Baro-Vnav and Approach Minimums
 

When using Baro-Vnav for RNAV Approaches, when is your approach minimum a Decision Altitude (D.A.) or a Minimum Descent Altitude (MDA). Thank you.

If the chart has a VNAV line of minimums, you use DA.

Can someone please explain: some operators/XAA's have an add-on to MDA, as this allows for a 'sink factor' during the GA. They still insist having the same add-on when using a DA, yet I thought this includes a 'sink factor'. Why is this, or is it simply standardisation to avoid forgetting it?

That add-on is supposed to be for MDAs that are treated as DAs. The sink factor is considered in criteria for charted DAs.

Unfortunately while this is supposed to be the case it is not universally true. Some countries/airports have just changed the label without reassessing the approach.
In Europe, the onus is on the operator (as always!) to find this out for every approach they might use. This leads to many smaller operators and pretty much all ad-hoc charter companies just continuing to add the sink margin even if the plate says DA. The resource required to do the assessment far outweighs the benefit, since how often will that 50 feet make the difference?

Pathetic, isn't it.

Thanks aterpster.

I guess that if you are on a CDFA is like descending from the VDP. If you start your descent from the VDP and the ATC ask you to Go Around due to any reason or you decide to Go Around, you will not have an accident. NPA are flown ILS alike these days. So no harm in making the MDA a DA. Also no need to add on.