Furious Assault is a special rule for Ravenguard in the Horus Heresy Books. While I am sure that most people are playing it as furious charge, there is no furious assault rule or listing for what it does. I am sure most people are playing it that way, but without a FAQ or Errata on it, its difficult to say for sure what the designers had in mind.
Here is Forgeworld's Response to Furious Assault
via a Reader here on Faeit 212
Just throwing this out as an fyi, I emailed fw asking for clarification on the legion rules for the Raven Guard in HH3:Massacre. In the book it was written that bikes, jump infantry, and terminators all received the Furious Assault special rule, however no such rule exists in 40k , not did they give a description of what it did. So here's the official answer from Forge World:
"Hi there. This should refer to Furious Charge so please treat it as such.
If there is anything further we can do to assist you, or if you have any
queries about the information we have requested or provided, please
telephone us.
Regards,
Forge World"