ICAO Weather Decoder (ATPL 050)
In a METAR, FEW (1-2 octas) and SCT (3-4 octas) are reported but do not constitute a ceiling. A Ceiling is defined as the lowest layer of BKN (5-7 octas) or OVC (8 octas). If a ceiling is below 1,500 ft or visibility is below 5 km, it is no longer CAVOK.