Not quite sure what your question is.
Although I am in Kiwiland, I have just looked at the approach plate in the ASA database. Over here it would be called an NDB/DME RWY 16 as the DME is required (no overhead NDB to start a timed approach).
Looking at the chart, it would seem that BOL is needed to be able to navigate to the commencement of the approach and ROC is needed to conduct the approach.
If you have 2 ADF's I imagine it would be personal choice on what you select for each. If I were flying that approach I would have one on BOL and the other on ROC main reason is that I wouldn't want to be pissing around after having crossed BOL changing freqs and identing, particularly single pilot ops, when at a critical stage of flight (configuring for descent, approach and landing). Each would have been tuned and idented before commencement of the approach (prior to BOL) so all I had to do after crossing BOL was change which dial I looked at.
NDB's are slowly being phased out over here. Where the airfield has a VOR, NDB - the NDB is being removed with the introduction of a GPS type approach (GNSS/RNAV etc etc). Enroute NDB's will slowly go as well as the system becomes more and more RNAV routes. It won't be long before the youth of tomorrow go "a non directional what or....coastal refraction - never heard of it or....what are all these round dials with needles or......gee, you mean back in the old days you could break the glass on a pressure instrument if the static tube blocked..wow.
I digress!
Last edited by conflict alert; 4th May 2010 at 18:51.