Thanks again for ongoing inputs, tyropicard.
Well regarding the statistical failure probabilities I get a pain the proverbial and to my knowledge there have been at least two tripple IR failures, caused by explosiv nosegear-tire failures. The resulting accelerations when the debris hit the fuselage was outside the scope of what the internal algorithms of the IRs considered valid signals and thus all 3 units where 'faulted' - during rotation.
Although that happened on A310/A300s and there was a mod with respect to altering the mounting positions of the IRs (which formerly were located close to each other) that's enough for me to question the 'highly unlikely' part of the message, especially if it comes from AI.
Commenting further on the topic, regulating A/SKID with reference to tire/wheel speed might work on RWY surfaces with sufficient friction. As soon as it becomes slippery (wet or even worse) and there is seriuos work for the A/Skid there might be a problem. Unfortunately under these conditions a factor of >2 might keep you running out of options rather quickly on a heavy A321 in wintertime, especially if you don't know what kind of braking you're gonna have left.
As I understand our engineers are having a hard time and the phone lines to southern france are pretty busy this time.
Regards, MAX