1.   A team of air-accident investigators has discovered that unused tracks on cockpit voice recorders can reveal when an aircraft is about to suffer a catastrophic structural failure.

2.   But the crash might still turn out to have been an accident, a catastrophic failure of the aircraft or even a midair collision with an undetected small plane.

3.   Discussing the current theories on how a catastrophic mechanical failure could have occurred, the investigators expressed strong doubts about all of them,

4.   Engineers are also expected to develop techniques for testing the system to determine how vulnerable it might be to a catastrophic failure.

5.   For the short term, at least, online activities are safe from catastrophic failure for much the same reason that they remain vunerable to hacker attacks.

6.   He said the three leading theories were a terrorist act, catastrophic technical failure, or, as American officials surmised, an errant military missile.

7.   Investigators have said the midair exposition that destroyed the plan could only have been caused by a bomb, a missile or a catastrophic mechanical failure.

8.   Investigators have said the midair explosion that destroyed the plan could only have been caused by a bomb, a missile or a catastrophic mechanical failure.

9.   Lloyd Kelley, an inspector with the Federal Aviation Administration, said preliminary analysis suggests the engine had a catastrophic failure.

10.   Most experts are increasingly confident that Europe is not likely to see catastrophic failures.