Takata,
you made the point that abscence of ACARS messages regarding the engines could indicate both engines died off simultanously. After that, ACARS would be inoperable, so the message reporting the engine failure could never be sent.
How simultanously do the engines have to fail, for no ACARS to be sent ? I would think, if they do not fail within 3 s at least the attempt for reporting the failure of the first engine should show up in the logs of the satellite operator ? Do you know of any precedent for the A330 in which both engines died off within such a short timespan ?