PJ2,
Lyman,
Hambert Sprinkleman,
I did a little research on UAS and came up with some interesting results. It would appear the accident investigation and reporting agencies tend to use the term "Erroneous Airspeed Indications". This is true in the Aeroperu and Birgenair reports as well as one issued by the US NTSB on an incident over Kansas City involving a B-717 which did not crash. These reports were issued prior to or around the time of AF447.
However, there is an FAA document that was issued to discuss this phenomenon:
Date: 6/26/75
Initiated By: AFS-223
AC No.: 91- 43
Subject: UNRELIABLE AIRSPEED INDICATIONS
I would say, in terms of the English language, errorneous airspeed meaning is pretty clear, the airspeed was wrong. Unreliable airspeed is a little "softer" as its meaning is "don't count on it to be accurate or uncertain of accuracy".
Lyman, In a court of law, I suspect the terminology of either poses a problem for the defendant.