Several questions regarding the NAV ADR DISAGREE message have been lingering in my mind. The ACARS message was time-stamped 0212 and it was received by the ground station at 02:12:51. The 3rd interim report lets it appear on the ECAM at 02:12:XX and the final report at 02:12:44. What new information permitted the more precise timing?
What caused the message at this point in time? The Air Caraibes memo states the thresholds for rejection of the first ADR as: Altitude 3000 ft during 1 second, Mach 0.05 / 10 s, CAS 16 kt / 10 s, TAS 16 kt / 10 s, AoA 3.6° / 1 s, total pressure 20 hPa / 10 s, static pressure 5 hPa / 1 s. The thresholds for rejection of the two remaining ADRs are the same except that the time is always 1 second.
Then the ECAM message (final report, page 99):
NAV ADR DISAGREE
- AIR SPD ...... X CHECK
- IF NO SPD DISAGREE
-AOA DISCREPANCY
- IF SPD DISAGREE
-ADR CHECK PROC ... APPLY
Isn't it odd that the system asks the crew to find out what caused the system to generate that message? If there is NO SPD DISAGREE, the crew is to suspect AOA DISCREPANCY?