Hi Paco,
to make things clearer for the ones not familiar with the EC135:
so with everything going according to plan, one should have an idea, where how much fuel is and if the supplys are going empty with fuel still in the main tank.
B U T ....
things can go wrong - and information gathering can be be difficult, when busy with other things....
Lets see, what the final findings are and what we can learn from that.