Originally Posted by airfoilmod
It may not be clear to some that cavitation was caused by events just prior to the incident, but that is exactly what Boeing Captain Carbaugh suggested and AAIB is looking for a "restriction in the Fuel system upstream as a cause of the cavitation." See post #662 and the flightglobal.com article (3-14-08) quoting Dave Carbaugh.
I agree that it is a likely scenario, and it fits the rest of the scenario just fine, an upstream fuel flow restriction, causing both pump cavitation and restricted flow (the former possibly exacerbating the latter). All I was saying is that we (in the uninformed public) do not (yet)
know at what point in time the cavitation occurred that caused the visible signs. This is a matter of level of confidence in the factors in our causal reasoning. If I were to make a Why-Because-Graph of this, pump cavitation would be marked as an "Assumption".
Note that even the flightglobal article talks about a "
possible" fuel flow restriction, and that the cavitation signs "
might indicate" such a restriction. The assessment that the cavitation occurred "
not long before the impact" has not yet been publicly supported by facts. It is so far just an assumption, useful for creating test scenarios, but it should not be confused with an established fact.
It may be a linguistics issue, saying cavitation couldn't be the "cause of Fuel Starvation", but it certainly would show a "restriction upstream" as evidenced by damage to pump lobes. Said restriction might be the "proximate cause of the lack of Fuel". Carbaugh said the cavitation might have been caused BY restriction, making the pump damage a RESULT of restriction. (He also mentioned ice in fuel and made reference to "temperature").
Yes, I almost completely agree. Except that it's not a linguistic issue, but an issue of causality.
My previous comments were in response to skridlov asking (linguistically unambiguous) why cavitation could not be a sufficient cause in itself.
Bernd