51.   But even those who can afford to spend big bucks and leave the driving directions to satellites and electronic maps, human error still creeps in.

52.   But human error and arrogance also cost lives.

53.   But from the fragmentary and conflicting accounts now available, the accident appears largely due to human error.

54.   But now, purveyors of a new type of software, called supply chain management, say they can eliminate such human error once and for all.

55.   But it was unclear Wednesday night whether the disruption was caused by faulty software or human error.

56.   But that human in the booth also represents the only chance to correct human error.

57.   But the Board of Education said the leak did not result from a failure of the furnace, but rather was caused by human error.

58.   But several other facts point to human error that led to the very high toll.

59.   But they said the outlook could change, depending on whether the crash was the result of a mechanical or structural failure, or human error in operating it.

60.   But this year has been anything but typical, largely because of prolonged drought and persistent heat and, in some cases, arson or human error.