11.   At the same time, though, the attention on the criminal investigation caused some friction with investigators from the safety board, who were focusing on mechancial explanations.

12.   Before the tapes were released, the safety board mailed a transcript to the families of crash victims.

13.   Boeing chief engineer of fuel systems Ivor Thomas reassured the safety board that Boeing is aggressively working on studies to make airspace in fuel tanks less volatile.

14.   Boeing has sent a team to Paris to examine the jet, as have the safety board and American Airlines.

15.   Boeing has said more or less the same as the safety board said Thursday, in even more pronounced engineering prose.

16.   Boeing is assisting the safety board in the investigation.

17.   Boeing still does not acknowledge that such a rudder movement occurred, and the safety board has not reached a conclusion.

18.   A contributing factor was an inappropriate transmission by the pilot of the third plane, the safety board said.

19.   A fundamental difference between the safety board and the FBI is that they have far different standards of evidence.

20.   A key issue for the safety board is whether federal regulations adequately represent the conditions that planes are likely to encounter in routine use.