I don't know whether it's the same today, but those who only held White Ratings used to have to add 200 ft to the calculated DH.
The minimum DH was 200 ft, so the minimum White Rated DH was 400 ft. In YLO1, with a 500 ft minimum ceiling, no problemo. But with YLO2 having a 300 ft minimum ceiling, if it was OVC a White Rated pilot couldn't get in.
Hence a rule of thumb that YLO1 and better was OK for White Rated mates, whilst YLO2 was OK for G/MG - the subdivision of YLO was very useful.
Last edited by BEagle; 10th Feb 2013 at 10:04.