AF447 : un accident d'une extraordinaire complexité
certification:
BEA:
The A330 meets the requirements of the regulations in force at the time of application for the license type, namely the JAR 25 change 13 or 14 and the special conditions issued by the DGCA.
...
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.
ECAM on the AF447, for 2 minutes and 39 seconds there was no message NAV ADR DISAGREE or NAV ADR DISCREPANCY.
It is these messages that moving towards doubtful IAS, procedure adapted to the situation