SO, back to ISIS and Ranamin's and my question. A33Zab appears to show that aguadalte's posts are incorrect, and that ISIS does have its own IRS system and should be capable of providing basic attitude info in the event of failure (or isolation) of all 3 ADIRUs. The $10,000 question, of course, is what 'interference' does the aircraft 'management' software place in the way of ISIS ACHIEVING this aim? 'icarusone' and AZ tell us that it is possible that the Hot battery bus supply could have been 'interrupted' due to the air/ground switching (was 'ESS' unaffected?), and of course there would appear to be no heading info with loss of the 2 ADIRUs, so back to the standby compass
.
No, this does not 'solve' the accident by any means, but if the ISIS was somehow 'prevented' from providing this basic information it makes an accident far more understandable given the other system failures they
appear to have suffered in those weather conditions. The whole software side is indisbutably very clever, but IF it has been coded on the basis that there are so many redundancies and backups that 'nothing can go wrong', is it time for a big red switch which says 'take ALL the computers out of this and give us Basic information so
we can try to fly it'? NB That is for ALL modern aircraft of whatever type/manufacture.
Lots of fingers crossed for the search.
A different question for those familiar with that route. From what I can make out in terms of where this might have occurred in the actual area of CB activity, carrying on on track after 'recovery' from whatever happened would appear to be a better weather solution than turning back to the mainland. How would this fit with a possible 'worse case' ETOPS fuel scenario ie low level 2 engines vis a vis ETPs and excess fuel, and where would ETP 1 be likely to be in relation to TASIL?