Numerous news reports about the recovery of QZ8501's flight data recorder say it might take up to a month to read the data. Can anyone tell me if this is true and why it takes so long, especially if the FDR is intact, as this one seems to be?
If the FDR is in great condition then the data readout will be quick (hours or days).
Even so, after the data has been downloaded, all the information collected must then be validated / checked for quality. E.g., suppose we read out a series of sidestick movements -- how do we know that those were the actual movements of the sidestick, and not representing a sensor malfunction, or perhaps a recording error from the FDR itself?
There are hundreds of parameters which much be checked for correctness. Normally this quality check can be completed quickly as well, but in cases of discrepancy it can take many months to fully validate the data.
Various regulations stipulate that each FDR/CVR must be checked and analyzed for data quality (including a full-flight parameter readout) at least once every 12 months. Unfortunately there have been recorder errors undetected until after an accident, making retrieval & analysis a very long and tedious process.