Pitot Probability
Back to the discussion of why the ACARS wasn't consulted first when the plane was overdue:
I remember reading early on that Maintenance in CDG noted the Airspeed fails reported by ACARS, and moved the plane that was AF447 up in priority to get the new pitots upon arrival.
It would be easy enough to automatically alert company Dispatch whenever a Flight Essential or Flight Critical component were flagged over ACARS. Also, maybe the ACARS should be programmed to transmit every minute as long as there is a Critical component flagged as failed?
Regarding Satcom vs. HF data transmission: the link is error-free, when it's working. HF works everywhere beyond VHF range, and is pennies to dollars less expensive than Satcom. HF continues to evolve, and a major data rate improvement was announced recently by Collins.