So we agree that nothing indicated a speed value problem on ECAM before 2 min 39s after the AP disconnected
And JAR 25
In particular, they state that:
... Systems and associated alarms must be developed to minimize the risk of error by the crew;
means of information must be set up to alert the crew of the occurrence of a failure and enable them to take appropriate action.
Is 2 min 39S is a acceptable delay for indicate such problem ? (speed reading)