If Redflyer is a Flybe pilot he/she should not be writing this kind of garbage about IFR GA. This kind of prejudice doesn't do anybody any good, although it isn't uncommon within the "gold plated pilot" community and probably explains a lot of regulatory difficulties elsewhere to which nobody will own up publicly.
A TBM850 has better kit than a Dash 8, in all probability.
Of course multi crew ops are safer than single crew ops but what he/she wrote is just garbage, in the context of an appropriately equipped aircraft. The C152 someone might do their IMCR in is something else, but this was a TBM.
If you T,I,M the navaid before starting the procedure whilst flying the FMS track then any discrepency should be obvious prior to descending below MSA.
Yes, of course. I was kind of making the point that there are plenty of coastal NDB approaches on which you get a 20-30 degree error, which starts at not much at say 10D, reaches the 20-30 degrees at say 3D, and then disappears at say 1-2D but by then
if you blindly tracked the ADF (as you are supposed to on your IR initial) you are so far off track by the time you get visual at the MDA that you will have some fun getting in. I have spoken to loads of airline pilots about this in person and generally their SOP is to check the ADF at the FAF only and then track the FMS inbound, and the NDB has to be idented, apparently functioning (not that you can actually tell), and not notamed as INOP. One Dash 8 pilot, non UK, I spoke to a few months ago does exactly this, for VOR and NDB approaches, but they don't even need to check the navaid indication at the FAF; it merely needs to be idented and not notamed INOP.