DA is the height at which the decision is made, and the go-around is initiated if the visual references have not been acquired. However, MDA still exists for non-precision approaches, especially in US. There are fewer depicted these days on Jeppesen charts, because on most NPAs, step downs and MDAs have been replaced with CDFAs and Das, which are better for noise abatement, fuel consumption etc for commercial fixed-wing operators. It is still an area which is poorly understood as to what we can and cannot do in a helicopter for NPAs. e.g. can you level off at the depicted DA and continue to the MAPt in the traditional manner? Do you have to add a figure to the published DA to level off at if you are going to do this, and where do you get this figure from? etc