* Posts by Just an aerospace engineer

1 post • joined 26 Feb 2008

Heathrow 777 crash: 'No anomalies in the major aircraft systems'

Just an aerospace engineer
Dead Vulture

The man has something

Brian Morrisons comments seem about the only plausible explanation I have seen. If the pumps show sign of cavitation then at some point they have been operated with insufficient fuel, I suspect that if the aircraft had operated with one or more tanks at low level in the past, the main obvious reason for insufficient fuel, it would have been an event that the flight crew would have logged and would have been picked by the AAIB. Although nothing is guarenteed on this planet if the Quick Access and FDR show systems demanding full throttle with correct fuel valve and pump commands then I would believe the systems tried do do what was requested - generally these data are monitored tale backs i.e. the actual commands provided to LRUs and not "internal" software variables i.e. for example the FDR wouldn't log what the FADEC said it was commanding but would log the "real" used command being sent. In anycase although FADECs are almost unique in not being dissimilar (I await the emails on this subject....) the idea that the same common mode failure could occur on different engines at different times with almost certainly some distribution in engine and throttle states is pretty far fetched (not impossible but certainly not as plausible as Brians explanation). But in anycase I am sure it will prove to be something else ...

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