"Speed" is not as descriptive as "Airspeed", and at each opportunity to quantify the problem the manufacturer continued to use full script.
I'm supprised the manufacturer hasn't adopted "airspeed" in its "unreliable speed" procedure description. Lets face it, ground speed has limited application, i.e. navigational, along with determining windspeed, and taxiing. So to that end, "Airspeed" is the number that counts from V1 in the takeoff roll until passing a similar point in the landing rollout, and it follows that if it becomes "Unreliable", UAS is the acronym of choice.
Reverting back to Robert's comment, "We've lost the 'speeds'" and Bonin's far from unequivocal response, leads me to suspect that Bonin was focused on an earlier discussion with the Capt in which his desire to go higher was rejected on account of the REC MAX limitations due to high OAT. Well, he got his way and went higher, and as we now know the aircraft would have survived at FL380 if it had been "flown" there.
I use "flown" in a sarcastic sense, as the FDR/CVR transcripts (that we have) indicate little evidence of the true meaning of the word.
Passages in the CVR transcript where the words, "You're going up" and "I'm going down?", and similar variations makes one wonder if these two pilots were actually in the same aircraft! It has been stated often in these threads that we do not "know" what Bonin saw on his PFD, but as there were no anomalies on the the PFD's prior to 02:10:05 it is reasonable to expect the same prevailed for the rest of the flight. What we do not "know" and never will, is how Bonin interpreted what he saw. We do "know" what he did. Responsibility for the safe conduct of the flight and what happened that night lies with the Captain, and decisions he made prior to taking his rest period are all relevant.
Hopefully the BEA will have managed to extract some data from the recovered QAR that will provide closure to this matter.
The BEA's factual Final Report will of course lead to the "blame game", where the roll that either of the pilots played in this accident will be sheeted home to rest with those with the deepest pockets. A rather cynical outcome to an accident that I believe ultimately revolves around "human factors" of which all three pilots in one way or another were involved.