91.   Human errors in the design, however, can lead to cracks in any security system.

92.   Human error was largely to blame, including failure by security personnel to activate machines that detect explosives.

93.   In April, it announced a plan to reduce so-called runway incursions that included studying ways to reduce human error and improve ground communications.

94.   In modern subway systems, computers can control trains or override human errors.

95.   In half those cases, the problem was human error, Houghton said.

96.   In those realms, a finding of human error is likely to be the start of an investigation, not its conclusion.

97.   Investigators also thought it possible that equipment failure or human error caused the plane to crash as the pilot was trying to abort a landing in a driving rainstorm.

98.   Investigators say they believe that the crash was caused by an unusual combination of mechanical failure and human error.

99.   Investigators have not determined a cause or whether human error was a factor, he said.

100.   Investigators said their search so far indicates human error as the most likely cause of the accident.