@IanW;- The fire theory isn't 'baseless'. It's based on a known, T7-specific issue. Everything about this incident is unprecedented, but this is one area where at least one of the theories is grounded in
some known facts. Added to this, a current T7 driver has explained how he can see a chain of events that fit few facts known thus far. No Martians required.
Could there have been some mischief on-board? Of course, but for all the well-rehearsed reason chewed-over ad nauseam already on here, it doesn't seem likely. a/c have disappeared because of technical issues before. They haven't, as far as I'm aware, disappeared because a terrorist wanted to 'hide' a crash. They generally like to go out with a bang.
@RifRaf3;- No, it's not my 'Pet theory', nor even my theory. I'm just pointing out that it has some basis in reality, rather than just being based on nothing more than speculation....
As Egypt Air 990 perhaps?
The point I was making is the same as yours that there is no evidence of what happened until the DFDR and possibly CVR are recovered. There
are pointers such as the long flight - which would appear to obviate severe fire; the repeated changes in direction that happen to increase sea transit rather than a visual recovery to home base which would appear to indicate some kind of controlled flight to those waypoints a single incorrectly entered waypoint of course, multiple incorrect entries into an FMS when all the other electrics have failed and the aircraft is VFR on fire?