Water = 3 mm
Ice or compacted snow = measurement not given
There is a limitation of when you cannot take off;
Dry ice/ dry snow/ wet snow
How much?
More than 15 mm of WET SNOW or WATER
More than 60 mm of DRY SNOW
More than 80 mm of VERY DRY SNOW
115% of runway is required if the runway is contaminated for destination.
3 types of hydroplaning;
1) Dynamic
2) Viscous
3) Reverted Rubber (eat on your own tyre)
For non-rotating tyre;
Viscous; 7.7 x square root of the tyre pressure in PSI
Dynamic; 9 x square root of the tyre pressure (if in bars x 14.7)
Coefficients of Friction
0.4 and above = good = 5
0.39 to 0.36 = medium to good = 4
0.35 to 0.30 = medium = 3
0.29 to 0.26 = medium to poor = 2
0.25 and below = poor = 1