Contaminated runway
JAA says that a runway is contaminated when more than 25% of the runway surface area (whether isolated areas or not) within the required length and width being used is covered by the following:
- Surface water more than 3mm (0.125 in) deep, or by slush or loose snow, equivalent to more than 3mm (0.125 in) of water;
- Snow which has been compressed into a solid mass which resists further compression and will hold together or break into lumps if picked up (compacted snow); or,
- Ice, including wet ice.
The US FAA says that a runway is considered contaminated whenever standing water, ice, snow, slush, frost in any form, heavy rubber, or other substances are present.
Manufacturers are usually publishing a surface contamination in terms of equivalent water depth.
Airport operations on loose snow and slush covered runways are treated in a similar manner as operations on a runway contaminated with standing water.
Have a good one.