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After an aircraft incident, finding the black box is important to investigate the causes, because it contains a lot of valuable recorded data. The process of locating this can take a lot of time, and perhaps in some cases it will not be found at all, or deliberately sabotaged. Both problems could be mitigated by continuously streaming flight data through a satellite uplink — or, if there is no coverage, buffer the data until there is.
Do any aircraft do so, or are there any serious proposals to start doing so in the future? What would be the largest obstacles?