Okay, this has in my experience always beem a bit of a grey area, my company ops manual says, quite rightly that is is difficult to define some of these conditions. But in these days of litigation.....
So lets see if I can summarise so far; more than 25% of the runway and more than 3mm of water or slush appears to be the figures that most operators consider contaminated. Dry snow is often another matter.
The runway can be classified as dry, damp, wet of contaminated (or flooded).
The actual braking action can be measured be a variety in instruments.
So what about these phases such as "slippery when wet" and "rubber deposits" and their effect on operation?
(LGW was promulgated as slippery when wet īcos of resurfacing)
What if a previously landing pilot reports the runway as "slippery", is that then legally binding, ie slippery landing data, cross wind limits etc?
What if you are the first to land for some time and no pilot reports are available?
Are ATC responsible (around the world) to notify the crew of the state of the runway?