers across the country stranded yesterday and Northwest Airlines Inc. officials wondering why their backup system was also disabled.

The problem began at 2 p.m. CDT, when a subcontractor laying new lines bored through clusters of cables, cutting 244 fiber-optic and copper telecommunications lines. The lines included ones that link Northwest's Minneapolis-St. Paul hub to the rest of the nation.

What Northwestern officials soon discovered was that their redundant system lines apparently run alongside the lines they are backing up.

"What we don't understand is why the redundant system was also affected," said Kathy Peach, a spokeswoman for Northwest. "It does seem odd that the redundancy is so near the main lines. Because the cut was so severe, it also affected the redundant lines."

A spokesman for Denver-based US West Inc., the local phone provider whose lines were cut, did not return phone calls immediately. But a worker who did not want to be named blamed the problem on the "reckless abandon" of the subcontractor who was laying new cables for a US West competitor when the lines were cut.

According to Peach, Northwest had to cancel 130 of its 1,700 daily flights because of the problem, which disabled the airline's system for 3 1/2 hours.

The cut cables also knocked out some local phone service.