Giovanni:
Can't understand the zoom climb thing either. Try flying around with a cup of coffee on the floor. Unless it's turbulent in virtually all manoeuvres you won't spill a drop!
The EC 135 sounds as if it has a similar fuel system to the BO105. In the case of the BO, the supply tanks are in
front of the main, and they are of equal size so that if the transfer pumps fail both engines will quit within seconds of each other.
When checking out in the BO, we were told of a tall pilot who left his transfer pumps off and subsequently had a dual engine failure because the glareshield of that particular ship blocked his view of the "FUEL LOW" caption. We were told that you might have approx. 20 minutes to flameout in such a case. (I might add here that I remember thinking the requisite
"Oh, that'll never happen to ME!") As a hedge against such a brain fart, I got into the habit of always without fail leaving the transfer pump switches on and NEVER shutting them off.
One day, I was shut down, showing another pilot the avionics suite in my ship. To save battery power I had turned the transfer pumps off. You guessed it, I forgot to turn them on at startup next time. I had been airborne for fifteen or twenty minutes, cruising along, fat dumb and happy when I began idly looking around the cabin for no specific reason. When my eyes spied the transfer pump switches, I about had a heart attack.
YIKES! The "FUEL LOW" light was not on, and my supply tank quantity gage still showed full. What the...?
Apparently, the ten-degree nose-down attitude of the BO in cruise flight kept enough fuel gravity-feeding from the Main into the Supplies. Or something like that. Whatever, it worked I became forever grateful for that rigid rotor and uncomfortable cruise attitude that I had previously cursed.
Long way of saying, I guess, that a full cup of coffee
will spill in a BO105, and that there are ways of getting fuel to transfer other than electronically-assisted.