Thanks for the responses, although, I would like it if I someone could confirm my answer. Here's an example:. .. .Heathrow ILS DME Rwy 09L 11-1. .I am a Category C aircraft with visibility above minimums, but the base of the fog layer is 285 feet MSL. I'm on the approach and as I approach 285 feet I see nothing...at 280 I see nothing, so I announce a go-around and commence it at the published DA of 279 feet MSL. I am a lazy pilot and the entire aproach was coupled and the aircraft naturally sinks slightly while transitioning from a descent to a climb. Am I safe (read legal) as long as I do not bust the OCA of 252 feet MSL which I read beside the profile view on the approach chart?. .. .Mere curiousity is killing me. I've asked a few check airmen buddies (US airlines) and they don't have an answer. Few of their approach charts have those numbers, and we don't have them over here.