Weak Pingers
Graybeard,
You said "The return on investment in pingers has to be pretty poor".
How does one calculate that? If this pinger is not heard and it's required to use conventional methods to locate the CVR etc. the cost of that will likely be massive.
And if, heaven forbid, another Airbus is lost because we don't manage to learn the lessons of this loss the cost of that, both in human life and the plane, will outweigh a great many pingers.
Reading the posts here it's clear that far more information is needed. That can only come from retrieving the instruments. In any case can anyone tell us why we don't just have a massive 'ping' every hour? The listening gear on all Navy ships, especially submarines, is very sophisticated and would detect that, on a sensible sound frequency, very quickly.
Or have I missed something?