Nick, Thanks your response, is educational as I was expecting.
I'm flying Bell-412EP.
Certainly the altitude restriction it isn't a big issue, because the possibility of a double boost pump faiure I would like to think that is remote.
But the leaks in a post-crash...
So you don't need the boosts pumps in the 92 even for startup , from a possibly empty line from de cells to the engine pump?
HeliComparator
The 92 design philosophy and Nick's comments are based on the fact that any leak in the fuel lines up to the engine will cause fuel to be pumped out, possibly into the cabin. This is clearly a bad thing and especially an issue in a crash, so addressing this issue by removing the booster pumps seems a good idea.
there is a down side. The problem is that air has a very much lower viscosity than fuel. So a tiny leak, which would cause a few annoying drips of fuel in a booster pumped system, in a non - booster pumped system can allow enough air to be sucked in to flame the engine out.
Don't you would prefer the engine out than the fuel leak?
Having seen the good outcome in the 92 and my little experience with the 412EP(regarding OEI) I would choose the "no-pump" system.
But... what do I know?
Best regards.
Aser