Lets pause and examine the reason why this discussion is taking place.
An aircraft has been lost over oceanic airspace and we have the privilege of knowing, due to the transmission of AOC/ACARS messages via Inmarsat, where it was at 2009-06-01 02:10:30z and that it was still flying for at least 4 minutes later.
We do know from forensic examination that the aircraft had a very high rate of descent with a small but positive attitude when it impacted the water. We do know that if the DFDR and CVR can be located that a more conclusive resolution as to the actual cause and handling of the mishap will be established. We do know that no ELT was activated, and that the ULB pingers were not detected and that the time for doing so expired 30 - 40 days after their activation.
What we don't know is where its flight ended and though many pieces of debris along with 50 bodies have been recovered, they were not located for at least 5.5 days after the accident.
What we really want to know is where the aircraft was within say 30 seconds of its demise, as the problem relates to the last known GS which means that it could have moved in any direction at up to 8NM per minute. What we also know is that the area of the search will increase by the square of the time difference between the last known position and its impact position. Reducing the time between position reports also has the advantage of reducing the search area even further, as the probable direction and speed of flight will be known with a likewise diminishing percentage of error.
The answers to all the so-far unknown events have been carried with the aircraft to the depths of the equatorial North Atlantic, and we know once we can locate and recover the recorders those unknowns will become known. We also need to know where the wreckage is as it may be necessary to recover parts of it to complete the crash analysis.
So, having established the known and unknown issues, we need consider whether the duplication of flight data parameters, duly recorded in the DFDR/CVR, in a real-time radio data stream by any available means is ultimately cost effective. Not only that, but what will be the time scale and cost of effecting such a mammoth change to a whole industry, when only a small proportion of the worlds fleets are regularly flying outside of SSR coverage in Oceanic FIRs.
Perhaps it is time to be reminded again that the Final Report of the Flight Data Recovery Working Group -
Flight Data Recovery Working Group Report
established fairly sound guidelines to the practicality or otherwise of the means proposed. The "near to" or "short term" solutions are:-
(a)..Increased autonomy of ULBs (90 days instead of 30 days), and
(b)..Use of a lower frequency (~9kHz) for ULBs attached to the aircraft.
Any recommendations regarding real-time data streaming are essentially a long way off.
In respect of position reports, this
post made a proposal that can and should be implemented "now" by SATCOM equipped aircraft.
mm43