There was no FCU malfunction, the overrun occured because the crew didn't know that at the end of the VNAV descent, which coincided roghly with the MAP, the autothrottle would have commanded go around thrust (incredibly, during the investigation, they found out all other AF 744 pilots didn't know as well this behaviour).
The copilot, when he felt the thrust levers advancing, instead of disconnecting pulled them back and hold them back (!), yes, all except N°1 (small hand maybe...).
At touchdown of course there was no spoiler nor autobrake, nor the captain was aware of what was going on.
Despite heavy braking, eng 1 was still producing full thrust when they skid to the right in the lagoon...
Firefighters eventually shut the engine down with water...
F-GITA was returned to service, and the NTSB recommended the E&E bay shouldn't be positioned there in the next millennium...
