Link to CS-27
http://easa.europa.eu/system/files/d...ndment%203.pdf
Lets read all of it:
(b) Fuel transfer systems. If normal operation of the fuel system requieres fuel to be transferred to an engine feed tank, the transfer must occur automatically via a system which has been shown to maintain the fuel level in the engine feed tank witihin acceptable limits during flight or surface operation of the rotorcraft.
Lets look at it this way:
As soon as you turn on the fuel transfer pumps in the EC135, the fuel is transferred
automatically via the system,
this system has been shown to maintain the fuel level in the engine feed tank within acceptable limits during flight or surface operation of the EC135.
Example: Nothing automatic about the autopilot until you switch it on.