DA/H, Where is it defined?

[Treeclipper]

Hi,

I am looking for an ICAO or EASA document that defines and establishes the DA/H for PAs and the MDA/H for NPAs

ICAO Annex 6, Volume One states:

Category I (CAT I) operation.
A precision instrument approach and landing with:
a) a decision height not lower than 60 m (200 ft); and
b) with either a visibility not less than 800 m or a runway visual range not less than 550 m.

(this exact definition is also used in EU OPS (965/2012) )

Where did they base 200' on, and when you decide you require more than 200', what do you base it on?
It is the OCA/H plus various margins, but which?

That must be surely specified in one of the documents, but which one?

Cheers!

[oggers]

Sounds like you are looking for PANSOPS or TERPS

[Bluescan]

As Oggers said, have a look in the PANS or TERPS.

ICAO has produced PANS-OPS (ICAO Doc 8168), Procedures for Air Navigation Services, Aircraft Operations. It is devided into two volumes:
- Volume I — Flight Procedures* (http://code7700.com/pdfs/icao_doc_8168_vol_1.pdf)
- Volume II— Construction of Visual and Instrument Flight Procedures* (http://code7700.com/pdfs/icao_doc_8168_vol2.pdf) (This is probably the one you are looking for in your question)
PANS-OPS are used in Europe and most other countries.


USA and some other countries uses TERPS (http://www.faa.gov/regulations_policies/orders_notices/index.cfm/go/document.information/documentID/1029266). These include Canada, Korea, Saudi Arabia and Taiwan. These procedures are in many ways similar to ICAO PANS, but there are some differences (especially regarding circling approaches).


*Unofficial source.

[underfire]

Deconstruction the foundation of the calculations, the baseline variables use a 200' ROC, a 50' TCH, ISA temp, and a GPA of 3 degrees.
The GPA line goes though the TCH point, this is the foundation point for the 200' ROC. (so at the TCH, the ROC is 200' below this point)
The ROC tapers from this point, to a 500' ROC at the FAF. (this is what sets the location of the FAF, when the ROC is 500')
This missed approach surface origin is where the ROC intercepts the ASBL which is a projected line level with the RWY.
The intersection of the approach and missed approach used, some using the actual point, while others add a 50' momentary descent.

http://i.imgur.com/eFvGA72.jpg

If you have obstacles, it can raise these surfaces. (blue is high temp correction)

http://i.imgur.com/fCKYRyU.jpg

You will not find the "definition" of why it is a 200' or 250' anywhere other than that is what it is. It took deconstruction of the formulas to figure this out.