Originally Posted by PJ2
On your question regarding disengagement of the AFS, I suspect that the AP - A/THR disengagement occurred two seconds before the loss of airspeed because the Mach parameter dropped to M0.30 for one sample, two seconds prior to the CAS dropping and the engagement conditions for the AP-A/THR-FD systems were temporarily not met.
That's another intriguing thing. The ADR's calculate Mach and CAS quasi-simultaneously from the same pitot and static pressures. Why would there be a delay of two seconds between Mach and CAS?
From Interim Report no.2:
1.6.11.6 Consequences of a drop in the measured total pressure
The static pressure (Ps), total pressure (Pt) and total air temperature (TAT) allow the ADR to calculate the following parameters in particular:
Standard altitude
Mach
Calibrated Air Speed (CAS)
True Air Speed (TAS)
The order in which these different parameters are calculated is not immaterial because the value of the measured static pressure must be corrected to take into account the measurement error due to the air flow disturbances in the vicinity of the sensor. This correction depends in particular on the Mach and has a direct influence on the standard altitude which only depends on the static pressure. On an A330-200 in cruise flight, the measured static pressure overestimates the real static pressure. If Pt and Ps are known, it is possible to calculate a Mach value that provides access to the correction of Ps. The Ps thus corrected is then used to calculate the CAS and the altitude.