The procedure states " Proceed according to the current flight plan route to the designated navigation aid or fix serving the destination aerodrome hold over this aid or fix until commencement of descent"
1. If one is cruising at FL340 does it mean that altitude is maintained and descent commences over the designated nav aid or fix? OR does it mean descent is commenced at the normal point in the Flight Plan and holding is maintained at a point appropriate for the runway in use.
That is the IFR procedure. ICAO standard is to maintain last assigned level (or minimum safe altitude if higher) for 7 minutes (20 minutes in a non-radar area) and then as per flight plan. So you will descend as planned. Refer to ICAO Annex 2.
2. There are some airports where there are no designated navaid or fix. What is the procedure then?
If you filed IFR then there will either be a fix for an IFR procedure or the weather will be so good you can land in VMC as per the VFR radio failure procedure, ie you just maintain VMC and land at the airport (not forgetting to watch for light signals if there is a tower).