Originally Posted by
vilas
Flying the approach conventionally without the FMS, at DME fixes you sometimes land up high or low and then correct the descent for the next DME. In this procedure the DME fixes are hard safety altitudes you cannot go below. So you will have treat them as minimums and that cannot be progressively done all the way to the lowest minimum of 2.8DME. so if the fixes are not coded in the FMS then the highest minimum will apply whether you use the FMS or fly with manual vertical guidance.
My CAA’s standards doc. for the IR Skills Test states: ‘Not below’ minima (from FAF altitude down to MDA/H) vertical tolerance -0’, so this is well established and part of normal operations. If you think you might go below a hard altitude approaching a fix, you reduce the rate-of-descent so you don’t.
The procedure under discussion is not available without DME, so the fixes will always be there to check. If you don’t have an FMS but do have a VOR receiver with DME, you should be able to use the lowest minima for your aircraft category? An FMS 3D approach has different tolerances.