21.   Linda Shaughnessy, assistant air traffic manager at Fort Worth Center, said that when the failures occur the system shifts to a backup.

22.   Meteorologists suffered partial blindness on Tuesday when a system failure occurred on the geostationary satellite that covers eastern North America, South America and the western Atlantic.

23.   Moreover, the office found that the study did not prove that power failures had really occurred for unavoidable physical reasons.

24.   Most Firestone failures have occurred in hotter climates and in states where the roads are more wide open and the distances routinely traveled greater than in New England.

25.   Most people assume that the worst power failures occur in the late summer when violent thunderstorms and hurricanes assault the power lines with savage winds and harsh rain storms.

26.   Officials said they did not know why the power failure had occurred.

27.   Other failures may occur due to the way the fence was built.

28.   Other operational failures occurred.

29.   Owners are urged to replace the buckles before a failure occurs.

30.   Pump failures also occur, said Dr. Eric Rose, chairman of the department of surgery at Columbia University.