one of the following substances on the surface of the runway: (a) compacted snow: snow that has been compacted into a solid mass such that aeroplane tyres, at operating pressures and loadings, will ru, üks järgmistest rajakattel esinevatest ainetest: , a) , kokkusurutud lumi: tahkeks massiks kokku surutud lumi, mille pinnal lennukirehvid töörõhu ja -koormuse juures sõidavad, ilma et need suruksid