A320 & Contamined Runways

[che ci dō che ci dō!]

Hi everybody,

I've a few questions concerning operations on contamined runways with A320. In the FCOM performance calculations for take off and landing are done only as a function of type of contamination and depth. Friction coefficient is taken into consideration only for max xwind limit.

- Why in the FCOM there're no performance calculations as a function of the friction coefficient? is it because the certification requirements don't call for it?

- It may happen to plan a take off from a runway covered for instance with 2mm of dry snow and a reported friction coefficient below 0,25. From the performance point of view this type and depth of contamination is equivalent to a wet runway but for sure the runway distance required to stop the a/c in case of RTO would be much higher. What's the best way to do a precise planning in these conditions?

Thanks