FODCOM 03/2009 is kind of interesting in that UK AOC Operators may not treat a Wet grooved runway as Dry, but the rest of Europe does - are we now into the scenario where UK AOC Operators can't land but other European AOC Operators can?
"I no longer fly with ze crazy British Airline, when it rains we cannot land"
So much for the level playing field in Europe brought about by EU-OPS.
It is interesting to note that in 2003 JAR-25.109(d) (Now CS-25) (well after JAR-OPS) was amended to include "Wet Grooved performance", which can be calculated on the basis that braking action on Wet grooved runway is seven times better than wet braking action on a smooth wet runway (Dry braking action is ten times better than that on a smooth wet runway). From the wording in JAR-25 and CS-25 wet grooved performance can be calculated, rather than flight testing required. Ideally manufacturers should retrospectively amend aircraft flight manuals to reflect this.