I.e. BADLY! This redundancy implementation is USELESS specially at "cruise FL". Or worse, creating a CRTICAL design.
The use of a "voting scheme" capable to "major a/c reconfig" using identical (sub heated) not adequate Pitotīs is a direct path to PROBLEMS!
The System design managers that accepted this as a reliable System (fault tolerant) from the engineering team IMO DID NOT realize the OVERALL SYSTEM (aircraft+pilot) departed from the VERY IMPORTANT "graceful degradation" goal. It seems "bit oriented Engineers" concerned (absolutely justifiable) with computer systems (obviously requiring redundancy) induced to a "concept error" wrt to the AS measurements; To Project managers concerned (absolutely justifiably) with the importance of AS measurements for this design.
This a/c design IMO (wrt AS) is flawed in:
1) Ridiculous AS sensors redundancy (useless)*
2) The use of this voting scheme to not adequate AS sensors (sub heated)
Note: IMO this design EXACERBATES Pitotīs icing susceptibility
* Exception at TMA FL when one may mention chances of birds collision. I am not considering Pitot heater failure. We can discuss this aspect later.
Who can tell me why they implemented this redundancy in respect to AS measurements? I would like to understand the reason.
AF delay in replacing Pitotīs obviously contributed (to Murphy Law
) but is not as serious imo compared to Airbus SAS (and Certification) failure.
It seems to me (as a technician) that the bureaucrats are in charge. And the pilotīs being informed they are using a redundant, etc. (advanced design).
I hope for a review of this issue (in every "advanced a/c") using this. Even with super heated Pitotīs i never would adopt this.