Originally Posted by
imaynotbeperfect
My understanding, I think was from one of Angus Houston's briefings, is that the ULB is not intended to be detectable at such depths. It is for finding the flight recorders once you have already found the debris field.
Having said that it does lead one to the conclusion that when it was introduced possibly there was no expectation that debris would be recoverable from somewhere as deep and remote as the southern Indian ocean.
This is absolutely correct the design was for cases such as when the debris was in a river - say the Potomac and the CVR/DFDR needed to be found. So what we have is a failure of systems analysis, what happens if an aircraft goes NORDO on the way to Hawaii and does not arrive? What about LAX - SYD? My suspicion is that the systems analysis was limited at the start by external inputs like funding, weight and the capabilities of the then systems. It is in urgent need of revisiting.