pp - we've had this discussion recently here! Have a look
here. Note the
link to the Jepp info. There is more bedtime reading
here As '737jock' says, there is now the option in EU-OPS anyway of establishing a
DA for an NPA which will not cause the a/c to descend below a safe obstacle clearance during a g/a. It will be company specific in the OM and some may take a while to change. Note the 'divers and drivers' are required to increase min RVR for their approaches.
As 'backofthedrag' says the whole definition of 'MDA' was that you could not go below it in a g/a and hence the (various) additions for different a/c in different OMs (50' in my lifetime). MDA was an abbreviation for Minimum
DESCENT altitude ( not
DECISION). Obviously a change to a 'real' DA will need a review of the figures used. It will certainly make like easier at the sharp end.
I believe implementation of the new system has to be sometime in 2011.
Like many things 'European' it is riddled with scope for confusion!