DB
You seem to be agreeing that the DA figure in brackets is the relevant height, and that the 225 systems bear this out.
My argument is that the figure in brackets is in effect a conversion of the DA (bar alt) and therefore may NOT be the ACTUAL height displayed by RAD ALT when DA is reached.
Is it your contention that one could (i know you wouldn't) ignore the bar alt and judge DA using only Rad Ht indications? i.e.. the rad ht and bar alt indications would display DA and DH at the same point in space?
According to me this is a no no! Rad Ht should never figure in DEFINING DA/DH during a conventional Class 1 ILS. Or for that matter figure in the definition of MDA/MDH.
Surely people must realise that the terrain is not uniformly flat enough on the approaches to many airfields where the DA/MDA is outside the airfield perimeter (LEEDS, BRISTOL, SAO PAULO, etc.)
G.