11.   One of the issues discussed, according to one participant, were steps being considered for other airplanes to prevent similar crashes.

12.   Some fatal air crashes could be prevented by using nothing more sophisticated than a wire attached to a tape recorder.

13.   Such a system could prevent crashes.

14.   The devices give pilots more time to evade obstacles and prevent crashes.

15.   The equipment would not have prevented the crash, the report said, but should have been functioning.

16.   The National Transportation Safety Board concluded that a ground-traffic system due to be in operation would have prevented the crash.

17.   The National Transportation Safety Board and railroad unions say rail alignment sensors could prevent such crashes.

18.   Though these devices do not prevent plane crashes, they are invaluable for investigating them.

19.   Until recently, computer scientists have been stymied over the problem of figuring out the best way to prevent crashes on the Web.

20.   An electronic device designed to prevent such crashes failed to function, and police opened an investigation into the reason for the crash.