Originally Posted by
gonebutnotforgotten
OK, I give up, if these pings came from the searching ship(s), why did they disappear, roughly at a time when the original locator batteries were expected to die?
There seems to be a common thread here.
The ULB, is at a frequency where its range is less than the ocean depths over which aircraft routinely fly
The ULB battery life is insufficient for a search and recovery operation in remote areas - such as over the ocean
The ULB is not encoded so a ping has to be assumed to come from a ULB based on its frequency and recurrence frequency
The CVR with the voice data is shorter than the oceanic flights routinely made and only records sounds not what is happening in the cockpit
The DFDR does not record the output to the pilots on the assumption that both sets of instruments are receiving and displaying the same data
etc etc
This discussion of pings by subject matter experts reminds me of similar discussions by other subject matter experts on 'what that noise was' on CVR recordings. Or the discussion on the data actually shown to the PF rather than the PNF
This is poor systems analysis. These 'black boxes' are literally not fit for their purpose in multiple ways. Not only have recording and data communication capabilities vastly increased but also the type of flying has changed with aircraft commonly flying 'thin routes' over sparsely populated areas including all oceans and the poles. Rather than a piecemeal approach to fixing shortcomings (or demanding that they are not fixed), it is time that the industry started a complete reappraisal of the areas such as recordings, emergency location, aircraft tracking, survivable recording devices; and generated a formal functional requirement that included
all of these issues in one overarching specification. This is a job that ICAO, RTCA, EUROCAE and other standards bodies should take on urgently.