Green Dot, you are right. It's a pity Top Bunk's information is not more specific: perhaps it does in fact refer to the HP Pump (independently on each engine, with an interval of a mere 8 seconds). Hmmm.
By the way, I think you meant "gravity feed" rather than "suction feed"? Wasn't it you and Swedish Steve who proved a long time back in this thread that we are talking about wing tanks? And the aircraft was at sea-level, with plenty of atmospheric pressure available.
Quote from pacplayer [yesterday, 1212z]:
You keep talking about what fadec is designed to do from the factory. That's not the context of the conversation I was attempting to delve into. A rollback is a well-documented software created anomaly, as I understand it, in which, for whatever reason the fadec has either miscalculated the thrust solution (thinks it's at high power and stays at idle) or has had a dual failure of both channels and is presumably trying to reboot itself at idle (since both channels are susceptible to the same software bug.)
[Unquote]
I would be very surprised if both channels are susceptible to the same bug. Although Boeing decided not to follow Airbus's lead, I believe, in trying to create and segregate two independent software design teams, they would have done their utmost to avoid this obvious trap.
Chris