I have a blog post that covers this in more detail.
@Airborne_again thanks this blog is very useful
Thanks everyone, much clearer to me now!
There are some differences between the EASA paradigm and the ICAO paradigm. Both
According to ICAO (as quoted by @roznet),
In the EASA regulation (NCO.OP.111)
Jepp’s terminology is a legacy from an era of even more confusion and is rather complicated.
Briefing_Bulletin_JEP_15_A_Announcement_AOM_Concept_23_AUG_19_pdf
This stuff is so obscure. It’s no wonder almost nobody understands it. The “margin” is supposed to be in the aircraft POH, but on older ones it won’t be, and some just don’t have an add-on (the TB20 is one such; which my CAA IR examiner in 2011 thought interesting).
I always thought a precision approach (ILS or LPV) is called “DA” and everything else is called “MDA”, but one always flies down to what is on the Jepp plate.
The above suggests that a +V is also “DA” which makes sense because for all practical purposes it is same as LPV.
Peter wrote:
This stuff is so obscure. It’s no wonder almost nobody understands it.
The was the case for several years when things were in transition and then it was indeed a mess. But by now things are rather straightforward and it is not difficult to find good information if you really want to.
The “margin” is supposed to be in the aircraft POH, but on older ones it won’t be, and some just don’t have an add-on (the TB20 is one such; which my CAA IR examiner in 2011 thought interesting).
Are you thinking of the altimeter position error correction? That indeed should be in the POH if relevant, but the interest in that seems limited to the UK. I have never heard anyone from another country discuss that issue. The margin we’re discussing here is what is made necessary because an aircraft can’t instantaneously transition from descent to climb. That margin in included in the procedure design and depends on the aircraft approach category,
I always thought a precision approach (ILS or LPV) is called “DA” and everything else is called “MDA”, but one always flies down to what is on the Jepp plate.
The above suggests that a +V is also “DA” which makes sense because for all practical purposes it is same as LPV.
The choice between DA and MDA depends on the flight technique. If you are in a continuous descent during the whole final approach, as you are with a 3D approach or a 2D approach flown with the CDFA technique, then you use DA. If you fly a 2D approach with the “dive ’n drive” technique, then you use an MDA.
So a +V uses a DA because it is a 2D approach flown CDFA using the advisory glidepath.
In addition to PEC (if not stated the practice is to use 50’, although the DA42 states 25’ in the AFM for example) there is temperature correction when the METAR is at zero C or below.
RobertL18C wrote:
there is temperature correction when the METAR is at zero C or below.
That’s uncontroversial… At least for us who live at 60°N. 
bookworm wrote:
In the EASA regulation (NCO.OP.111)a CDFA flown with continuously displayed vertical guidance (e.g. LNAV+V) is a 3D approach operation and is flown to a DA/DH which may be as low as the OCA/H
a CDFA flown with manual calculation of the required rate of descent is a 2D approach operation and is flown to a DA/DH which may be as low as the OCA/H
an NPA flown by the stepdown technique is a 2D approach operation and is flown to an MDA/DH
That’s interesting and correct:
That’s interesting and correct
Always good to see hazek concur with an expert 
It’s always good to see the regulation match what an expert says. I indeed like that.
Innit cool – what wonderful conversation copy & paste allows ? ;-)
