Originally Posted by
TWOTBAGS
...My opinion in this case is for whatever reason the ferry set up would not feed the main tanks, The crew exhausted there mains and were screwed after that.
I agree, that sounds like the most likely cause of the fuel exhaustion. The numbers support your hypothesis (the time spent aloft prior to ditching).
I've done dozens of intercontinental ferry flights with the factory ferry fuel system installed. The most prudent way to manage fuel is to replenish the main tanks - by gravity feed - from the ferry system before reaching any PNR along the route.
Other ferry fuel systems, different from the factory system, have been used by operators and ferry service providers. These
Rube Goldberg setups use bladders and an electric pump to transfer fuel, rather than the stainless steel drums and gravity flow that the factory system uses. I have never seen an accident report that cited "failure of gravity" as an accident cause.