@Sultan,
I respectfully suggest that the account you offered of flight recorder performance in the helicopter accident reflects an imperfect recollection or interpretation of the events. I have two reasons for this:
1) Usually when buying a car, we don't ask, "does it have a motor, or is at least designed to be fitted with one?" ... because everyone understands that cars need motors! When specifying or designing a flight recorder, it ain't necessary to spell out "this thing should record data right up to final impact," because everyone knows that's the
FUNDAMENTAL PURPOSE of a flight recorder. N'est ce pas?
2) I have reviewed
Aviation Investigation Report A09A0016 issued by Canada's Transportation Safety Board, concerning the fatal ditching on 12 March 2009 of a Cougar Helicopters' Sikorsky S-92A.
This report says, "The MPFR* stopped recording about 44 seconds before impact and then began recording again about 1.7 seconds before the impact." The report attributes the data loss to an interruption of power to the recorder. Further, it finds that the likely cause of power interruption was activation of a
g-switch intended to stop flight recorders when a crash occurs (?!?!).
If this is indeed the accident to which you refer, and the report is correct, then about 42 seconds of data were lost. Much more importantly, the quoted statement implies (strongly, to my mind) that the recorder captured and stored data up to the time of power interruption, and that recording promptly resumed when power was restored.
The report makes no reference to recorder buffering, latency or delay as a cause of the flight data loss. The report's sole finding with respect to the flight recorder, is that the use of
g-switches to stop flight recorders is likely to result in data loss in future aviation incidents.
____________________________________________
If I've gotten any facts wrong, or misinterpreted anything, I welcome correction.
*Multi-Purpose Flight Recorder, a combination CVR/FDR