Program logic bugs vs input/environmental errors

[Paolo Invernizzi via Digitalmars-d]

On Friday, 3 October 2014 at 18:00:58 UTC, Piotrek wrote:
> On Friday, 3 October 2014 at 15:43:59 UTC, Sean Kelly wrote:
>
> This "real life" example:
>
> http://en.wikipedia.org/wiki/Air_France_Flight_447
>
> I just pick some interesting statements (there are other 
> factors described as well):
>
> "temporary inconsistency between the measured speeds, likely as 
> a result of the obstruction of the pitot tubes by ice crystals, 
> causing autopilot disconnection and reconfiguration to 
> alternate law;"
>
>
> And as I can see it, all subsystems related to the "small 
> failure" was shut down. But what is also important information 
> was not clearly provided to the pilots:
>
> "Despite the fact that they were aware that altitude was 
> declining rapidly, the pilots were unable to determine which 
> instruments to trust: it may have appeared to them that all 
> values were incoherent"
>
> "the cockpit lacked a clear display of the inconsistencies in 
> airspeed readings identified by the flight computers;"
>
> Piotrek

As one that has read the original report integrally, I think that 
you have taken a bad example: despite the autopilot was 
disengaged, the stall alarm ringed a pletora of times.

There's no real alternative to the disengagement of the autopilot 
is that fundamental parameter is compromised.

It took the captain only a few moment to understand the problem 
(read the voice-recording transcription), but it was too late...

---
/Paolo