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Old 15th Mar 2012, 22:20
  #836 (permalink)  
HazelNuts39
 
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Hi Lyman,
I'm impressed. Another quote from Interim Report #2:
1.6.11.3 Design and limit speeds
A certain number of speeds are represented by specifi c symbols on the PFD’s
speed scale (protection or design speeds – “green dot”, F, S, Vmax, Valpha prot, etc.).
Some of these speeds are calculated by the FMGEC, others by the PRIMs which
transmit them to the FMGEC for display. In the case where the three ADRs are
rejected by the PRIMs, the SPD LIM flag appears at the bottom right of the
speed scale. The current speed and the target speed remain on display. If at
least one ADR is valid in the FMGECs, the Vmax speed may remain displayed on
one side and/or the other.
We don't know if and when all three ADR were rejected by the FCPC's(*), but IMHO it is unlikely to have occurred before 02:11:40. The (second) stall warning was triggered at 02:10:51.

In your quote the part that reads "but the activation threshold of this warnng is indicated by a marker on the airspeed tape" is strictly speaking only correct for flight at 1g.

(*) In my understanding that condition triggers the ECAM message F/CTL ADR DISAGREE, which according to the ACARS transmissions was generated in the minute commencing at 02:12:00.

P.S. When the stall warning began at 02:10:51, the right PFD was showing 121 kt. The stall warning speed VSW would have been close to 216 kt, the speed shown on the left PFD while the LF was close to 1. In other words, VSW would have been off scale for the right PFD.

Last edited by HazelNuts39; 16th Mar 2012 at 09:01. Reason: P.S.
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