NDB approach - Do you ADD an allowance for "sink" ?
Given an ILS DA has an allowance "built-in" for a shallow dip below the published DA during a GA, I am surprised to learn that a UK company has added 50' to the MDA for NDB approaches, so there is less chance their aircraft dip below the MDA during a GA from "limits".
Forgive me chaps if my knowledge base is out of date (being three years retired now) but my understanding was that you must NEVER dip below the published MDA published for an NDB approach; and despite a definitive figure published in the appropriate manual, there was nothing about adding this 50' business to any MDA so published.
You were left to your own skills to NEVER go below the MDA for an NDB.
Is there any other company out there adding this "sink allowance" of 50 feet to the NDB minima ?
Best wishes,
TG